Air to Water Heat Pump - Building Block Installations

Air to Water Heat Pump - Building Block Installations

Complete Air to Water Heat Pump (AWHP) installations can be costly. I believe a good way to get started selling this type of system is what I call "building block installations". This means using an AWHP when replacing any major HVAC appliance of the home. The idea is install the AWHP as a basic building block and build on it over time. You can also use this as leverage to retain your account. Maybe offer a discount on future updates. Let's assume that the home has two existing heat pumps for two different areas of the home. The situation is one of the compressors failed and requires replacement. This is a perfect time to offer an AWHP and move slowly into the electrification of our industry. Over time you can build on the basic system. The buffer tank should be included at the time of the AWHP is installed. It can be added later but could cause the AWHP to short cycle.

Here is a check list that is needed before you do the AWHP; (don't take shortcuts)
1. Where the homes heat loss and heat gain be reduced by air leak sealing, adding insulation, windows/doors if the homeowner has not kept up with this throughout his home ownership
2. Do a complete Manual-J het loss. This is particularly important to choose the proper size AWHP due to varying temperature supply water output at varying OD air temperatures. The AWHP may be larger than the existing heat pumps
3. Verify the AWHP is of a varying output style
4. In most applications you will need one OD unit even though there are multiple indoor units. One exception would be pretty large homes
5. If using air handlers you may decide to add electric back-up to the air handlers or use a boiler to boost water temperature when needed. (follow the manufacturers instructions)

Below is a drawing using an AWHP sized for the total needs of the home and replacing a single heat pump on a two heat pump home.

Eventually the second heat pump will fail, you add the second air handler with water coil instead of refrigerant coil, but not a second OD unit. You will have to get water lines to the air handlers.

Staying on this subject, no hydronic heat system, let's assume the homeowner wants to finish off his basement to usable space or is going to add a garage we have to option of adding radiant floor heat as another zone.

Another choice, if there is hydronic heat in the home already and the home also has 1 or multiple zones of air conditioning you can do the hydronic heat connections at the time of original installations. As the a/c units fail and need replaced add them on as needed. If an air conditioning unit fails and the decision is to use an AWHP connect the air handler to the AWHP. The hydronic system can be connected at the same time using the existing boiler as your back-up on extremely cold days. You will save when heating on milder days with the heat pump. The other option with an existing boiler and one of the a/c units fails is leave the hydronics system alone. The boiler can be connected to the AWHP next year or when the boiler actually fails. My choice would be to use the AWHP on milder days and extend the boiler life when not used as heavily.

I will add if your company is not into solar photovoltaic today is the time to consider this expansion to your company especially if you are doing new construction. This is a newer and quickly growing industry and can add an income stream to your bottom line.

Disclaimer:The information found on this website is for informational purposes only. All preventive maintenance, service, installations should be reviewed on a per job situation. Any work performed on your heating system should be performed by qualified and experienced personnel only. Comfort-Calc or it's personnel accepts no responsibility for improper information, application, damage to property or bodily injury from applied information found on this website as it should be reviewed by a professional.