A quick primer on heating systems

Around here, most homes have either a boiler or a furnace. It’s a bit surprising how often people will mix up the terms; they really are not interchangeable. While we don’t expect you to have an exhaustive knowledge, we do hope that after reading this you will be able to tell the difference between the two.

Furnace- A furnace heats air that is distributed using a system of ducts. The ductwork is usually hidden in the walls of the house. There are supply vents in each room as well as several return vents throughout the house. When your furnace is on, it is blowing air in and sucking air out at the same time. If your house has central air conditioning the same ductwork is used for your cooling system.

Pro: Furnaces are cheaper to install.

Con: Blowing air through a house can spread allergens and negatively impact the air quality.

Boiler- A boiler heats up water and a network of pipes distributes the hot water (or less commonly, steam) to radiators or hot water baseboards throughout the home. Some homes, with boilers, are retrofitted with ductwork (generally in the ceiling) for air conditioning or you might see wall mounted air conditioning units.

Pro: Boilers tend to heat a room more evenly and more quietly (though you can sometimes hear water/steam knocking in old radiators).

Con: When a boiler breaks, it can be more expensive to repair than a furnace.

Boilers and furnaces are both typically heated using gas or oil though there are electric units available for each, but the cost of electricity makes these less desirable options in the Northeast. According to energy.gov, 49% of homes heat with natural gas, 34% with electricity, 6% with fuel oil.

While the vast majority of homes around here have either a boiler or furnace, there are some other heating systems to be aware of.

Electric resistance heating (baseboard) - Electric baseboards transfer electricity into heat. These systems are inexpensive to install but are very expensive to run and in our area are generally confined to use as supplemental heating (i.e. a finished basement).

Heat pumps- There are three types of pumps - air to air, water source, and geothermal. These systems collect heat from the source and move it inside the home. While air to air is the most common, geothermal is more efficient (though expensive to install). Heat pump systems can significantly reduce electricity use compared to electric resistance systems.

Another method of heating that you might see in this area is radiant heating, which transfers heat from a hot surface to the people and objects in the room via infrared radiation (like the heat that comes off a hot stove element). It’s an efficient system as it reduces heat lost in the ducts of forced air systems. The radiant heat units can be electric or air-heated but hot water systems are the most common.

Unless you are building a new home you will likely inherent a heating system and it’s unlikely that you will change it, but it’s useful to know about the different options, if only to ensure that you never mix up a boiler and a furnace again.