Does Bubble Wrap Actually Work as Window Insulation? Here’s the Deal

For those of us who don’t have high-efficiency windows, it’s pretty obvious our panes are a huge weak point for letting in cold in the winter and heat in the summer. To help mitigate that, some, like this person who posted on Reddit, have turned to bubble wrap as insulation.

It appears to be an affordable solution that’s easy to install. One commenter on the post wrote, “This is what they do in Korea. It doesn’t look great (and it’s not fun not having a window to look through), but it definitely keeps some heat in!”

On its face, it seems like a pretty good, frugal solution. But does bubble wrap as insulation actually work? Here’s what we found out.

Bubble Wrap as Insulation Hack

This hack is pretty simple: just cut a piece of bubble wrap to the size of your window and place the bubble side toward the glass. The person in the above post sprayed it with water, which caused it to stick to the window. You could also use tape to hold it there.

The Glass Doctor recommends using bubble wrap with large bubbles and little space between them.

Beyond insulation, the bubble wrap creates a pleasant soft light and obscures the windows for better privacy. On the downside, it makes it so you can’t see clearly from the window.

Will Bubble Wrap Work as Insulation on Windows?

In theory, yes, bubble wrap works as insulation. Adding airspace should help insulate. According to How To Go Solar, using bubble wrap as insulation improves their efficiency by 50% or more on single-glazed windows and up to 20% on double-glazed ones. Build It Solar also had promising results.

But Randy Huckstadt, an HVAC Expert with JustAnswer.com disagrees. “The problem with this whole concept is that it is not an airtight seal. Therefore, any air or any temperature making it through the window makes it right around the bubble wrap,” he says.

Another potential problem he sees with it is that if it’s freezing outside, spraying water on glass comes with the risk of cracking it, especially “because folks are typically doing this because they have poorly rated or single-pane windows,” he says.

However, others say that they have used this trick, and it does help. It’s a common practice in Korea, for example, where it’s called ‘air cap.’ The Institute for Basic Science in Korea states on its website: “If you want to make your home warmer in winter, you can cover panes of glass with bubble wrap [which] can be applied to glass if you first make the glass moist with water. They go on to recommend repurposing bubble wrap from a move, or from delivery packages.

Others in the Reddit post thread supported this method, too. One wrote, “We do this on some of our windows every year. They are single pane. It definitely helps. You can feel the difference one they’re up. If we’re having guests over we could easily take it down for the day.”

Window Insulation Alternatives

Another relatively affordable option as an alternative to bubble wrap is an insulation kit with an R-value rating for windows. These can typically be found at hardware stores and building centers. Here’s how to install them.

First, make sure your weather stripping is in good shape and check the caulk around the exterior and interior your windows for leaks. For a more permanent solution, try interior storm windows, which are more expensive but should last for decades.

Whatever you choose, remember that it will be far more effective if it makes a seal around the window.

About the Expert

• Randy Huckstadt is an HVAC expert with JustAnswer.com and is an authorized mechanic for Haward Service and Warranty Center.

Sources

• The Korean Institute for Basic Science, “Living in Korea.”
• The Glass Doctor, “DIY Project Insulate Your Windows with Bubble Wrap.”
• How to Go Solar, “The Truth about Bubble Wrap Window Insulation,” October 13, 202.
• Build it Solar, blog from Oct. 24, 2005.

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