Does your furnace capacity have what it takes to keep you warm this winter? While indoor comfort in cold weather is dependent upon several factors including outdoor temperature, furnace capacity is the biggest key in determining whether your household will be warm and energy-efficient all winter long. The capacity of a furnace refers to the amount of heat it produces (measured in BTUs), varies by make and model, and, for optimal performance and efficiency, must be matched to the specific heating requirements of the house.

Furnace Capacity Is Fixed

The capacity of a particular furnace is built into the unit. It can’t be increased or decreased. You’ll be living with that fixed heat output — whether it’s too little or too much — for as long as the unit is installed. That’s why it’s so important to get a heating load calculation by a qualified HVAC technician before installing a furnace in your home.

How Much Capacity Is Enough?

Fortunately, furnace capacity isn’t an x-factor. Furnace heating power is expressed by BTU output per hour. This figure is always included in the manufacturer’s specs and also shown on the unit’s ratings plate, usually permanently affixed to the inside of the furnace door.

The right capacity for your particular home can only be determined by a heating load calculation performed by a qualified HVAC contractor. Rough guesstimates or a “one-size-fits-all” approach to furnace capacity aren’t appropriate and lead to poor heating performance, diminished indoor comfort and substantially higher energy costs.

A professional heating load calculation includes a room-by-room survey of the home utilizing software that records input about characteristics including the amount and quality of insulation, number of windows, orientation to sun exposure, and structural air leakage. The software calculates the precise BTU per hour figure required to keep the house warm in typical winter conditions in your local climate. This figure can then be matched with a furnace that provides the necessary heating power — no more, no less.

For more on determining the proper furnace capacity for your home, contact the heating pros at Apollo Home Heating, Cooling Electrical, and Plumbing.