As a home comfort provider, we’ve heard it all over the years when the subject of heat pumps comes up. “They blow cold air.” “They freeze up.” “They make funny noises.”
Here’s a favorite: if a heat pump could pump heat, how much heat would a heat pump pump, if a heat pump could pump heat? Guess what? A heat pump is not only an incredibly effective and reliable source of home (and business) comfort, but in our region, it’s one of the most efficient ways in which to heat and cool! Today’s heat pump is nothing like its forefathers.
Heat pumps seem to have a little mystery about them, but there is no real magic there. Inventor Robert C. Webber “accidentally” discovered the heat pump principle in 1948, when he burned his hand on the discharge piping of his freezer while he was trying to improve its ability to freeze. His desire to re-use that wasted heat was the basis upon what heat pumps are built today.
A heat pump is basically an air conditioner that can go in reverse. An air conditioner doesn’t actually make cold air; it removes heat from the air. An air conditioner removes the heat from the air in the house and it is ejected outside. Have you ever put your hand over the fan of your AC unit during the summer? That heat is what’s being removed from indoors.
During the heating season, a heat pump has a valve that reverses the flow of the refrigerant (freon), and heat is removed from outdoors and is ejected inside the home. Since we live in a milder climate, there is still available heat in the outside air even though it may make you feel cold when you’re outside in it.
Because a heat pump system “moves” heat versus generating heat, it can provide equivalent space conditioning at as little as one quarter of the cost of operating conventional heating appliances. In addition, with heat pump SEER (Seasonal Energy Efficiency Ratio) ratings available in the 23 range and HSPF (Heating Seasonal Performance Factor) ratings in the 10+ range, a properly designed and installed heat pump could cut your current heating and cooling bills easily in half. SEER and HSPF ratings are basically miles per gallon for your heat pump. The higher those numbers, the less it costs to operate.
There is a point (balance point) where the temperature is low enough outside that the system may require a little help, and that is when the backup heat begins to cycle on and off to help temper the air. This is either done by an electric heat package in the indoor section of the system or by a gas furnace. However, if your heat pump is properly designed, sized and installed, that “backup” will only be needed periodically during the coldest of days and nights.
Another heat pump mystery is why it ices up during the winter. As the heat pump uses refrigerant to absorb heat from the outside air when it is cold out, there is occasionally moisture in the air that is being pulled through the coil. On cold days, that moisture can freeze into layers on the unit. However, the unit has a built-in defrost mechanism. When it detects frost, the unit basically switches into the AC mode for a few moments, forcing heated refrigerant through the outdoor coil to quickly defrost it. For those of you who have a heat pump, that is the “swooshing” noise you occasionally hear, followed by a puff of steam coming off the melting frost. It’s all part of its normal operation and nothing to worry about.
Hopefully, this has taken some of the mystery out of one of the best ways to heat and cool your home. If a heat pump could pump heat, how much heat could a heat pump pump, if a heat pump could pump heat? Answer: All you’ll ever need—and at a cost to make the power company frown and your wallet smile!