Central heating systems have a primary heating appliance, typically a furnace, that’s usually located in your basement or garage. Furnaces consist of four main components: burners that deliver and burn fuel, heat exchangers, a blower and a gas valve.
Heating systems run on either gas or oil for fuel, but there’s also a hybrid system that can use both fuel types.
A furnace can work in conjunction with a heat pump or air conditioner with the use of an attached coil.
Most furnaces use a fan to circulate air to the rooms of the house and pull cooler air back to the furnace for reheating. This is process is referred to as forced-air heat. Separate ducts collect cool air to be returned to the furnace.
Cool air passes into the furnace, usually through an air filter, through the blower, then through the heat exchanger of the furnace, which is what warms the air. The warm air is then blown throughout the home.
A heat pump’s main advantage is it can cool and heat, so it can be used all year round. A heat pump pulls heat out of the outside air when it heats your home, but can be reversed to pull heat out of your house and cool.
A heat pump is also one of the ‘greenest’ ways to heat and cool your home because it is powered off of renewable electricity. This means lower electric bills and a reduction in your homes “green footprint,” or contribution to global environmental problems.
Advanced technology has led to two and three-stage furnaces and variable speed blowers. The term “variable speed” actually refers to the blower motor inside the furnace or air handler. They function using a built-in inverter and a magnet rotor. As a result, they are able to achieve greater efficiency than most AC motors. A variable speed blower motor runs at different speeds to control the flow of heated or cooled air throughout the home more precisely. This means not only a better balance of temperature and humidity, but also lower utility bills.
A two-stage furnace operates much more efficiently than a single-stage furnace. This type of unit has two stages of operation, full speed and half (or reduced) speed. They can typically run at a lower speed most of the time. It’s a much quieter option because it’s not forced to operate at 100 percent capacity. A two-stage furnace also creates less carbon dioxide emissions.