The Importance of a Properly Sized Furnace

by James Florence


When purchasing a new furnace, bigger isn’t always better. Photo: Kelly Plumbing & Heating (2014)

When it comes to installing a new furnace, many homeowners assume that bigger is better. However, according to Kent Penning, owner of Cold Craft, Inc., this is far from the case. “Some people assume that more power is better with furnaces, but it’s actually more important to choose one that’s properly proportioned to your home,” he explains. “If anything, it’s better to go with a smaller unit—it’ll do the same job and last longer than an oversized one.”

Rather than making a home warmer and more comfortable, an oversized furnace tends to have the opposite effect by causing “short cycling.” In this situation, a furnace will turn on for short runs of five to 10 minutes at continuous intervals throughout the day, resulting in rapid temperature fluctuations and increased energy usage. In contrast, an appropriately sized furnace will stay on for longer periods (usually 20 to 40 minutes) at fewer intervals. Because it warms the house gradually, the temperature is maintained over a longer span of time, so the system doesn’t have to keep turning on and off. In addition to being more economical in terms of energy usage, this slow and steady process keeps the climate of the home more consistently comfortable.

Before making a purchasing decision, consult a licensed HVAC professional—he or she will be able to help you choose a unit that’s correctly proportioned to your home’s heating needs.

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