What Size Furnace Do I Need for My Home?
Sizing Is About Heat Loss, Not Floor Area
Furnace output is measured in BTU/h. The right output matches how much heat your home loses on a design-cold day. A drafty, poorly insulated home of a given size needs more output than a tight, well-insulated home of the same size. That is why a professional load calculation — not a rule of thumb — is essential.
Why Bigger Is Not Better
An oversized furnace heats the house quickly then shuts off, cycling on and off repeatedly. This causes temperature swings, uneven comfort, more wear, and higher bills. A correctly sized furnace runs in longer, steadier cycles that deliver even heat and better efficiency.
Get a proper load calculation and correctly sized furnace from HeatLand.
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Related Questions
Can I just match the size of my old furnace?
Not necessarily. If your old furnace was oversized, or your home's insulation or windows have changed, matching the old size repeats the mistake. A fresh load calculation gives the right answer.
What happens if my furnace is too small?
An undersized furnace runs constantly and still cannot reach your set temperature on the coldest days, leaving rooms cold and the system overworked.
How do you calculate furnace size?
We perform a heat-loss calculation that factors square footage, insulation, windows, air sealing, ceiling height, and climate to determine the correct BTU/h output.
HeatLand Heating & Cooling has installed and serviced heating systems across Greater Vancouver since 1999. All gas work is performed by TSBC-certified technicians. Information here is general guidance — contact us for advice specific to your home.