How much heat does a gas fireplace insert produce compared to an open fireplace?

A gas fireplace insert produces dramatically more usable heat than an open masonry fireplace — typically 70-85% efficiency versus just 10-15% for an open fireplace. This means a gas insert can deliver 4-6 times more heat to your room from the same amount of energy input.

Heat Output Comparison

An open masonry fireplace is essentially a decorative feature that actually removes more heat from your home than it provides. Most of the heat goes straight up the chimney along with massive amounts of your home's warm air — up to 300 cubic feet per minute gets sucked out of your house and replaced by cold outdoor air. During Calgary's -25°C winter nights, an open fireplace can actually make your furnace work harder to maintain comfortable temperatures.

A gas insert transforms that same firebox into a genuine heating appliance. Most gas inserts produce 20,000-35,000 BTU of heat output, which is enough to comfortably heat 800-1,200 square feet depending on your home's insulation and ceiling height. The sealed combustion system draws air from outside for burning and uses a fan to circulate room air over the heat exchanger, delivering warm air back into your living space instead of up the chimney.

Calgary Climate Benefits

In Calgary's extreme winter conditions, this efficiency difference becomes critically important. A quality gas insert can provide meaningful supplemental heat during those extended cold snaps when outdoor temperatures stay below -20°C for days. At current ATCO Gas rates of approximately $3.50-$5.00 per GJ, running a gas insert costs roughly $0.75-$1.25 per hour — significantly cheaper than electric baseboard heating and far more effective than burning wood in an open fireplace.

The sealed combustion also eliminates the draft problems that plague open fireplaces during Calgary's chinook events, when rapid pressure changes can cause smoke backdrafting into your home.

Installation Requirements

Converting from an open fireplace to a gas insert requires a flexible aluminum or stainless steel liner installed up your existing chimney ($800-$1,500), a gas line connection by a licensed gas fitter, and a gas permit from the City of Calgary. The existing damper is typically sealed, and the insert vents through the new liner system. Total project cost typically ranges $2,500-$5,500 installed, depending on the insert model, liner requirements, and gas line distance.

Professional Installation Essential

This conversion requires a licensed gas fitter and gas permit — never attempt DIY gas line work. The Safety Codes Officer inspection ensures proper venting, gas connections, and clearances. Many Calgary homeowners also appreciate that quality gas inserts continue operating during power outages if equipped with a standing pilot or battery backup system.

Need help finding a qualified fireplace contractor for your insert project? Calgary Fireplaces can match you with local professionals who specialize in fireplace conversions and understand Calgary's specific installation requirements.