How to Increase the Energy Efficiency of a Fireplace

Fireplaces generate a lot of heat — as long as you’re standing right in front of them. Otherwise, they can suck all the heat right out of a room and send it up your chimney with a lot of smoke. But it doesn’t have to be that way. Here’s how you can increase the energy efficiency of your fireplace so it’s worth burning all that wood.

Improve Energy Efficiency of a Fireplace When Unlit

Chimneys are basically conduits of air up and out of a room. When a fire isn’t burning, warm air can still swoop up the chimney, wasting any of the energy used to heat that air in the first place.

Keep the damper closed: This is the first and most important rule of fireplace maintenance. The damper is a metal plate above the fire grate in the chimney. It should fit snugly against all four sides of the chimney so that when it’s closed, no air gets in or out. Over the years, a damper can warp, which lets air leak through. You can replace it, or you can install a chimney cap damper. The chimney cap damper closes the entire top of the chimney, which reduces heat loss when the fireplace is not being used.

Install fireplace doors: This will retain more heat — especially if you’re careful to keep them closed when the fireplace is not being used. However, most doors don’t close tightly enough to prevent air leaks. If you install them on your fireplace, make sure they’re sealed all the way around so that no drafts can get through. Close both the doors and the damper. The fireplace should also have a metal mesh screen that can be pulled close when the fire is burning. The screen will contain the logs and any sparks or embers that might shoot out from the fire, but will still allow some heat to get through.

Keep other doors closed: In a multi-story home, some homeowners find it useful to close the doors to upstairs or downstairs rooms while they have a fireplace lit. Since a fire in a fireplace sucks heat out of a room, closing the doors helps keep heated air in the bedrooms, bathrooms, and other rooms upstairs.

Have your chimney cleaned annually: And preferably by a certified chimney sweep. Nearly 7% of home fires are caused by creosote buildup in the chimney, so not only will keeping the chimney clean reduce the chance of fire, but the fire will burn more efficiently in a clean chimney. During the cleaning, have the chimney inspected for cracks and crevices, and seal any that are found to help improve indoor temperatures and save energy.

Energy Efficiency of a Fireplace When Lit

Turn down the temperature on the furnace. Since a fire can suck air out of a room, there’s definitely no point in overheating it. When you light a fire, turn the heat off or down.

Add a fireplace insert: The EPA recommends installing an insert in a fireplace to capture more heat and radiate it into a room, which prevents it from escaping through the chimney. Inserts must have a stainless steel liner that runs right to the top of the chimney to be safe. They use a heat exchanger to warm air, then circulate it. Most fireplaces convert only 15% of wood’s energy into useful heat, but inserts can increase the efficiency of a fireplace by a factor of five.

Burn dry wood: Oak, for example, burns hot and slowly, which will reduce smoke and ash, as well as the amount of residue that will build up on the inside of the chimney. Keep in mind that “wet” wood can mean wood that’s still filled with sap, as well as wet from precipitation. Fresh wood is likely to be wet, so burn aged, dry wood when possible. Use newspaper and dry kindling to help get the fire started, not something like charcoal lighter fluid. Never burn garbage, plastic, or pressure-treated wood, which can produce harmful chemicals when ignited. The EPA recommends ironwood, rock elm, hickory, oak, sugar maple, beech, ash, and several other hardwood tree species.

Replace the raised grate in the fireplace with an andiron grate: This will increase combustion efficiency. The more air that circulates around the wood, the more efficiently the wood will burn.

Purchase wisely: If you’re planning to purchase a new fireplace, choose one with heat circulation ducts built into the masonry. The ducts pull air from the room, circulate it around a metal firebox, and send it back, warmed, into the room. Built-in fans increase the flow of air and heat. Also, choose a fireplace that’s certified by the EPA as a clean-burning, energy-efficient appliance.

How are you planning to keep your home warm this winter? Feel free to share with us in the comments below!