The size of a home does not dictate the furnace British thermal unit output needed to heat it properly or efficiently. Several factors must be considered when deciding on the correct furnace BTU output for a specific home. BTU calculators available online, such as Calculator.net, can assist in the process.
Home square footage, ceiling height, insulation condition and local weather patterns are some of the variables that can affect the choice of a furnace. Furnace efficiency should also be considered because a high efficiency furnace, produces more heat than a lower efficiency model with the same BTU output. A high efficiency furnace may cost more up front, but should recover its expense over time.