How to Stop Cold Air from a Unused Fireplace

Clear fireplace cover to stop cold drafts of air.
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I've always been suspicious that the brick fireplace let in a cold draft. It's always more noticeable on a windy day, when I hear a slight whistle as I get closer to the fireplace.

I've tried a couple of previous fixes, which both would have been great, but just did not work for me:

  1. Fireplace Balloon - The reviews of this product were ideal and the price was affordable around $50. I was able to remove it for when I use the fireplace. I knew this solution wasn't a 100% tight seal, but still blocked most of the firebox entrance, out of view. Given that it was an old, the fireplace was dirty with soot. So as it turns out, trying to install the draft blocker was much more difficult than I had originally imagined and gave up.
  2. Fireplace Glass Door - This solution was certainly more decorative, but also served feature of blocking a majority of the fireplace. It featured a glass door and mesh screen, which is perfect for when the fireplace is in use. Even though I purchased the cheapest one, it still costed around $200. It was my bad, as it did not end up fitting since I had a decorative cover with a non-standard size. Measure first!

The Window Insulating Film for my Fireplace

This final solution I got manages to completely cover with a thin layer of plastic, but completely covers up the fireplace entrance which blocks the draft. It's actually a Window Insulating Film product, but because I have a solid (non-brick) fireplace, I figured this product would also work. And it only costs around $8 for 3-4 applications. This solution is a large piece of clear plastic (like saran wrap, but thicker and larger) with double sided tape.

Not that once this Window Insulating Film is applied, the fireplace cannot be used. The only way to use it would be to remove the plastic film. When you're done using it (or the cold season is over), you can then re-apply a fresh window insulation film.

Installation takes about 10-15 minutes, and is a very simple DIY project. All you need is a pair of scissors to cut the plastic film. Tweezers aren't necessary, but they're helpful in removing the double sided tape. A hairdryer to clean up and finalize the plastic wrap. And finally an razor to cut off excess plastic film.

  1. Clean the surface, because over the years, there's quite a bit of dirt and dust from the draft of the fireplace. Make sure the surface is dry before moving on.
  2. Apply the double sided tape around the edge of the fireplace entry. Do not remove the second side of the double sided tape until you're ready to apply the plastic film.
  3. Cut the films to the approximate size with a pair of scissors. If you can't get the plastic film cut to the exact width and height, you'll need to trim the plastic later anyways.
  4. Remove the second side of the double sided tape. This is where having tweezers might help in removing the first corner.
  5. Then apply the plastic wrap onto the double sided tape. Try to get the film as tight as possible with as few overlaps as possible. You can remove the plastic wrap to make adjustments as necesssary.
  6. Finally, take a hairdryer to remove and wrinkles or looseness in the film. By the end, the plastic wrap should be fairly tight.

This now completely blocks the fireplace entrance from any drafts. The plastic wrap itself isn't the perfect insulator, but will make a huge difference by blocking out fresh cold air from the outside. It will also prevent the "stack effect", which is hot air from inside the home leave through the chimney.

Ever since we moved into our home in Millbrae, our guests have commented our home is notably chilly. We felt it too, but wasn't sure what to do about it. Here's are the projects I've done to improve the temperatures inside my home. For those not familiar with Millbrae, it is a city in the SF Bay Area. The weather rarely gets to freezing temperatures in the winter and rarely gets to 100F in the summer. We never get snow.
  1. Results of Re-Insulating Attic in SF Bay Area
  2. How to Seal Power Outlets and Switch Airleaks
  3. Better Home Insulation by Sealing Gaps
  4. My Dog Door for Sliding Patio Door Is Drafty? Seal it with Insulation!
  5. Solving Water Intrusion into VERY SHORT Dirt Crawlspace
  6. Alternative to Messy "Great Stuff"
  7. How to air seal recessed lights on a budget?
  8. My Research on Vapor Barriers Before Meeting a Crawlspace Contractor
  9. How to Stop Cold Air from a Unused Fireplace
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