You don't have to know how to install heat pumps. You need to know what you want, and you need to know how to compare apples to apples when you get bids.
Proper sizing of any heating/cooling system is crucial to good performance and energy efficiency. Whether you're building new or working on upgrades for home improvement or electrification projects, here's some of advice for comparing heat pumps, primarily in heating climates.
Before you can compare anything, you need to know what you need, and where to find the information.
The Right Size Heat Pump Matters
FIRST: Get a heat loss/heat gain calculation done for the house on a room-by-room basis. In Canada, this is based on 'CSA F-280 (2012)', and in the US, this based on Manual J.
Do not rely on a rule-of-thumb, Btu/square foot estimate, or the capacity of existing equipment. Chances are, it wasn't sized properly, either.
The F-280/Manual J calculation gives you the important information about how much capacity the equipment needs to keep you comfortable, and how much heat needs to be delivered to each room.
Decide on what type of heat pump you're looking for:
- Air Source or Ground Source
- Ductless, Ducted, or Hybrid
THEN: Check out manufacturers' websites. You're looking for three key pieces of information:
- Heating Season Performance Factors (HSPF): this is the 'average' performance of the unit over the heating season.
- Coefficient of Performance (COP): this is the tested performance of the unit, and tells you how many units of energy it produces for each unit it consumes.
- Steady-State Rating: how well the unit performs at a low temperature.
If you are going for an air-source heat pump (ASHP), you want to choose from reasonably similar, high HSPFs. Use the COP rating for ground source heat pumps. Each heat pump has a steady state rating, which let's you know how much capacity it has to heat your house when it's cold out.
The 4 Essential Steps For Comparing Heat Pumps
- Make a short list of same-capacity units. Pro Tip: Choose ENERGY STAR rated units, they are in the top 30% of their class.
- Compare the steady-state ratings at –8.3°C/17°F (or -18°C/0°F for 'cold climate' units) for the units on your list. If you are in the northern US or Canada, and looking for an air source heat pump, you would be best served by a 'cold climate' heat pump that can perform well at very low temperatures. Pro Tip: The units with the higher ratings are the most efficient.
- Eliminate units that don’t have demand-defrost control.
- Select a unit with an outdoor sound rating in the vicinity of 7.6 bels or lower if possible.
Now you're making the most of your investment.
