How Heat Pumps Work
Heat pumps are named appropriately. They pump heat from a cool area (the home’s interior) to a warmer area (the home’s exterior). In the winter they have the opposite effect, and heat the home.
Like air conditioners, they de-humidify the interior air, but they do a better job of it. This has two beneficial effects – they consume less energy and provide more cooling relief on those hot days of summer when the mercury starts to rise.
The prime difference between this type of climate control technology and conventional A/C units is that it moves heat rather than generating heat. Because of this, pumps can provide up to four times the amount of energy they conserve. Simplistic, but therein lies the magic.
Energy Efficient Climate Control
There are several varieties of pumps, the air-source (also called reverse cycle chiller), the ductless mini-split, the geothermal, and the absorption heat pump (the newest kind). For homes that heat and cool using electricity, the air-source model will reap energy savings of thirty to forty percent!
It should be pointed out that as the temperature drops during the winter, so does the efficiency. This is because there is less warmth in the exterior air so the unit has to work harder to squeeze out what’s available.
Heat Pump Features to Look For when Shopping
Who should consider a pump rather than an air conditioner? First, as mentioned above, a moderate, rather than extreme climate, is a good match. Second, is the existing system on its last legs? If the SEER rating on the old unit is low, a pump will pay for itself rather quickly (A rating of thirteen to sixteen is the average today; older units are as low as six!).
Also, new construction is a great time to install one, along with all the Energy Star rated appliances.
Here are some of the prime considerations to choose from:
- Two speed compressors – Unlike single speed compressors, two speed models can deliver only the capacity needed. When operating in the low speed mode, much less electricity is consumed.
- Compatibility with zone control systems – Two speed compressors play well with zone control systems, which keep different rooms at different temperatures using automatic dampers.
- Dual-speed or variable speed blower motors – These move air at the needed velocity, as opposed to single speed which blow at full speed at all times.
- High efficiency desuperheaters – Pumps integrated with a desuperheater use waste heat to heat water; it accomplishes this three to four times more efficiently than an electric water heater. Adding a tankless water heater as back-up subdues one more home energy hog.
- Scroll compressors – These use two spiral shaped scrolls to compress the unit’s refrigerant. They can produce up to fifteen percent more warm air than piston compressors.