Heat Pump Installation Guide: Sizing, Ducting, and Comfort
A heat pump is able to heat your home in the winter and cool it down in the summer. However, choosing the right one for efficiency isn’t everything.
If the unit is sized incorrectly for your home, or if the ducting isn’t properly supplying enough air, some areas of your house will be uncomfortable. Efficiency doesn’t matter if you don’t have proper airflow.
Here are some things to consider when looking at your home before having a new unit installed, and what to have tested when it is installed. Then, how to optimize your comfort after.
Learn About
- How To Size Your Home Correctly Before Purchasing Equipment
- Matching Your Heat Pump For Heating And Cooling Needs
- Duct Sealing And Other Considerations For Better Airflow
- Equipment Placement And Backup Heating
- Airflow Testing And Comfort Adjustments After Install
- Summary
How To Size Your Home Correctly Before Purchasing Equipment
You need to know what your home needs for heating and cooling before you decide what kind of heat pump to purchase.
Not only is square footage a factor, but the number of windows, amount of insulation, air leaks, shading, height of ceilings, climate, etc. There are many variables that go into determining what your home will require to stay comfortable.
By performing a load calculation, all of these factors can be calculated and come up with a proper size for your home. Load calculations are performed in most cases using ACCA Manual J. This allows your contractor to select equipment that meets your needs, rather than sizing based on your previous equipment.
What happens if my heat pump is too big or too small?
Your equipment may short cycle, causing discomfort in your home due to humidity levels. It may also fail to reach the desired temperature on the hottest days of summer or the coldest nights of winter. Although newer technology allows for variable speed equipment, it’s still best to size your home properly.
When talking to a local HVAC company about your options for a replacement, ask if they did a load calculation on your home. They may have simply sized your equipment based on what you had previously, which may be too little or too much.
Matching Your Heat Pump For Heating And Cooling Needs
Once a load calculation has been done, a local HVAC company such as United Heating, can see how your heat pump will perform compared to what your home requires. Using ACCA Manual S, the contractor can match the home’s loads to manufacturer performance data to select equipment that fits your needs.
Look beyond the heating capacity your heat pump can produce on a nice day. Since outdoor temperature affects the amount of heat your equipment will produce, it’s important to know how your equipment will perform during the colder months.
Ask your contractor about the following:
- What the heating capacity is of your equipment at the outdoor temperature in your area during winter months.
- Is your equipment going to cool and dehumidify your home on a hot summer day?
- What will the lowest heating output be if the outside temperature is higher?
- Do you want one ducted system, or multiple ductless units?
Have your contractor write the model numbers for the indoor and outdoor equipment on your estimate. This will allow you to research that specific system’s efficiency ratings, so you know what you’re purchasing when the unit is installed.
Duct Sealing And Other Considerations For Better Airflow
A new heat pump won’t fix bad ductwork. If your ducts are leaking, your rooms may not get enough conditioned air to feel comfortable.
ENERGY STAR reports that in a typical forced-air home, about 20% to 30% of the air moving through ducts is lost through leaks, holes and poor connections.
Some basics that your technician can inspect include whether the ducts are connected, any flex duct that may be pinched, ducts that need more insulation, blocked return air, or ducts that may need to be upsized. Any ductwork in non-conditioned areas should be inspected as well.
There are proper ways to size your ducts to make sure your equipment is getting the proper CFM (Cubic Feet per Minute). This is another process done with ACCA Manual D, which provides duct-sizing and airflow-design calculations for supply and return runs.
Make sure to have these questions answered about your ducts before moving forward with your installation.
- Will my existing supply and return ducts allow for proper CFM for my new equipment?
- Are there any areas that need to be sealed, repaired, or replaced?
- Are there enough supply registers and a proper return in my farthest rooms?
- Do I need to add more insulation to my ducts if they are located in an attic?
Make sure they can test the ductwork after repairs to ensure that it’s been sealed.
Having a larger unit won’t fix the lack of airflow, and can sometimes create more problems.
Equipment Placement And Backup Heating
Location can play a big role in your comfort as well. Make sure that your equipment will have proper clearance around the unit for serviceability, air, and drain lines. Follow the manufacturer’s recommendations, and keep in mind debris and snow that may collect nearby, plus the condensate and defrost water the unit releases. You may not want your unit in a tight spot or somewhere that will collect snow.
Make sure the unit isn’t located too close to windows, as that may be noisy, and that you can access the unit to clean it when necessary.
You also want to make sure your air handler is in a location that you can service and has a good way to drain condensation. Same goes for ductless equipment; placing them in strategic locations will blow air to more of your living space and away from furniture.
Backup heat can be used with your heat pump, and may be needed in colder climates, depending on the unit and home. Some newer units will continue to produce heat at lower temperatures, but it’s best to know what your equipment can do, and what you want it to do when it gets colder outside.
If you do have backup heat, make sure you know when it will kick on and what will control it.
Airflow Testing And Comfort Adjustments After Install
Your installation shouldn’t end once your new heat pump is blowing air.
Your technician should test your system by the manufacturer’s recommendations. Checking charge, CFM, and other readings that your equipment may call for. Static pressure can also be helpful to detect issues with your ductwork.
They should show you how to operate your equipment, heating, cooling, and backup if applicable. If your home has multiple zones, make sure they test each zone to ensure proper function.
When your install is complete, have them walk you through the following.
- Show you how to change temperatures and how to put your system in heat/cool.
- Show you how to change your filter and maintain your system outdoors.
- Tell you what is normal, and what your system may sound like when it’s defrosting, or cycling through different functions.
- Give you any information about your equipment, such as warranties, readings, etc.
There may be some fine tuning that you will need to do once your system has had a chance to run. Perhaps a room is colder, it could be an airflow issue, or your settings aren’t adjusted correctly. Bumping up your temperature may solve the problem, or it could be covering it up.
Identify which rooms are cooler, when it happens, and let your contractor know.
Summary
Installing your heat pump should be more than just a new piece of equipment. By sizing your home, matching your equipment, taking care of your ductwork, and making sure everything is tested, you can be happy with your new heat pump.
