What Size Furnace is Right for My Home? A Question from Funkstown

When it comes to your Funkstown home’s heating equipment, the right size is very important. If your furnace is sized correctly, you will enjoy a high level of indoor comfort, which you should. However, an incorrectly sized furnace may result in many cold spots in your home, an overworked furnace, or higher utility bills.

An undersized furnace will turn off and on frequently, which is called short cycling. Short cycling can lead to moisture in the system, causing less efficiency and damage to equipment from accumulating moisture in the heating system. The constant cycling adds to wear and tear on equipment, too. An oversized furnace may not be able to keep up with the demand for heat during the coldest days. The furnace may be constantly running and unable to keep up – adding to higher utility costs. So size really does matter when it comes to selecting the right heating equipment for your home.

But a big furnace does not mean it is right-sized. Have you ever seen a “five-way” gravity furnace? It was manufactured in the mid-1900’s and took up a lot of room – as much as half of a basement – while being extremely inefficient. The key here is efficiency. A furnace that works right is sized to the space it is heating, which does not include attics, crawlspaces, or uninsulated rooms (porches, mud rooms, etc.).

A furnace must make efficient use of its Btu’s, which is abbreviated for British thermal unit. Btu is used to measure a furnace size. Furnaces are often rated by input Btu, which is the amount of energy consumed when running. The output Btu may be different based on the system. And output Btu is the best way to select a furnace, since this is the actual heating capacity.

When sizing a furnace, the first thing to do is to determine the inside space that will be heated. If you are looking to heat your home, you can measure the square footage of each room (multiply width by length). The rooms should include bathrooms and hallways but exclude attics and crawlspaces. Add up the totals and match up the Btu output to the total square footage. If you aren’t sure of your calculations, call a qualified heating and cooling contractor.

There are many factors that go into heating a home and today’s energy efficient furnaces give homeowners many more choices. Whatever furnace you choose to purchase, make sure you do your homework and hire a qualified professional HVAC contractor to determine the best size furnace for your home.