A dual-fuel or hybrid system is the combination of an electric heat pump and a natural gas furnace. This system uses the heat pump’s outdoor condensing unit to heat your home using only electricity. The gas furnace comes into play when temperatures are below 35 degrees.
When using an electric Heat Pump as your primary fuel source, adding a gas furnace, as a secondary source can supplement your heating system when the temperature is colder than optimal for a Heat Pump. The fuel-efficient gas furnace can be used when it is coldest (usually below 35F). It will heat your home more efficiently and will have more capacity to bring your home to a comfortable temperature in less time. Once your home is at a more comfortable temperature, you can then switch over to your electric heat pump system and, if paired with a solar system, can utilize the energy efficiency of these combined systems.
http://earthcarefarms.com/hyzaar By switching to the high-efficiency natural gas or propane furnace during colder periods, the combined system (Heat Pump, Furnace & Solar) is more energy efficient, provides greater comfort, and has a smaller carbon footprint.
When it’s warm outside, your heat pump will reverse direction and act like an air conditioner removing warm air from your home.
Hybrid heating systems provide homeowners with an energy choice. As energy prices fluctuate, or, if the homeowner prefers the warmer air delivery of the furnace, the transition point between the two systems can be adjusted upward or downward. Hybrid systems also provide a redundant heating system should a problem arise with either one.
http://wishuponapar.org/plus/erraddsave.php Systems and Controls
Some systems you might consider are the Mitsubishi Temperature Control, Trane Comfort Control model 950 , Carrier, Bryant Heat Pump and furnace Evolution system with the Evolution Connex thermostat. All of these are compatible with the NEST thermostat. We can help you select the hybrid system and controls that will best suit your needs.