Heat pumps can produce up to four times the energy they use, according to the
Department of Energy. (They're efficient
and look like R2-D2?) The stout appliances work by moving heat from one spot to another, rather than creating it.
Heat pumps can reduce electricity used for heating up to 40 percent, and efficient ones can save even more energy. A
high-efficiency or Energy Star heat pump may be quieter, easier to maintain, and better at controlling moisture than a minimum-efficiency heat pump. Plus, if you've improved your home's efficiency since the last time you purchased one, you might be able to purchase a smaller unit.
Every new heat pump is labeled with heating and cooling ratings; the higher the rating, the more efficient the heat pump. Cooling efficiency is indicated by the Seasonal Energy Efficiency Ratio (or SEER, which sounds downright wizardly), and heating efficiency is indicated by the Heating Seasonal Performance Factor (or HSPF). Use these ratings to compare heat pumps. Energy Star air-source heat pumps exceed federal efficiency standards by at least 10 to 20 percent; high-efficiency heat pumps are at least 30 percent more efficient. To maximize efficiency, make sure the ratings for the indoor and outdoor coils match.
If you live in a cold climate, take note: Don't buy a heat pump as a stand-alone heating system, because heat pumps are inefficient in sub-freezing temperatures. (A gas or propane furnace can serve as a back-up.)
1. To find out which heat pumps qualify for the Energy Star rating, use
the online database developed by the CEE/ARI (Consortium for Energy Efficiency and Air-Conditioning and Refrigeration Institute). You can search by SEER and HSPF ratings, manufacturer, heating capacity, and so on. It can look a bit confusing, so see the
quick guide to using the online database to get started. After opening the guide, in the left column, click
Section III - Sections of the Search Page for Heat Pumps for specific guidance.
2. Go to an appliance store or shop online to get an energy-efficient heat pump that fits your budget.
3. Hire a licensed heating and cooling contractor to install the heat pump.
Choose the right size. A heat pump unit that's too big for your needs wastes energy. A properly sized heat pump can control humidity better and may last longer. Ask your contractor for an exact heat-gain calculation (following ACCA Manual J procedures) to determine the proper size unit for your house. Make sure the contractor sizes the unit based on the latent and sensible cooling loads. Don't rely on rule-of-thumb estimates, as they tend to be inaccurate.
Consider buying a two-speed heat pump. A two-speed heat pump can run very efficiently at its lower speed during most of the season, while using its higher speed only during the hottest or coldest hours.
Locate the outside unit properly. Have the contractor install the outside unit in a cool, shaded spot about two feet from the north or east side of your home. Your heat pump will be happiest away from other objects and out of direct sunlight (which makes it work harder). To ensure proper air circulation, don't enclose the heat pump with a deck or shrubbery.
Check your duct system. If your duct system has leaks or disconnected portions, your heat pump won't be as energy efficient as it could be. Consider having your contractor check the entire length of your ductwork for leaks and seal any leaks with mastic-type sealant,
not duct tape. It's now possible for a contractor to verify if ducts are sealed by using a special fan to test duct system leakage before and after sealing. Also have the contractor check for and repair disconnected ducts, which are a common problem.
Insulate any ducts in unheated spaces to at least R-6.