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How to Close off a Fireplace to Prevent Heat Loss
Just have a couple of quick questions. Jump to more Mr. Handyman quick answers about How to Close off a Fireplace to Prevent Heat Loss.
How to seal a fireplace to stop cold air from coming in?
How to close off a chimney permanently?
How to board up a fireplace for energy efficiency?
How to block a fireplace draft without removing the fireplace?
How to insulate an unused fireplace from the inside?
How to tell if your fireplace needs to be sealed?
How to seal a fireplace if you still use it occasionally?
How much does it cost to seal a fireplace?
Why choose Mr. Handyman to help seal or close off your fireplace?
The thought of a crackling fire on a chilly night is certainly appealing, it can also be a lot of work to consistently use your wood-burning fireplace. If you never have the time to enjoy your fireplace, it may be a good idea to close it off to save money on your home energy bills, reduce uncomfortable drafts, and reduce irritants like dust and pollen.
Should I Close Off My Fireplace Permanently or Temporarily?
If you plan on using your fireplace occasionally, you may decide to focus on closing the fireplace opening. This option is more accessible to remove when necessary. The drawback, however, is that by leaving the chimney clear, cold air can gather near your fireplace opening and possibly escape from blower vents, if present.
Open fireplaces are not as efficient as heating your home with a furnace or boiler, so consider making improvements in insulation or furnace maintenance instead of relying on a fireplace during cold weather.
Keep reading to learn how to close off a wood-burning fireplace safely.
When closing off your chimney, always make it clear to all home occupants that the fireplace cannot be used. Lighting a fire in a blocked chimney is a fire hazard and could lead to dangerous smoke inhalation as well.
How to Close off a Fireplace Opening
There are commercially available options. Many are plugs that can be cut to fit the exact dimensions of your fireplace opening. Some are removable, making it possible to use your hearth-style fireplace, say, for a special occasion (as long as the flue/damper hasn’t been permanently closed off—see steps below on how to do that).
You can also make your own fireplace insert. Plywood can be cut to the correct size to cover your fireplace and then backed with insulation. The plywood can then be painted or lined with a neat fabric to suit your room’s décor.
Here’s how:
- Measure the height and width of your fireplace opening.
- Cut a piece of ½-inch plywood to these dimensions.
- On the back of the plywood, use self-adhesive insulation to cover one side of the plywood.
- Decorate the front-facing side of your plywood with paint or create a textured effect with fabric. Cut the fabric large and staple or glue to the reverse of the plywood to keep edges out of sight.
- Press your new insulated fireplace cover into place. Voila.
Related Topic: Where Do You Put a TV in a Living Room with a Fireplace?
How to Close off a Fireplace Chimney
Many homeowners choose to take the additional step of closing off their chimney. This involves plugging the flue by sealing the damper. Flues can be round or rectangular, but simply looking at the opening at the top of your fireplace should be enough to determine what shape yours happens to be. This opening is called the throat or throat damper.
There are a few ways to close off the damper:
- Use silicone to fill in and seal the damper permanently. This is the most effective way, but it’s essentially permanent.
- Make a plug. Following the steps above, you can seal the damper with a similar DIY plug as the fireplace opening plug described. (Since it will be completely out of sight, you don’t need to decorate a flue plug.)
- Buy a damper plug. There are commercially available options designed for both rectangular and round damper openings. These can be removed, if necessary. Employing this option alone can also eliminate drafts and save you money while preserving the look of your open fireplace. Removable Inflatable flue plugs are available as well.
Save on Energy Year-Round by Closing Your Fireplace
Whether it’s a permanent seal or a temporary plug between uses, covering your fireplace helps keep warm air in and cold air out during the colder months. A closed fireplace does the reverse during the summer, so your air conditioner doesn’t have to work as hard. To learn more about how to close off your existing fireplace, contact your local Mr. Handyman for help. We experts at helping homeowners complete their home projects, both big and small. Give us a call or request an estimate today.
This article is intended for general guidance only and is not applicable to every situation. You are responsible for determining the proper course of action for your property and situation. Mr. Handyman is not responsible for any damages that occur as a result of advice and/or guidance derived from its blog content. Some Mr. Handyman services vary by location. Contact your local Mr. Handyman franchise for more information.
FAQs About How to Seal a Fireplace
For over 25 years, Mr. Handyman professionals have been helping homeowners repair, maintain, and enhance their space. We’re your one-stop solution for everything on your to-do list. That includes answering your questions about home repairs, maintenance, and improvements. Here are answers to some of your most frequently asked questions about how to seal a fireplace.
How to seal a fireplace to stop cold air from coming in?
To seal the fireplace, block cold air, and prevent heat loss, insert a chimney balloon or flue blocker inside the flue. Then, line the firebox with foam board insulation and seal cracks with fire-rated caulk. This reduces drafts and boosts your home’s energy efficiency during colder months.
How to close off a chimney permanently?
Permanently closing a chimney involves:
- Installing a chimney cap at the top to prevent water and debris
- Sealing the damper and flue with insulation
- Boarding up the fireplace or finishing it with drywall or decorative materials
This approach pairs well with methods for how to seal a fireplace from the inside. Consult your local building code to ensure your home remains compliant with all safety regulations.
How to board up a fireplace for energy efficiency?
To board up a fireplace, measure the firebox and cut a plywood or MDF panel to fit snugly. Add insulation behind the panel and seal the edges with weather stripping. This is a cost-effective solution that prevents heat loss and allows decorative customization.
For even better results, combine this technique with best practices for sealing the fireplace during the off-season. Learning how to board up a fireplace is a great step toward improving insulation.
How to block a fireplace draft without removing the fireplace?
You can block a fireplace draft by:
- Using a chimney plug or fireplace draft stopper
- Installing glass fireplace doors or a decorative cover
- Adding weatherproof caulking around the firebox
These options allow you to maintain the fireplace's aesthetic while improving insulation.
How to insulate an unused fireplace from the inside?
To insulate a fireplace from the inside, insert rigid foam board or mineral wool insulation into the firebox. Use fire-rated spray foam to fill any cracks and block airflow. This method is one of the best for homeowners asking how to seal a fireplace while keeping the structure intact. When done properly, it prevents heat loss and keeps indoor temperatures consistent year-round.
How to tell if your fireplace needs to be sealed?
Signs your fireplace needs sealing may include:
- Noticeable drafts near the hearth
- Rising heating bills
- Debris or soot falling into the home
- A musty odor coming from the chimney
If you’re experiencing any of these, it may be time to seal or insulate your fireplace.
How to seal a fireplace if you still use it occasionally?
Knowing how to seal a fireplace temporarily allows homeowners to adapt to seasonal changes without making permanent structural alterations. The simplest method is to use removable solutions like a chimney balloon, fireplace draft stopper, or magnetic fireplace cover. This is a popular option for homeowners who want to seal a fireplace in winter but still enjoy it occasionally.
Pro Tip: For seasonal fireplace users, sealing solutions should always be removable and fire-safe. Before lighting your next fire, be sure to remove any sealants and review these wood-burning fireplace safety and maintenance tips to keep your home protected.
How much does it cost to seal a fireplace?
The cost to seal a fireplace can vary depending on the method, materials, and condition of the existing structure. If you're trying to budget and wondering how to seal a fireplace affordably, start with a draft stopper or removable insulation as a cost-effective solution. Temporary DIY solutions, like a chimney balloon or fireplace plug, are typically inexpensive ($30–$100). Permanent solutions involving insulation or boarding may require more time, tools, and professional labor.
Why choose Mr. Handyman to help seal or close off your fireplace?
Whether you want expert advice on how to seal a fireplace for the off-season or how to close off a chimney permanently, Mr. Handyman delivers professional, reliable service. Our service professionals arrive on time, in uniform, and ready to get the job done right—the first time. Whether you need help with insulation, drywall, or custom solutions for your fireplace, we’re here to make your home more comfortable and efficient all year long.
Looking to seal your fireplace or need help with other seasonal home updates? Find your local Mr. Handyman here and let us take care of your to-do list.
