How can an air conditioner system provide both hot and cold air to a building or home environment? No mystery. Just a heat pump, an electrically powered climate control unit.
Air conditioners change the air in a room from hot to cool, with the help of a handler, coils and refrigerant. The refrigerant, a liquid that turns into gas, works like a sponge.
It soaks up the heat from indoor air and then through a compressor, transports it to outside where the heat is squeezed out into the air. The air leaving the air handler is much cooler than the room temperature, and a fan pushes that cool air through ducts and registers.
To warm a room, a furnace consumes gas, oil or electricity. As fuel is burned, the heat moves through ducts or pipes, then is blown out of registers, radiators, or heating panels.
Older systems use the heat they produce to heat water, which in turn heats the air in a building or home. These systems use a boiler to store and heat the water supply, which is then circulated as hot water through pipes embedded in the wall, floor, or ceiling.
This process can be performed more efficiently and cleaner by a heat pump than any other type of system, except when the outside temperature drops to 32 degrees and lower.
When the temperature drops, conventional pumps operate with less efficiency and the consumer pays higher rates.
Dual fuel heat pumps attach to an existing furnace and look and work like high-efficiency central air conditioners.
Both have a compressor that circulates refrigerant through indoor and outdoor coils. An air conditioner can move refrigerant in only one direction. But, a heat pump can force refrigerant in either direction, for heating one way and cooling the other.
During fall and spring, the dual fuel system still incorporates the furnace, but without using any burners, just its air distribution features. The heat pump sends hot refrigerant through the air conditioning coil within the furnace.
The furnace fan draws air from the home's cold-air returns and blows that air over the warm coils and then sends the warmed air throughout the house. In the summer, the heat pump reverses the refrigerant flow so cold liquid flows over the coil and cools a building, just like a conventional air conditioner.
In those mild spring and fall months in Northern cooler states, dual fuel systems provide inexpensive heat just as well as they do in the South. As the temperatures drop, the pump shuts off and automatically switches to supplemental gas heat for better efficiency.
During the coldest times, the fossil fuel furnace burns at its greatest efficiency. By combining the efficiency of a heat pump during its peak operating period with a high-efficiency gas furnace, oil furnace or boiler for the times when it is less efficient, a dual fuel system provides the greatest efficiency. A facility can be heated for less than if only one source of heat was used. Why?
Who should install a dual fuel system? People who already have furnaces in their homes and whose central air conditioners need replacing. People who want a heat pump to work in conjunction with their existing furnace.
Dual fuel heating provides a second heating system, which can save money, as dual fuel rates mostly remain stable year round. If a home-owner lives in an area in which fuel costs are low but electricity runs high, he may not see savings immediately, but, a dual-fuel system will save.
A thorough inspection from an HVAC service representative can evaluate whether or not the homeowner should install a dual system. If so, these systems provide the maximum efficiency, payback and comfort level on the market.