New, very high efficiency heat pumps now promise a way to drastically reduce the use of natural gas for home and business heating in many instances. New high-efficiency ductless heat pumps (DHP) may revolutionize the way people heat and cool their homes in the near future, dramatically reducing heating and cooling costs while driving down the use of fossil fuels.
Also called “mini-split heat pumps,” DHPs install easily (often in less than a day), and can both heat and cool homes, offering a big advantage over gas furnaces that are limited to heating only. With natural gas prices going up rapidly in some locales, DHPs are rapidly gaining consumers’ attention. So what kind of savings can they offer?
PG&E, the utility that serves a large part of northern CA including the San Francisco Bay Area, has announced new natural gas pricing that averages about $1.45 per therm for residential users. At this rate, early estimates indicate that the highest efficiency ductless heat pumps units are competitive with natural gas when electricity costs are about $.18 per kWH or less. Because ductless heat pumps can have an initial cost as much as 30 percent less than a new natural gas furnace in smaller homes, and with the added ability to cool the home at high efficiency, ductless heat pumps may rapidly move to replace old gas furnaces in residential homes and apartments up to about 1200 ft2 or even larger.
The recent introduction of Mitsubishi’s H2i MSZ-FH model line shows that certain mini split models can now heat a residence at 100 percent rated capacity down to a 5 deg F outside temperature, with effective operation down to 15 degrees below zero. This makes DHPs an ideal option in many locales such as the Pacific Northwest, Northern California, and other temperate climates. By keeping older natural gas systems as back-ups, DHPs may take a role as a primary workhorse, providing high efficiency heating and cooling for virtually every type of climate zone in the USA.
The ability to operate at very low temperatures makes DHPs performance in more temperate climate areas very impressive indeed. It leads some contractors who specialize in DHPs to recommend them for larger homes as well. Andrew Hiemstra, of Vanstra Contracting in Oregon, relates that “When customers with larger homes ask if they should install two heat pumps instead of one, I tell them to install one unit first and see if it can handle their needs by itself. These products are so efficient that one unit can often handle a customer’s larger home requirements in this climate.”
The State of Oregon, recognizing the advantages of new DHPs, has offered significant tax credits to stimulate DHP installation. Tax credits run up to $1050 per installed unit, with higher efficiency incentives already published for future products. Certain Oregon localities offer additional incentives of up to $500 per unit when they replace resistance coil electric heat in baseboards or ceilings. Other states are beginning to follow suit. The State of Maine has adopted similar incentives.
DHPs promise big reductions in natural gas use when they are combined with solar arrays and net metering schemes. Combining solar panels and DHPs offers the best of all worlds for consumers, since the net cost of powering the heat pumps plummets when solar energy is the source of their electric power demands. In this way, natural gas is completely displaced as the primary fuel for heating, as well as the feed stock for electrical power generation in power plants.
While DHPs are available in multi-headed units, where one outdoor compressor drives up to four indoor heating and cooling units, contractors are finding the best efficiencies in single head units (one outdoor compressor and one indoor unit). As a result, they believe that multiple single head units may offer superior performance to multi-headed ductless heat pumps.