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What Filters Should You Use For Your Furnace?

It's a very common misconception, one that's well perpetuated by the filter manufacturers, that homeowners should use highly effective furnace filters if they want to take good care of their furnaces. In most instances, that couldn't be further from the truth. Provided your filter rack, the piece of ductwork beside your furnace that holds the furnace filter, uses a 1" wide filter which ~95% of the furnace filter racks in Calgary do, this applies to you.

You can't use highly effective, AKA "high efficiency", filters without at best expediting the furnace's degradation, and at worst causing parts to fail and leave your home without heat. The filter upstream of your furnace isn't there to filter the air for air quality for the occupants of the home, rather it's there to act as a protective screen for the furnace, only stopping things large enough to harm the furnace if it were to enter the furnace (chunks of wood, plastic wrappers, etc.). When we use highly effective filters, we reduce the amount of air flowing through the furnace which increases the temperature of the air leaving the furnace. The increase in outlet air temperature brings with it expedited degradation of most of the furnace's components.

The type of filter your furnace would prefer isn't pleated but rather uses a flat fiberglass matting and looks like it wouldn't stop anything past leaves and plastic bags. You should be able to read a book through it if your life depended on it. Again, provided your ventilation system requires 1" wide filters, these are the filters you should be using to take the best care of your furnace.

Now in the event that your ventilation system uses extra wide (4" and wider) furnace filters, which is becoming the norm with new homes and new furnaces, this advice does not apply. You extra wide filter folks can use highly effective filters without harming your furnaces due to the much higher surface area of extra wide filters, which is the benefit of having an extra wide furnace filter.

Blog provided by Jamison Furnace LTD


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