How to Insulate a Fireplace and Chimney (and Why You Should) 

Insulating your fireplace and chimney can improve energy efficiency while the fire is hot and reduce air leaks when it’s not. Homeowners looking to save money by supplementing their central heating with a roaring fire should look at safe ways to insulate their fireplaces.

The Benefits of Fireplace Insulation 

Homeowners who love a crackling fire can reduce the inefficiencies of their fireplaces. As much as 90% of the heat produced by a fireplace goes directly out the chimney. Even when your fireplace isn’t in use, it may cost you. Leaks in the fireplace door (if present), vents and fans, and the chimney can allow heated air to escape in the winter and let hot air into your home during the summer months.

That’s where insulating your fireplace pays off!

Related Content: Woodstove and Fireplace Safety

How to Insulate Your Chimney and Fireplace 

The three best ways to insulate your fireplace and chimney focus on reducing air leaks. Each component of the fireplace offers an opportunity to restrict heat loss and save money.

Insulating a Chimney Liner 

Also known as a flue liner, a chimney liner is a long, flexible tube that connects the top of your fireplace to the top of your chimney. Chimney liners help protect your home from the heat and smoke produced by your fire and reduce the risk of smoke leaking through small cracks or seams in the chimney itself. Liners also lower the chances of fire by adding another layer between hot air and spark and your home’s wooden structure.

Most chimney liners are made of flexible stainless steel, which means they aren’t effective at retaining heat or keeping cold air out. Insulating your chimney liner offers a few perks, such as:

  • Reduced risk of moisture buildup caused by extreme temperature differences
  • Hot air staying hot longer, ensuring gases and smoke travel out of the home safely
  • Reduced heat loss when the fireplace and chimney are not in use

Chimney liner kits are the best way to safely insulate your chimney. There are several methods available, including wraps and blankets.

Insulate Your Fireplace Door 

If your fireplace has a glass or metal door, check to see if the seal is cracked, broken, or missing. Faulty seals allow cold air to seep into your home when the fireplace is not in use. It can also allow smoke and carbon monoxide into your home when a fire is lit, putting your health at risk. Inspect your door seal and replace it if it shows any sign of wear.

Insulating the Chimney Walls 

Like all of the exterior walls of your home, insulating your chimney walls helps prevent air leaks. Be sure to leave an air gap between the fireplace itself and your chosen insulation to avoid combustion. Insulation should be focused on the wall cavities between studs, never against any metal component of the fireplace itself. You may also add a barrier of fireproof material over the insulation to further separate possibly combustible materials from the heat source.

Always follow local guidelines and building codes where applicable.

Can I Use Spray Foam Around a Fireplace? 

Never use spray foam in a chimney, flue, or chimney liner. Most spray foams are flammable and increase the risk of fire. Some types of spray foam can be used on exterior chimney walls, but always place a fireproof material over the insulation and leave plenty of room for an air barrier between the chimney wall and fireplace wall.

Don’t Forget to Close Your Damper! 

One of the most effective ways to reduce drafts is to keep your damper closed when your fireplace is not in use. This keeps cold air from getting inside your home, causing cold spots and even causing your heating system to turn on more often. Make closing your damper a part of your routine when putting out your fire.

Make this Winter Cozier than Ever 

Insulating your fireplace is just one way to keep your family more comfortable when the mercury drops. Trust your locally-owned One Hour Heating & Air Conditioning technicians to provide expert maintenance and emergency repairs on time and at a fair price. Request an appointment today or call (800) 893-3523 today!