What Are Central Heating Systems and How Do They Work?

If you’re a current or soon to be homeowner, you probably have or are familiar with the term “central heating.” In fact, the majority of homes in the US have central heating installed.

Central heating systems heat homes by generating warm air or hot water in one location and then distributing that heat evenly throughout the home. Central heating systems can use a furnace, a boiler, or a heat pump to generate the needed heat. All of these units have one common piece, a heat exchanger. This is the heart of the device and without it a warm home would be impossible.

What are heat exchangers and how do they work?

A heat exchanger transfers heat created from your fuel source to forced air or water that will be distributed throughout the home to create a warm, comfortable space for you and your family. Heat exchangers can be made out of different materials, all of which have different heat transfer properties. These can include regular steel, aluminized steel, stainless steel, cast iron, or aluminum. The material used can affect the expected usable life and efficiency of the unit, and should be cleaned and inspected annually.

Equipment used in central heating systems include:

Furnaces

A furnace distributes warm air throughout your home through a series of ductwork and vents. The vents can be found in your floors, walls, or ceilings. When there is a call for heat by your thermostat, your fuel source is distributed through one or more burners where it is ignited. The heat generated by the burner(s) is pushed through the heat exchanger to heat it up. As this process is happening, the blower motor in the furnace will come on and begin to circulate the air in your home over and through the heat exchanger to warm it up as needed before it is distributed throughout the home. Any dangerous fumes or exhaust gases are vented to the outside either though a standard chimney or PVC pipe which is used on newer, high efficient units.

Boilers

A boiler distributes hot water throughout your home through a series of piping and radiation. The radiation can be cast iron radiators, wall mounted baseboards, or in-floor radiant tubing. When there is a call for heat by your thermostat, your fuel source is distributed through one or more burners where it is ignited. The heat generated by the burner(s) is pushed through the heat exchanger to heat it up. As this process is happening, the water in or surrounding the heat exchanger is heated up to a pre-determined temperature and then pumped through the piping and radiation to evenly distribute the heat throughout the home. Any dangerous fumes or exhaust gases are vented to the outside either though a standard chimney or PVC pipe which is used on newer, high efficient units.

Heat Pumps

A heat pump is an air conditioner that can reverse its process to extract the warm air that is outside your home to heat your home. The warm air is distributed throughout your home using a series of ductwork and vents similar to that used by a furnace. In the summer, air conditioners remove the warm air from inside your home. In the winter, it does the opposite, bringing in the warm air from outside. This is done by circulating refrigerant through a series of evaporator coils. During the heating season the refrigerant absorbs the warm air that is outside the home, which is then extracted from the indoor coil by circulating the air in your home through it by using a blower motor similar to that in a furnace. Heat pumps use electricity, and may require a supplemental source of heat to satisfy the demands of the home depending upon the climate in your area. They do not require venting.

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