How Improper Sizing Affects Your Furnace Efficiency

Furnaces are known for their ability to operate in a wide variety of different situations. It’s part of what has allowed them to dominate the heating industry for so many decades. However, that does not mean that you can just install any kind of furnace in any home that will fit it and expect it to work properly. There are a number of different factors that need to be considered when it comes to installing a new furnace in your home, one of which is the size of the system. Let’s take a look at what can happen when the furnace in your home is the wrong size.



“Bigger is better” is a pretty poor attitude to have when selecting a furnace. Furnaces that are oversized put out far more heat than the home is able to handle. This leads to the thermostat often shutting the furnace down before it’s able to complete its full heating cycle, a behavior called “short cycling.” Prolonged short cycling drastically increases the amount of wear and tear on the furnace, causing various parts to start wearing out and eventually leading to a full breakdown.


Undersized furnaces have just as many problems as oversized furnaces do. An undersized furnace cannot generate enough heat to keep the home in which it is installed at a comfortable temperature. So, it simply stays on for an extended period of time, trying in vain to keep the home warm enough to satisfy the thermostat. This causes just as much wear and tear as short cycling, and eventually the undersized furnace will break down just as surely as an oversized furnace would. If you want your furnace to last as long as possible, you need to make sure that it’s sized properly for your home.

Call Magnolia Plumbing, Heating & Cooling for comprehensive furnace services throughout Arlington, VA.