The first thing you should do when estimating a gas furnace size for your home is to find a trusted technician to undertake this important job. Modern furnace sizing requires a deep knowledge of how to match furnaces to a particular-sized home, while taking into consideration a constellation of other factors. The vast majority of homeowners aren’t equipped to do this.
Why Is Furnace Sizing So Important?
In the past, your furnace installer likely made an educated guess on what size furnace to place in your home, and then increased the recommended size “just to be safe.” In recent years, as the HVAC industry has become more advanced, this approach 
is being used less for obvious reasons.
A furnace that’s too small will struggle to heat your entire home during the winter, while an oversized furnace comes with its own set of problems. It tends to “short-cycle,” which means the furnace quickly arrives at the thermostat setting, and then shuts down. This process repeats at short intervals, stressing furnace parts, providing uneven heating, wasting energy and delivering inferior air filtration.
Industry-Standard Software
Most professional HVAC technicians will insist on performing a heating load calculation on your home, using the industry-standard software protocol, Manual J. This takes into account the size and layout of your home, as well as the number and type of windows in your home, the airtightness of your home and the quality of insulation in your home. Once the heating load calculation is done, the technician can recommend the right gas furnace size for your home.
Sizing Ducts
Nearly as important as choosing the right gas furnace size is making sure your home’s ductwork will be compatible with your new furnace. A qualified HVAC technician will inspect your ducts and recommend improvements, repairs or even replacement before installing a new furnace.
To make sure you obtain the expected efficiency out of your new gas furnace, it must be sized correctly. To discuss proper furnace sizing for your Twin Cities home, please contact Marsh Heating & Air Conditioning today.
Our goal is to help educate our customers in Minneapolis-St. Paul, Minnesota about energy and home comfort issues (specific to HVAC systems). For more information about gas furnace sizing and other HVAC topics, download our free Home Comfort Resource guide.
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