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About Damien

Damien McCusker, Manager of Arpi's residential service division, has been working in the HVAC industry for 16 years and has hands-on experience in new home installations, furnace and air conditioner replacements, sales and residential service. He spends most of his spare time being an UBER driver, driving his kids to soccer practice and games.

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Furnace Sizing: Does Your HVAC Installer Take These Factors Into His Calculations?


Furnace Sizing: Does Your HVAC Installer Take These Factors Into His Calculations?Eventually, most homeowners will have to have a new furnace installed. If that time has come for you, you will need some basic knowledge to ensure that your installer will give you the heating equipment that best suits your home.

Furnace sizing depends on two things — the size of your home and the efficiency of your furnace. Technological advances mean that HVAC systems have improved significantly over the years, which means a smaller system can probably do the same job in the same space. Regardless, you want to ensure your furnace is not too large — because it will short cycle and heat inefficiently — or too small, which would mean it can’t do the job of heating your home.

There are many measurements that should go into furnace sizing. To make the process go smoothly, you should be ready to answer some basic questions: your square footage, your insulation rating, the type and age of your windows, and how comfortable your family usually is during the winter.

If your HVAC technician quickly decides that you need another similar model it should raise questions. An oversized furnace sets you up for issues down the road. Not only will you be extremely uncomfortable as the temperature varies rapidly, but you may have additional repair costs.

In Canada, we use a method specified in Canadian National Standard CSA F280. The procedure details how to calculate heat loss for a “design temperature,” determined by the house’s location. This temperature equals to one of the coldest temperatures your community may expect. The standard specifies that the heating system shouldn’t be more than 40 percent larger than what would be required to heat the house at that temperature. This allowance includes margin for error and allows a bit of oversizing. The sizing calculation recommends installing a furnace that will turn on for at least 35-40 minutes an hour during the coldest day of the winter.

When it is time for you to purchase a new furnace, contact Arpi’s Industries, Ltd. Started by Arpi Berdin a half a century ago, Arpi’s is committed to providing professional HVAC service within Calgary and throughout the surrounding province.

Our goal is to help educate our customers in Calgary, Alberta about energy and home comfort issues (specific to HVAC systems).For more information about furnace sizing and other HVAC topics, downloadour free Home Comfort Resource guide.

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