Central heating systems can be a near-necessity in certain climates. Depending on how cold it gets in the wintertime where you live, having central heating may be an issue of comfort or an issue of survival. When installing or replacing a central heating system in your home, you'll have a few different options to choose from, concerning both distribution and the source of your heat.
Distribution Options
Forced-air systems
Currently, the most popular method for home heat distribution in the United States is forced-air systems. These work on the same principles (and often within the same system) as central air conditioning. An HVAC (Heating, Ventilation, and Air Conditioning) installation first involves the laying of ductwork throughout your home. This includes intake vents that transport the cold air (from the floor) down to the heating source, and output vents that blow the warm air back into the room.
Forced-air systems can be easily integrated into an existing HVAC system for air conditioning, and can work in conjunction with furnaces, electricity, and heat pumps. Most new homes are outfitted with a forced-air system.
Radiant systems
You'll often find radiant systems in older homes. These use radiators to warm the air in a room or, less often, warm the walls and floors of the room directly. A boiler heats up water and sends it through a system of pipes. Sometimes, these are laid in concrete slabs under the floors, or they flow to radiator units in different rooms. Radiant systems are not commonly installed in new homes.
Gravity systems
In contrast to forced-air systems, gravity systems rely on cold air sinking through the floor ducts naturally, being transported to the heat source, and then rising through another duct.
Heat Sources
Furnace
A furnace system relies on burning a fuel source (e.g., natural gas or oil) that heats up colder air. The warmed air is subsequently redistributed throughout your home. This is one of the most effective systems, though it is not the most environmentally friendly thanks to its use of fossil fuels.
Electricity
Electric heating systems usually blow colder air over electrically heated coils and distribute it back into the house. The overall environmental impact of this is negative, since the source for the electricity the home uses is often fossil-fuel based. However, these systems are known for providing a lot of heat as compared to others.
Water
As mentioned before, water heating works with a boiler and pipes to circulate hot water throughout your home. The boiler is heated by gas or oil, so it's not entirely eco-friendly. This kind of heating is not generally used in newer homes.
Heat pump
Heat pumps work best in milder climates. Most heat pumps use refrigerant to extract heat from the air outside and pump it into your home using an HVAC system. Heat pumps can also work to cool your home. Though they are electrically powered, a good heat pump is one of the more environmentally friendly ways to heat your home.
So, that's an overview of your different options for central heating. Other guides provide more detailed and in-depth treatment of many of these options. If you are looking to save some money on heating bills and help the environment too, replacing old systems with newer models is a great place to start. Also, having an HVAC technician check your system for leaks and reliability can help make your home more efficient.