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  • Writer's picturemike marcinkiewicz

How Big Should my Furnace Be?

How big should my furnace be when it's being replaced? Across Mulmur, Shelburne, and the rest of Dufferin County many homeowners will ask their HVAC contractor this exact question. It is a natural response to ask for a bigger furnace because homeowners fear being cold in their home during the coldest days. However, a larger furnace may not be ideal for your home heating.

The most accurate manner to size a home furnace is to conduct a heat/loss calculation which takes into account your geographic region, wall insulation, amount of windows and doors, and the square footage of the space needed to be heated. However, this can take a few days to do and may need the assistance of a heating designer. Unfortunately, when a furnace breakdown and needs immediate replacement a heating contractor must rely and their experience and other supplementary factors. When your HVAC contractor is deciding on the size of the furnace they will take a few factors into consideration. Some include, the size of the previous furnace, the size of the ductwork, and the personal heating problems you may be experiencing. The goal is to size the furnace as large as it needs to be without going over. Many heating contractors are hesitant to undersize a furnace and usually will oversize it to compensate for their fear of having a cold house. However, this is a poor manner of sizing a furnace because it may not solve your heating problems and may create new ones. A confident HVAC contractor will determine if the existing furnace is short cycling, has a cracked heat exchanger, and if it's a mid-efficient furnace. They will use this information to pick the correct BTU input on the new one. For example, a heating technician determines that a 80,000BTU mid-efficiency furnace has been short cycling and discovered high CO levels in the combustion analysis. Using this information a technician will make the appreciate determination that the new furnace should not be bigger than 60,000BTUs. Amazingly, a new smaller but more efficiency furnace will use less fuel (propane or natural gas), run long enough to reach all corners of the home, and will last trouble free much longer. Therefore, next time you are in a position to have your furnace replaced, ask your HVAC contractor how confident they are in the size of the furnace they choose for you. Be sure they do not oversize your new furnace! If you need a heating expert with experience or you want a second option, give us a call at EMI Air Systems and we can help replace your furnace! Mike 437-343-0275

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