Air source heat pump (ASHP) design and installation practices have a major impact on system efficiency and performance and can affect customer comfort and satisfaction. This module provides and overview of the design and installation considerations as well as homeowner education to help ensure efficient air-source heat pumps and comfortable customers in cold climates.
By the end of this module attendees will be able to:
• Understand heat pump water heating technology and its applications
• Determine the most appropriate system size and configuration
• Recognize the signs of a quality installation
• Properly commission new installations
Speaker: Adam Romano, Principal Building Systems Consultant of Steven Winter Associates, Inc.
the broadcast is now starting all attendees are in listen only mode hello good afternoon everyone my name is Anna zyc and I am with ICF we are the vendor working on behalf of the sponsors of energized Connecticut to bring these passive house trainings to all of you so thanks for joining us today we will be recording this training and we will make this available afterwards to you all these trainings are at no cost to the sponsors of energized Connecticut and are a part of a partnership with Connecticut passive house a quick reminder that as part of this training and Workforce Development initiative we are offering a 50% cost reimbursement for individuals pursuing either fi or fee professional accreditation so this includes the cost of the training and the exam and once you become certified we’ll work with you to process the 50% cost reimbursement so if you have any questions about that please don’t hesitate to contact us and with that I will pass it over to Keegan who’s also with ICF to talk about the passive house building incentives thanks Santa and hi everyone uh thanks for joining us today uh in addition to this no cost educational training series and the professional accreditation reimbursements uh the sponsors of energized Connecticut also offer incentives for Builders and developers who choose to pursue passive house certification in uh multif family residential projects of five units or more next slide Adam uh the passive house incentive design for energized Connecticut is shown here on the slide it includes preconstruction incentives for things like feasibility studies and energy modeling and post construction incentives for full passive house certification through either fius or Phi our goal is for everyone involved in multif family construction uh residential construction in the state of Connecticut to be aware and understand these incentives so if you’re interested in learning more please do visit the website or contact us at the information here on the slide uh and for to questions during today’s session uh use the chat function uh throughout and Anna and I will relay them to Adam as we go and with that I will turn it over to today’s uh presenter uh Adam great thank you very much Keegan um so today uh we are going to be talking about heat pump design and installation best practices um my name is Adam Romano I am a principal building systems consultant with uh Steven winter Associates my contact information is up here on the screen um if any questions happen to come up um after the presentation you want to reach out or you have a project you’re working on and need a little assistance please always feel free to reach out to me um a little bit about Steven Winer Associates um we uh are a consulting firm that provides um energy conservation and Management Services sustainability Consulting Green Building certification accessibility Consulting we do a lot of research and development and a lot of Workforce Development as well uh our information is up here on the screen s winter.com is our website so with that there’s been a lot of talk and a lot of you I think have you know been in this movement and a lot of talk about electrification uh in the last few years and there’s been a few drivers that really uh have pushed the need to find electric based solutions to the Forefront um and you know mainly that is you know looking at ways to reduce carbon emissions um locally in in our building stock um there’s other benefits as well besides you know the carbon emissions reductions I mean obviously we have improved local air quality from uh not burning fossil fuels locally um in our homes um that translates into improved indoor air quality um there’s a reduced risk of carbon monoxide exposure because again we’re not burning those fossil fuels um there’s Comfort benefits uh as well uh to moving toward electric based systems especially when we look at some of the systems that can provide you know more of a zoned approach to design uh and then in certain parts of the world there is cost savings as well depending on the cost for fuel and how that balances out um so there’s been a lot of you know sort of uh movement and momentum towards uh you know electric based Solutions and you see you know it’s uh these electric based systems applicable to a lot of different construction types um obviously new single family homes is one that is is a great uh spot for electric based systems um because we have much much more control over the loads um we’re doing a good job of air sealing insulation a lot of the detailing on our enclosures um that helps make the loads a lot lower and makes the systems a lot more applicable um so you see that we can do a real good job uh designing and installing these systems to really optimize performance um in new single family homes um they’re also you know you know applicable to existing uh homes as well um we see a lot of retrofits taking place uh all across the country um and here you know a lot of it is driven by paybacks and return on investment when we’re looking at uh you know switching from uh delivered fuels to uh electric based heat pumps um and uh we also see a lot of beneficial cooling uh being added as well in in projects that don’t have a dedicated uh Central cooling system so there’s a lot of momentum in the existing single family Market as well um and in the multif Family Market Market obviously you know uh you know heat pumps can work well in different building typologies and uh you know multif family is one of those as well um so we see a lot of heat pumps being installed in high performance uh projects uh and they perform very very well when we have you know equipment that is selected correctly um that’s where we see a lot of good performance and that’s kind of what we’re going to be talking about today is really making sure that these systems are designed um selected and installed correctly in order for us to ensure that performance um sometimes you know we see performance gaps uh or issues that come up post installation and a lot of it stems back to those um those variables So today we’re going to talk through a few different things uh during this uh webinar we’re going to understand how these heat pumps work and and their applications we’re going to determine the most appropriate system configuration for different types we’re going to recognize the signs of a quality installation and we’re going to talk about some of the the commissioning uh of new installations as they start get U get started up so with that let’s jump into uh system design uh here we’re going to be talking about sizing and selection so when it comes to you know uh sizing selecting these types of systems I mean the first thing we need to understand is the requirements um is we need to make sure that uh we are going to correctly size uh these heat pumps and select them correctly because that really ties into the efficiency and the performance um you know if we if the capacity is too low uh the system is going to go into defrost more during the heating cycle um it’s going to not be able to meet the load uh which is going to cause uh you know um inefficiencies and performance problems if the capacity is too high we may have excessive cycling and poor performance at you know warmer temperatures uh that you know can pose an issue as well so we really need to gather all the information that is needed um to really understand what’s going to be the most appropriate system type for our particular project and a lot of that goes back to the goal you know things that we’re trying to accomplish with installing any type of uh HVAC system we’re really trying to maintain comfort we want to make sure that the system is going to work economically we’re going to have you know a a proper cost in terms of the operational cost and we want to make sure that you know we’re uh paying attention to how the system is installed so that we don’t have any sort of environmental impacts from things like Refrigeration leaks and and and that alike so we really want to make sure that we’re you know always going back to those goals and making sure that we’re trying to achieve them as we start to go through this entire process and a lot of you know sort of the the selection uh is also going to depend on the layout of the particular home or the particular project that we’re working on um is you know the space more of an open floor plan um if the space is open like that um then we that may lend itself to more of a a duckus option um if the space is much more compartmentalized uh we may work towards more of a ducted solution right we we want to be able to make sure that you know we’re selecting the this equipment uh and that and it’s going to work well in uh with the configuration of our particular space um so that’s one of the the main drivers is kind of how you know the space is laid out uh can kind of dictate the options that we would go for when we’re looking at selecting uh terminal units on the in in the interior and then also I guess said proper sizing is going to be important as well it’s sort of U it’s like a sort of a gold delock issue right the the idea is we want to make sure that we’re not installing something that’s too small or too big you know it needs to be just right uh and if the system is too small you know we’re not going to be able to perform we’re not going to be able to heat the home adequately heat the space adequately or cool the space adequately uh during those parts of the season um so we’re going to have poor you know comfort as the result um if we are looking at this as a retrofit scenario and we’re keeping some existing systems in place we May rely more on backup or auxiliary uh heating or auxiliary systems to be able to uh meet that load or meet the balance of that um we may also have issues with uh catching up after setbacks you know if we are utilizing you know let’s say programmable thermostats we you know performing a setback during unoccupied times it may take a lot longer for that system to recover uh when the space becomes occupied so all those things you know really um you know are a result of a system becoming or being sized too small now too big is is is an issue as well here we’re going to have poor Comfort because we’re going to be overheating spaces um or over cooling spaces or not dehumidifying the space uh we’re going to have poor Energy Efficiency as a result because the system is going to cycle because it’s not going to be able it’s going to be too big for the application uh we can have poor durability right uh if as we’re cycling the system more and more and more uh we also have issues with you know stressing out components more and more um so we may not you know see the expected sort of useful life out of this equipment over the time because it may be cycling more frequently than it was initially intended and it’ll be more expensive the operational cost will be higher because our capacity is too big uh the first cost will be higher because the equipment was installed that was it was too large um so all of these things you know sort of come into play when we have a system that’s too large so we really want something that’s that’s just right and that’s going to provide us with you know our goals the Comfort efficiency and durability now during this training you know we’re not going to get into all of the the sizing aspects but we will point you in the right direction in terms of resources that are out there so you know we’re not going to go through you know manual J manual D manual T manual s and and how to you know design and and perform a heat loss calculation and uh and design duck work and things like that those manuals are readily available there’s there’s training on that um there also are guides that we are going to point you to in terms of sizing and selecting air source heat pumps in cold climates um so NE the north Northeast Energy Efficiency partnership uh there’s two links here uh to a guide for sizing and selecting and a guide for installing these uh heat pumps in cold climates um and those are great resources that will complement uh this training and will you know sort of uh help you you know navigate uh some of the um know your projects as you start to go go along now once we have the system sized right so the idea first is to make sure that we have a system again it’s not too small it’s it’s not too big it’s just the right size now we need to sort of select the system type you know how what kind of heat pump are we going to install so we have a couple of options you know when it comes to system configuration so one of the things that you can you know opt for and we see this a lot uh in in projects is you know going for smaller units and having smaller Mini Splits you know uh you know taking care of parts of the load throughout uh you know a building um so we can have these smaller sort of decentralized air source heat pumps systems and these are typically you know uh you know ton and a half you know two ton 3 ton systems um that can go ahead and uh you know carve out you know and and take care of a piece of the load uh these systems again have one indoor unit one outdoor unit so they’re this onetoone configuration uh the indoor units can be a lot of different types um you can have a low wall or a floor mounted unit as you see here you can have your traditional you know high wall ductless unit you can have uh ceiling cassettes you can have ducted units uh that are compact ducted um so you have a lot of options in terms of the terminal unit that’s going to fit your space best and again going back to is the space more compartmentalized or is the space you know more of an open concept we can you know determine whether we’re going to go with a ducted or a ductless approach in that case um and uh if we want to combine you know some more spaces together you know for one uh larger system so if we have areas that are uh going to you know sort of have the same kind of you know Cooling and heaing load and we want to go ahead and combine them into one larger system we may move up to sort of a multi-split uh where here now we have multiple indoor units uh that are now tied to one outdoor unit uh and then here you know we have refrigerant piping that’s going to go to these indoor units and again we have the same sort of flexibility when it comes to the the terminal units whether they’re going to be you know floor mounted or high wall or you compact ducted uh we have some flexibility there within the manufacturer’s um uh requirement or you know capabilities and then here again it’s one outdoor unit multiple indoor units a little bit larger in size here you’re going up to your 4ton your fton uh systems so again you have a little bit of a larger system now one of the things we will you know sort of caution with this approach uh and this is you know very uh you know sort of relevant for Passive house projects where we have uh very low internal loads is that sometimes we see performance issues with uh these multisplit systems and the performance issues come in be play because of those lower loads now these units can modulate down right that is one thing that makes these units uh very very attractive is that they have the ability to ramp up ramp down they can modulate their capacity but there is going to be you know sort of a minimum uh capacity that they they can’t really go down below right especially when you have a lot of connected uh terminal units in in uh in the building so there’s going to be a minimum Capac capacity that you know that’s as far down as we can go when we come to to ramping down now if that minimum capacity is is greater than your load uh then you may have issues with cycling and that ends up causing the units to be less efficient over time and because essentially those terminal units are oversized for that particular space right so if we let’s say an example of a three-bedroom you know home if we put one duckass unit in each one of those bedrooms and connect it to a a multi-split unit outside you know chances are in certain periods of time that that you know those units are not going to be able to modulate down to meet that load especially in an efficient building uh and that is you know one thing that you know we do see a lot and manufacturers now are starting to recognize that and see that um as you know projects are being uh you know commissioned and and getting into operation that you will have some issues if those units are larger than your load right and you can have things like overheating obviously because now you know we have to shed the BTUs we have to get them out into the space uh overheating can be an issue during the cooling months uh humidity can be an issue right because we’re rapidly we’re doing a lot of sensible cooling at that point we’re bringing the temperature down but we’re not doing any Laten cooling we’re not get doing any dehumidification because the units are larger than uh the load in the space um and we can also have higher than expected energy use right because now again the unit is bigger than what we need um so all these things go into that so when you have these you know high performance buildings with these very low internal loads what we like to do we like to see you combine more of those spaces and and then go upt for more of a ducted solution at that point instead of going with ductless because now we can combine those spaces we can have one internal unit uh and that the load can be higher than its minimum its minimum turn down so that’s something that you know we like to see or you split it up and you say okay well you know we’re going to now put three One to One units that are going to serve that space uh instead of one big unit unit that’s going to serve multiple spaces so there’s ways around that but that’s one thing that I would caution and just make sure of is that you’re look at all the performance data to ensure that the system is going to be able to modulate down to your expected loads uh and then the other option besides uh sort of the the multi-split and the mini split uh we have a traditional sort of central split systems uh where you know we may want to uh go and fabricate a duck work system all right and have a traditional sort of air handler connected to an outdoor unit uh and then that’s going to serve the space through you know traditional duck work uh duck work system uh here you know this is you know very reminiscent to the more conventional uh AC systems they’re typically come in the two to five ton range uh again they’re going to be fully ducted uh and here you know sort of uh the approach is to really make sure that the duct work construction is done very very well um one of the things that we find with uh heat pump systems is that that the discharge temperature is not as hot as you would find with a traditional fossil fuel based system um so if we Are Burning uh oil or burning propane or natural gas discharge temperatures can be you know above 130 140 degrees whereas you know with a heat pump are typically around 110 120 degrees so all the heat that we are generating even though it is enough to be able to heat the space we need to make sure we’re not losing any of that heat along the way so we want to make sure that the duct work is insulated it’s air sealed um so that all that air can get to the spaces it needs to get to in order to properly condition them um we also want to pay attention to the size of the duck work because we want to make sure that we maintain proper velocity as the air gets distributed down the line so all the good sort of duck work practices listed out in manual d uh we want to make sure that we’re following when we have these uh ducted systems and that’s you know any any ducted system whether it’s compact or if it’s you know sort of centrally ducted like this now when it comes to you know selecting once we figure out sort of the type that we’re going to use right so whether it’s a central system or a split system um what are we going to you know sort of Select now it comes into okay well what type of manufacturer and you know what type of unit we’re going to put into uh this project and here I’m going to go back to that uh neap.org uh and look at their database now one of the things that you see when you look at conventional heat pumps is that the way that the capacity is reported uh traditionally you know leaves you know sort of um some questions right so when you look at traditional heat pump performance uh they’re typically rated at 47 degrees Fahrenheit and 17 degrees Fahrenheit and you know that’s fine if you know one of those happens to be your design temperature but if your design temperature is you know below you know 17 degrees uh then you know sort of what do you do you know because you need to make sure that your system is going to be able to heat the building at at the coldest expected temperature and you the relationship between that 47 and 17 you know may not be linear right you may not be able to extrapolate that out and say okay you know at you know 15 degrees 12 degrees 10 degrees we’re going to see this because the drop off may be more severe it may not be a linear relationship between capacity and temperature so we really need to get into more of the engineering data to see okay well how do these systems operate down at my expected you know outdoor design temperature uh and that’s what you know one thing that uh you know this database has done is really allow you to compare systems uh and really get that data and much much more easily instead of running through engineering manuals to try to find uh that data so here you can see one example unit this is a 18,000 BTU uh uh split system that is uh non-ducted um and we can see we on the right hand side we have all these detail performance specs right we have the cooling capacity uh up at to 95 degrees U we have heating capacity all the way down to 5 degrees um and what they’re showing here is the minimum capacity as well as the maximum capacity and then also the efficiency so the coefficient of performance how efficient can we move this heat um at those particular uh temperatures so this makes it a lot easier to ensure that you know our systems are going to be able to move the right amount of heat or the amount of heat that’s needed for our lower ambient temperatures or you know down to five degrees in this case so that was our outdoor design you know this unit can provide 15,400 BT at you know at 5 degrees uh and that we want to make sure that’s adequate for our space so this is great to sort of reference and every manufacturer is going to be a little bit different right so some some units are going to be kind of engineered uh differently um and that’s something that you also have to pay attention to you can’t just say that oh one you know 18,000 BTU unit is going to be the same as another unit because they may be slightly different in terms of how they’re designed and how they’re engineered so we have a little example here in terms of comparing uh two units that are on the list that meet the specification uh these are both one ton ductless heat pumps we have heat pump A and B and we’re going to look at sort of the capacity and the efficiency at different outdoor temperatures so we can see here that heat pump a in this case at 47 degrees uh outside temperature can produce 18,000 BTUs an hour can move 18,000 BTUs per hour uh which is you know greater than its nominal capacity of 12,000 BTUs because it’s a one ton ductless heat pump uh heat pump B can do uh can move even more heat it can move 21,000 b2s per hour but you can see the efficiencies are a little bit different so for heat pump a the coefficient of performance is 4.15 so it’s producing a little bit less heat but it’s doing it in a much more efficient way whereas you know heat pump B is down to 2.68 so it’s providing more capacity but it’s doing it in a little bit of a less efficient way and that’s going to be important because again these two are not going to be equal as we get into uh different outdoor temperatures here we’re down to 5° and we can see now the difference starts to get even greater right heat pump a now can only produce about 8,000 BTUs whereas heat pump B can produce about 13,000 BTUs and the efficiencies you can see 2.81 for a and 2.21 for B so you can see that you know heat pump a is being designed more for you know efficient operation at higher ambient whereas heat pump B is being designed for more capacity at lower ambient temperatures and it even becomes more clear as we get to even colder and colder outdoor temperatures here we’re down to-3 heat pump a doesn’t even show any data for that particular outdoor temperature whereas heat pump B can still produce about 9,000 or almost 10,000 BTUs uh with a cop of 1.81 so again from the from the outside just looking at these units without peering into all the detailed sort of engineering specs uh you would think okay the performance should be pretty you know pretty much the same whereas you know but if you really peel the onion back a little bit you can see that um you know systems are definitely different uh and that’s something that you know this you know sort of specification and this database really helps to illuminate is you know what system is going to provide me the most output or the output that I need uh with you know the greatest efficiency um and you know that’s kind of you know the example here is you really need to compare different types of systems for your application because they’re not all going to be the same so once that is all done once we say okay we’ve sized the system it’s the right size we selected the right configuration uh we made sure that it’s going to provide you know uh capacity in an efficient way now we need to get to the the part of installing it right because that’s the the second you know biggest issue when it comes to uh heat pump performance is you know proper installation really does matter uh in terms of how these systems uh get installed and and their long-term performance and and capabilities so let’s shift a little bit and talk about some of these installation considerations um now we’re going to break that up and we’re going to talk a little bit about indoor units and then outdoor units so on the indoor unit uh you know placement is going to be important right just because we selected the system correctly and we sized it correctly you know we still need to make sure that it’s uh it’s in installed and it’s placed in the interior in in an efficient way so we want to make sure that you know it can broadcast air into the space so we can adequately sort of heat or cool that space we also want to make sure we have enough clearances for uh for service um you know you know having a unit that’s 15 feet up in the air is going to be very very hard for the end user to change those filters and those filters may not get changed frequently enough they that may cause performance issues so all of this has to be taken into account when we’re designing on deciding on where we’re going to place this this indoor unit uh we also need to make sure that we have proper clearances from the ceiling so that we have adequate air flow into the return side of the the unit um and we also want to make sure that uh again the unit is available for service if you need to open up the side panel we want to have clearances to the left and to the right to be able to service that unit if it needs a motor replacement or if it needs you know more invasive you know service now high wall units like this uh we have there are some issues with placing them very high in heating dominated climates um and one of the things that we you see and if you look at some of the the data from manufacturers is that as you start to place these units higher and higher on the wall or higher and higher in the space uh they tend to work a little bit less efficient during the heating months and that has to do with you know sort of the properties of air as you heat air up it’s going to become lighter it’s going to rise to the top of the space so we’re going to have tend to have higher uh air temperatures at the ceiling level compared to the the floor level and as you you have these elevated temperatures up at the ceiling that t that you know is you know correlates right where the return uh air duct is for that particular unit so we’re it’s pulling on a ductless unit you’re pulling air in from the top and you’re discharging it through the front now if you’re pulling this really hot air you know relatively hot air uh from the ceiling into the return uh it’s going to be much harder for that unit to uh sort of impart the BTUs to be able to transfer the BTUs from the coil to the Airstream because as the delta T gets smaller it becomes harder and harder for that system to move the BTUs to that air uh and that’s what you see here on this uh on this diagram here on this chart you can see as the return air temperature goes from 65 to 75 you see that your capacity drops because again we’re not moving the BTUs effectively and our efficiency drops because now we’re returning more BTUs to the outdoors so when when you’re looking at placement of This indoor unit and you’re in a in a heating dominated climate uh and you’re going to spend a lot of time in in heating mode it may be better to move towards a floor mounted unit um it may be better to move towards a compact ducted unit where we can return we can you sort of control where the return air comes from that kind of you know alleviate these issues because we have seen performance uh problems or performance degradation when you have these units up really high uh and they’re pulling in a lot of that hot return air uh what it also comes to indoor units like this when they’re uh ductless um I like to see a overflow or a wet switch installed as well uh because these are in the Interior Space um and you know they’re there if we have any condensate uh blockage in the condensate lines or if we have a blockage in the in the condensate tray um you know we don’t want uh you know condensate to uh spill out uh and damage interior uh finishes so having a wet switch there an overflow switch there is cheap cheap insurance to prevent that from happening because it’ll de-energize the unit during the cooling uh season uh prevent that uh pan from overflowing uh and you know and save a lot of the Interior finishes um so that’s something that I always like to see on endure units in duckass uh in the duckus unit uh is to make sure that we have this form of a disconnect if we had a blockage um especially if you know maintenance is not being done correctly if uh filters are clogged uh you tend to have uh more debris getting into those condensate pants uh now uh outdoor units are also important in terms of the placement um so you know you want to make sure again we have adequate air flow uh going through these units um if you look at these units in particular a lot of the coil surface area is behind the unit so we need adequate you know sort of uh offset from the structure so we want to make sure that we’re maintaining you know manufacturers clearances you know 12 in 8 in whatever it may be from those Manu ufacturers you want to make sure that we have adequate clearance from the behind and from the side um this way we can have good air flow going through those those coils um we also want to make sure that they can be serviced right so we want to make sure they’re in a spot where uh it’s easy to be able to service those units clean off the coils you know check all the Electric electrical connections that’s going to be an important aspect as well uh these brackets that you see here are very common uh a lot of folks like to get them up off of the the ground um and you know so one thing we need to make sure of when those brackets are installed uh is that they are anchored very well into structure a lot of these units especially when you get into the multi spits uh that are higher capacity um you see a lot of uh these units weighing 300 pounds 400 lbs um so we need a bracket that can support that kind of weight uh we need to make sure that it is you know secured you know into that structure so that we can uh have a a good sound uh installation there uh these units uh also we would like to see some sort of vibration isolation from uh the unit to the bracket itself even though the units are very quiet and they ramp up you know with these variable speed compressors we’re not you know heart starting them they’re going on very gradually they ramp up you know very slowly um but the issue still happens when you have you know very cold temperatures uh and those compressors are moving at very high RPMs uh there’re may be some uh you know vibration that gets transferred into the uh into the structure uh so we do want to see vibration isolation on those legs um and then also proper uh Fasteners to be able to secure that unit to the bracket you know that’s going to be very very important as well uh if you choose to install these units on a pet um that’s the other option instead of using a wall bracket uh here you want to make sure that the pl pad is level uh you know we see this a lot especially level over time right you know it tends uh these you know when these in uh systems are installed on these fiberglass pads or concrete pads sometimes they tend to settle uh and then you go back 2 three years later and you see that the unit is not level anymore and that can have an impact on lubrication at the compressor so here you want to sort of dig down and make sure that you can pack the soil um or use some sort of you know stone dust or um or drainage Stone to be able to make sure that we have a good level surface that’s going to stay level uh for long periods of of time um and then here you may have to install feet to get these units up off the ground um because we do need to pay attention and we’ll talk about this later uh to snow clearances right so we have an anticipated snowfall amount we need to get the units up off the ground so they that they can drain properly during defrost um and they’re not impacted by you know the snow uh surrounding them sometimes you see outdoor units stacked um so in certain situations uh outdoor real estate becomes very hard to find uh and you may uh you know want to sort of Stack these units where you have one unit installed above another um the one issue that we see with this and this happens uh frequently is that uh during the heating months uh these units may go into defrost at different times and if the unit above goes into defrost while the unit below is still in heating mode any of the runoff that is produced during the defrost cycle is going to drip down onto that unit below and if that unit below is in heating mode uh those coils are going to be very cold uh and that runoff may start to refreeze on that bottom unit so here if we are going to stack units uh we like to see that there’s some sort of um you know uh piping or some sort of way to divert that runoff so that it doesn’t go onto the bottom unit uh because as it goes into the bottom unit it’s going to go into defrost cycle more often it’s going to reduce its capacity because it’s going to be harder to move air through you know a frozen coil uh and that’s going to cause performance issues with that bottom unit so we need some way to kind of divert Burt that away um so that it is not impacting that bottom unit now runoff from defrost is not the only thing that we’re worried about when it comes to uh these units in uh heating operation sometimes you may have uh you know parts of the roof line that do not have gutters and leaders uh and you know water during you know rain events May go down and fall on top of these outdoor units uh as they are in heating mode uh and that may cause them to uh to to freeze up so we also want to pay attention to that you know where are these units being placed with respect to different roof lines uh and uh if it it has to go in this one location uh we have some sort of fabricated option like you can see on the right here that is going to kind of catch that uh water and divert it away from the unit so it’s not going to impact its performance because the same thing is going to happen here we’re going to have that water run off it’s going to freeze on the outdoor unit and it’s going to impact air flow uh and it’s going to impact uh system performance so that’s something that we want to pay attention to as well when we’re citing that outdoor unit as I mentioned before uh snow is a design consideration right in you know in our area we are going to get snow snow typical snow depths are going to you know vary depending on where you are uh but that’s something that we have to pay attention to is making sure that the unit is up high enough that it is not going to be impacted uh by a snowfall event um the unit is not going to be installed let’s say in an inside corner of a home where you can have snow drifts uh several feet high that can uh impact the performance of the unit um and also just education for the for the end users you know you may have to go out there and clean the units off uh make a path uh you know remove some of the snow that’s surrounding those units uh during the uh during the winter because you know again you want to make sure you’re maintaining those proper clearances um ESP especially if this is your you your sole source of heat we need to make sure we’re getting good air flow through the unit even if it is snowing outside once you select the location for the indoor and the outdoor unit uh the next process is now routing the refrigerant line set so we need to be able to get uh the connection made from the indoor unit to the outdoor unit um so here when it comes to best practices for line set installation uh we would like to see uh the use of a tubing Bender uh being employed um because again this is ACR tubing uh we can go ahead and bend this tubing as opposed to using joints and we’re really trying to here limit the amount of joints that we have to field fabricate uh and uh limit the potential for refrigerant leaks um so because this tubing can be bent fairly easily you can use a variety of tubing benders to go ahead and manipulate that piping um so that you can Route Around objects and and get from point8 to to point B um so that is something that you know we like to see used a lot uh when we when it comes to our line set routing and and installation now there’s going to be times where it’s it’s inevitable and you have to go ahead and fabricate a joint in the field um so here you know when we are making you know joints in the field uh we do want to make sure that uh we are following proper brazing technique so that those joints are brazed um so we’re using acetylene and we’re using a brazing rod um and we want to make sure that uh the filler material completely fills uh The Joint itself we want to make sure that we’re properly heating both ends of that copper pipe so that we have good flow of the filler material inside of that 90 for in this case um and we also want to make sure that we are uh purging nitrogen through the Lin set as we are brazing the the pipes together um and you know that what happens here if we don’t Purge nitrogen and remove the oxygen inside of this pipe as you heat that pipe you know with that acetylene torch um you are going to uh have an interaction between the copper and oxygen and copper oxide is going to form and that’s what you can see on the bottom here is that all this black copper oxide has formed inside of the pipe now that becomes an issue is as that flakes off as the refrigerant is allowed to go into the Lin set um it’s going to go ahead and interact with that copper oxide flakes of that copper oxide going to break off um and they can pose an issue to devices that are Downstream such as your electronic expansion valves that are very very small openings they’re metering the refrigerant into the you know into the coil um and if one of those little flakes of copper o oxide gets caught in there um that can cause you know an issue with uh with operation so we want to make sure that as you know the brazing is happening that uh nitrogen is being purged through uh and they make Regulators like you can see on the bottom bottom left here that have braze settings um so they’ll just Purge a little bit of nitrogen through displace that oxygen while the brazing process takes place and you can see the the joint on the top uh had uh n nitrogen going through uh and that is now nice and clean on the inside um so this is going to be very important for when you have to make joints between uh the indoor and the outdoor units now the other method of joining piping together and you see this at the terminal units at the outdoor and at the indoor unit is the process of making a flare so this is more of a mechanical connection uh between the copper piping and the uh the brass uh um coupling uh so here you want to make sure that you’re using a good flaring tool uh the flare is a uniform so you’re kind of spaying out the copper uh usually it’s about a 45 degree angle uh you want to make sure that it’s uniform all the way around it’s the proper depth um it’s not you know misshapen uh and then when the uh flare nut is uh you know attached to the to the unit uh you want to make sure that uh you’re not using too much force um so most manufacturers will recommend using a torque wrench uh and making sure that uh it’s snug uh but it’s not too tight uh when you tighten up that flare nut too much it puts a lot of stress on the backs side of that flare and because again this is ACR tubing it’s pliable uh you can start to see that flare you know U um get flattened and in extreme cases the copper can crack uh and that’ll cause the refrigerant leak so we want to make sure that you know the flares are made correctly and uh we’re not overtightening uh that flare nut when we uh you know land that uh line set to the indoor unit or to the outdoor unit uh and now once we made our connection so our connections now made between the indoor unit and the outdoor unit uh now we need to make sure that we don’t have any leaks so the next process is to to pressure test uh these units uh pressure test our line set you know this way we have you know uh confirmation that we do not have a refrigerant leak uh so here you’re going to pressurize it with h dry nitrogen typically over 500 PSI recommended by most manufacturers uh some manufacturers would like to see a standing test for 24 hours and then you would go back and re-evaluate to see what kind of pressure you have um after that period uh some are shorter um so you want to go in and just follow the manufacturer’s recommendations to ensure that we have you know proper joints that are made um and that we don’t have any leaks uh between those two uh units uh because again the big thing with this is that you know we don’t want the refrigerant to leak out um it’s you know a performance issue and it’s a um you know a big performance issue a comfort issue but it’s also a big environmental issue right we don’t want that uh you know um that refrigerant leaking out into the atmosphere because of the effects it had has uh when it’s uh when it’s leaked out its global warming potential is very very high uh typically with 410A and other refrigerants so this is going to be a very important part of the installation process is really making sure uh that we don’t have any leaks um uh on the joints that we’ve created in the field once the uh everything is made up and we feel confident that uh we are leak free now uh we have to sort of reinstall some of the Lin set installation because again as we’re brazing or if we’re making a flare typically we remove a section of the insulation uh and now we need to sort of reinstall that so we want to make sure that our installation on the line sets is continuous um it is you know goes from end to end we don’t have any gaps uh it’s properly secured um we like to see uh the use of a line set insulation that has a integrated UV barrier uh because as the line set exits the home or exits the structure and uh connects to the outdoor unit uh if it’s exposed to ultraviolet uh light from the sun uh you usually see degradation of that insulation and there’s plenty examples if you go back you know two three years after an install uh you see that the insulation is is falling apart and it’s coming off of the uh of the piping and that’s due to the UV exposure so we want to see one that has you know an integrated UV barrier or we want to see a UV wrap um installed around the uh the line set to make sure that we’re protecting it from uh from that degradation uh then we also need to detail uh the uh exit point so as the line set is uh going out of the structure um we want to make sure that it is properly sealed now folks in the passive house Community you’re going to use a lot more robust connections there um to make sure that we have a good air seal we’re maintaining air barrier continuity uh but you want to make sure that that that does take place that we have a good detail for those pipes uh especially if we have multiple units we’re going to have a lot of uh you know penetrations through our air barrier so we want to make sure that we’re properly detailing all of those pipes as they exit and they go towards the outdoor unit uh you can also dress up the line sets on the outside uh there’s a variety of products that can be installed you know line High you know things like that where you can cover the line set so they kind of blend in uh with the exterior of the building uh once that is all set up then we can evacuate uh so the line sets before we can introduce refrigerant into uh our system we need to remove all of the air and any of the non-condensables uh that are present inside of the copper piping that we’ve just installed uh so we’re going to use a vacuum pump here to remove uh all of that um we want to get down to at least 500 microns if not better um if you’re finding it hard to get down to 500 microns uh there may be a couple of things you may have uh you know moisture in the system uh you know especially if the station happened over a period of multiple days uh and maybe it did rain and the Lin set wasn’t capped off uh during that period you may have good excess moisture inside of the the line set and that may take uh you know a triple evacuation process or multiple vacuums to really pull all of that moisture out um it may be due to a vacuum pump oil being old um so you do need to maintain the oil in your vacuum pumps um if the oil does get old uh then it becomes very hard for that vacuum pump to get down to those uh those levels um or you may have a leak right so that then you may have to go and reinvestigate your your joints and make sure that we don’t have a leak um because if we can’t get down to the 500 microns it may be that air is coming in at some point uh through a very small leak on one of the joints or one of the flares once we achieve that uh that that point then we want to go ahead and charge if we need to charge um so you know depending on how long the line said is between the indoor unit and the outdoor unit uh we may have to add uh additional refrigerant uh to make sure that a refrigerant charge is adequate uh so that’s something that we’re going to do with a digital scale we’re going to ensure that we are following the manufacturer’s guidelines into how many ounces need to be installed uh you know per you know excess footage uh and then make sure that we’re precisely metering that into the system before we go ahead and release the refrigerant charge uh once that’s all set up the the refrigerant portion of the installation is complete we can go ahead and back off the valves and close everything up um and uh we can turn our attention to making sure that the system is powered correctly so on the wiring side we have to bring power to these units um so we want to make sure that uh the overcurrent protection is sized correctly so as we go from the panel to the unit we have a circuit breaker in place so we want to make sure that that overcurrent protection device is sized uh you know based on the name plate rating of our unit we want to make sure it’s properly labeled um so that we know that it is uh for our heat pump system and we also want to make sure that our conductors are sized correctly that we have the right wire gauge uh the right installation type um and that our conductors are compatible with uh the terminals on the overcurrent protection device the disconnect and you know and our unit itself um so all that needs to be done to make sure that we have a safe installation at the disconnect uh typically we going to have some means of disconnection between the power coming from the panel and the outdoor unit um that disconnect uh needs to be sized correctly for the you know the ampacity of our outdoor unit uh Sometimes some jurisdictions will require a fuse to disconnect like you see here um those fuses then also need to be sized based on the na plate rating of the unit itself um that disconnect should be in a place where it’s easy to reach um so in case of an emergency while the unit’s being serviced uh we can de energize it uh or we can make sure that it’s not re-energized um as you know we have a service tech working on that uh interior wiring needs to be landed correctly uh the biggest issue we see with uh this is just uh mistakes when it comes to which wires going to which terminal uh a lot of these units either have ABC or one two3 uh making the connection between the outdoor unit and the indoor unit uh so we really want to make sure that we’re following that color coding correct uh and that both the indoor unit and the outdoor unit have a proper ground so making sure that they’re grounded to a designated grounding lug uh is going to be important for operation right again just making sure that the communication and power cables you know are uh the same color or the same ones as we go between indoor and outdoor unit sometimes that gets a little bit messed up some jurisdictions will require a uh means of Disconnect at the indoor unit as well um so you see this is a three Poole disconnect switch uh that can be used uh for service or repair uh so for instance let’s say you have a multi-split unit and you have multiple indoor units and one outdoor unit and one unit it needs to be serviced of the indoors you could just turn the switch there keep the other units operating uh and then it’s safe to work locally on the unit that has has the issue um so again some jurisdictions require that um it is a good you know practice to have a means of Disconnect on the inside uh this way you can uh you know get properly service and and safely Service uh that indoor unit and then the last thing is uh controls um so know here we always advocate for uh wallmounted uh thermostats as opposed to uh handheld remotes uh just because when you’re utilizing a handheld remote for a ductless unit uh you know the return is every the uh the space temperature is being sensed at the return portion of that unit so it may not be accurately representing what the space temperature is because again of the the warm air rising to the top um so we would like to see um wallmounted uh controls that uh get a better representation of what the uh indoor temperature is this way we can really make sure we’re driving Comfort uh and uh you you may have to you know we also like to see Integrated Controls as well uh if you are uh using two different types of systems so we want to make sure we prioritizing the use of the heat pump and then we have our auxiliary uh coming in when needed and the last thing is going to be startup um so once everything is started up we want to verify we have proper voltage at the indoor and outdoor units we want to make sure we perform a heating and cooling check to make sure that we have uh proper operation there uh record system Supply and return temperatures to make sure that those temperature splits look good uh test the condensate drains these are all good things that we should be doing during the startup process so with that uh I do want to summarize what we talked about today and open it up for questions um the biggest thing with you know Heat pumps is you know reducing the building loads helps reduce the size of the heat pump it’ll improve the cost Effectiveness the performance the you know capacity uh we want to make sure that we route our refrigerant lines in the most direct uh uh path possible make sure they’re protected from damage make sure we have as little joints as possible uh we want to make sure we locate all of our units correctly both indoor and outdoor uh and then also just stay up to date with New Alternatives right there’s a lot of innovation happening uh in this uh in this industry so as we start to new systems you know out into the market you know keep up with that look at that performance data uh and make sure that we’re selecting the right uh product for our particular project so with that let’s open it up uh to questions if there are any hey Adam yeah there’s a there’s a couple questions can you hear me all right yes I can hear you all right um can you just speak a little bit about how um heat pumps work with existing duct work um so taking you know existing duct work in a house and and adding yeah so one of the things you have to pay attention to and I kind of alluded to it in the beginning uh when we were talking about um Central systems is that uh you know when you look at a heat pump system um you know those Ducks were sized for the flow rate and the discharge temperature that we are going to see uh on a conventional furnace or conventional uh you typically just conventional furnace or conventional air handler um so when we install you know these heat pumps you know we have to pay attention to our um our external static pressure how much pressure they can produce those fan motors uh and then also our discharge temperature um so um we you know most of the time uh when you’re doing this you may have to modify the duck work to ensure that uh we can provide the the right amount of flow because the external static pressure may not match up with what was in there previously um the temperatures obviously are going to be lower the discharge temperatures um so we need to make sure we insulate we seal those those that that duck work um but a lot of times it is going to require some sort of duck work modification either on the supply side to to make sure that we have good velocity to all the end uh end and end spaces or on the return side to make sure we have adequate return coming back from the space uh to ensure that we don’t have really high pressure uh across the unit uh but a lot of times uh you know duck work is an issue and even in just conventional system installation so most of the time it’s going to need to be evaluated and will probably be need to be modified great yeah and related to that uh with duct work um what are the typical duct sizes that are used for um ducted split systems are there you know specific um uh guidances that are F there does it VAR it’s gonna it’s going to vary um you know I mean it depends on how big the unit is right so the the larger the terminal unit the larger the um the um the outlet of that so you know either it could be know circular duck work it could be you know um a rectangular duck that that goes into a you know a a trunk line um so it is going to vary a little bit in terms of the the capacity one uh and then the the manufacturer and how they discharge that air but um you know typically you know for most spaces you’re talking you know five to six inch ducks for for most convention rooms um in some of the higher performance buildings you may be able to get away with 4in ducks it all depends on the load of the space so uh that’s really going to dictate how much air needs to get into the space in order to adequately heat or cool it great thanks and another one here um one uh one person indicates they’ve been told that their 10year old heat pumps are no longer level um however that releveling them at this point could adversely affect their performance do you have any comp comments on that no I mean that shouldn’t uh affect the performance uh releveling them I mean typically what they would do uh with those older heat pumps is there’s a process of pumping down the refrigerant um so you would pretty much store the the outdoor unit is usually large enough to be able to store all the refrigerant in the system inside of it inside of those coils um so they would typically just pump that unit down uh store the refrigerator in the outdoor unit cut the line set uh relevel It remake the connection uh again follow the evacuation charging all that stuff uh process but that shouldn’t um adversely affect the operation of the of the of the heat pump by trying to relevel it U but that’s something that I would advocate for just because again you’re not you can you may have run the risk of not getting proper lubrication to the compressor uh because if the unit is off a little bit um you know there know the oil level is going to be a little bit off inside the compressor itself yeah that’s really helpful thanks Adam um kind of related that you mentioned the refrigerant um one person’s asked uh around refrigerant leaks um you know is there concern for that being you know toxic in a household if there is a leak or or outside a leak and and how to address that yeah I mean so one of the when you look at refrigerants I mean one of the things that I mean it’s it’s changing a little bit but one of the things that was governing them is that they have to be non-toxic and non-flammable to go to residential applications um so you know there’s really is no risk of toxicity uh it’s more of a risk of volume um and for a single family home it’ll be okay uh for the most part because you have a lot of interior volume compared to the amount of refrigerant inside of a uh typical unit um but uh in larger multif family complexes where you have small apartments and a lot of refrigerant you know pounds and pounds and pounds of refrigerate tens of pounds um you know if there is a leak in a space you know it is heavier than air so it could displace the air in that in that section of of of room it doesn’t hasn’t really happened um but uh there typically isn’t much of a concern for refrigerants leaking into the space because you know they dissipate pretty quickly uh and there’s a lot of air in there it’s just going to cause a capacity issue what you’re going to notice is you know that the capacity you’re not able to heat or cool the space and the units are going to be running for long periods of time um you know or or you’re going to see that you know the Telltale know sort of uh ice buildup on the outdoor unit during uh during summer operation great yeah um and then I think this might be our last question um but uh can you just speak a little bit about when uh ervs are recommended in terms of heat pump systems and how those uh performances um Can can uh work together yeah no I mean Erv is I mean it’s a great option um you know especially when you look at your sizing right so when we’re sizing for you know our our heat pump system we have a a load that is going to be through you know con convection and conduction all the you know the losses through the structure and all of that and then we have uh losses that are going to be associated with ventilation right because we you need to remove air from the space and then we need to bring air back in uh and if we don’t uh condition that air that we bring back in that just becomes an added load on our equipment so if we incorporate an Erv or an HRV into our system design um that is going to um help reduce that load um so that you know the unit is going to deal with all the transmission losses through the structure um and the ventilation load uh in a large part can be you know sort of satisfied through the the Erv uh or the HRV as it’s operating so it’s a great uh combination uh when you’re designing a new building is to or a new home uh it’s it’s something that’s great to put in because you know one you’re getting you know good uh good uh ventilation uh but two you’re reducing that ventilation load on your systems great and I I there’s one quick question I I want to get to before we conclude here um uh can you install uh heat pump compressors in an unconditioned attic as opposed to the Out outdoors um so I have seen heat pumps installed in certain areas uh so I mean the only thing that is going to be I mean you need enough space you enough air flow so that what going to be important to ensure that uh there’s enough air getting into that space all right naturally through ridge vents and Sid Vents and all that because once you start to uh absorb heat or reject heat into that Airstream if there’s no way for that air to change over uh then the temperatures are just going to elevate or they’re just going to drop then it’s the capacity is going to have we’re going to have an issue with capacity there um because it’s going to be either getting too hot or too cold in the space so if there’s enough free flow of air to get in to satisfy the flow requirements of the unit um you can do that but it’s going to you know in a you know a two different season kind of area where we are you know or four seasons um you know it’s uh it’s going to you know perform well in one and it’s going to perform you know it’s going to be very poor during the summertime it’s going to be very hot in that attic um so you’re not going to get a good amount of performance there um it may be better in the winter because it’s shielded um but um most of the new units now you know can perform at very low ambient so I I wouldn’t be concerned with trying to absorb you know waste heat from from attic space you’re probably going to have more an issue with having adequate air flow that’s great yeah thanks Adam um and I think yeah that that brings us I think to the conclusion um of today’s presentation so thanks very much and Anna do you want to just remind folks where they can find the the recording and if um anyone’s looking for cus for’s presentation yep so we will be posting a recording on the Connecticut passive House website and we’ll email you all um a link to that also if anyone wishes to receive AIA or BPI credit we will be sending out a survey and an email to collect all of your info so look out for that in your inbox if you want to receive those CEOs great thank you and uh yeah thanks so much Adam we appreciate your expertise and uh time today yeah great thanks everyone I appreciate your time as well thank you by thanks and thanks again thanks again to the sponsors of energized Conneticut yep thanks by