Switching to an entirely different type of heating source for your home can make economic, environmental, and lifestyle sense. The costs of fuels, such as natural gas, propane, heating oil, and electricity, have shifted dramatically over the past decade. Many new heating systems last 20 years or more, so with wide variations in fuel costs, long-term estimated operating costs and paybacks are not always reliable.
Electricity prices are the most stable and will probably continue that way. For homes heated with electricity, air-source or geothermal heat pumps make good sense because they can heat, as well as cool, your house efficiently.
A standard air-source heat pump is basically a central air conditioner with a few extra parts. The outdoor unit looks exactly the same as a central air conditioner. It is called a heat pump because it literally pumps heat out of your house (cooling mode) or into your house (heating mode) to or from the outdoor air around the outdoor compressor/condenser unit.
Among central heating and cooling systems, geothermal heat pumps provide the highest efficiency and lowest year-round utility bills. While geothermal heat pumps have much higher initial installation costs (due to the need to place loops, or tubing, to run through the ground or to a well or pond), the federal stimulus bill provides consumers (through the end of 2016) a 30 percent tax credit on the cost of putting in a geothermal heat pump system, which makes them much more affordable.
I use a portable heat pump in my own home/office for year-round savings. In addition to cooling the room during summer, it also functions as an efficient portable heater during winter.
The efficiency of a portable air conditioner is similar to a window air conditioner. Although this is less efficient than the newest central air conditioners, using one can still save money. By keeping just one or two rooms comfortably cool with clean air, you can set your central thermostat higher and save electricity overall. Use it in the dining room for dinner, roll it into the living room for television, and then to the bedroom for sleeping.
The heat pump edge
The primary advantage of installing a heat pump of any kind is they can be used year-round for both heating and cooling. This provides year-round savings, and shortens the payback period. In contrast, a super-efficient furnace gets used only during the winter and a central air conditioner only during the summer.