Choosing the Right Size Heat Pump for Your Home
Heat pumps are energy-savers and can operate effectively in a wide range of micro-climates. These dual-purpose appliances make functional and affordable additions to just about any type of HVAC system, and in places that don’t experience temperature extremes they may be able to handle the entire heating and cooling load.
However, heat pumps are an efficient and sensible choice only if they are properly sized. If you buy and install a heat pump that is too powerful or too weak you will undoubtedly live to regret it.
So how does one go about choosing the perfect size heat pump? By hiring an installation company that uses a method called Manual J, which we will explain more fully in the next section.
What is Manual J and How Does it Work?
Manual J is the standard procedure used by HVAC professionals to evaluate a home’s potential for heat loss in cold weather and heat gain when it is warm.
Once they know what your true heating and cooling needs are, then and only then will HVAC technicians be able to make a correct determination about what size heat pump you actually need.
The parameters HVAC installers use to make Manual J-based recommendations for your home include:
- Average daily temperatures in your region.
- Your home’s architectural design and siting (its size, shape, number of floors and specific location).
- The amount of heated or cooled air your home is likely to leak.
- The number of windows you have and where they are installed.
- The thickness and comprehensiveness of your insulation.
- The number of people who live in your home.
- The amount of heat added to the home by lighting and appliances.
- Input from you and your family about the temperature ranges you find comfortable.
When your installer has this information he or she will be able to make detailed, accurate calculations about your true heating and cooling needs, making it easy to identify the size of heat pump you require.
Pump it Up! But not too Much or too Little
If you install the wrong size heat pump, you’ll either be too hot or too cold most the time (if it’s too small) or you’ll be waste money producing more hot or cold air than you really need (if it’s too large). The inefficient cycling patterns that result will put undue stress and strain on your heat pump, likely causing it to wear out or break down sooner than expected.
For these reasons you should be very careful about making sure you purchase the right size heat pump. Don’t hire an HVAC company to consult with you on this issue unless you can verify they will be using Manual J standards, without which they will likely be making it up as they go along.
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