Does Window Insulation Film Work? [Inc. In Summer & Winter]

The main purpose of insulation film is to cool down your home on hot days and keep it warm during winter. Its ability to block out ultraviolet rays can also protect your furniture and fixtures from fading. With so many varying opinions on whether insulation film really works, we understand that you might find yourself asking the same question. Well, you've come to the right place, because we've scoured the internet for the best information on this query.

Window insulation film is effective, but only if it is properly installed. Properly installed insulation film means it's free from any gaps and bubbles. Proper installation can only be achieved with care and precision. There are different types of insulation film, so you should choose the one that suits your windows to achieve optimal results.

Insulation film offers many benefits to your home during the winter and summer seasons, ranging from energy efficiency to protecting your glass windows. We break down some of these benefits for you in this article, so keep reading to learn more.

Three new replacement windows with green trim on front of house, Does Window Insulation Film Work? [Inc. In Summer & Winter]

Window Insulation Film During Summer

Aside from blackout curtains, one way to keep your home cool in the summer is by installing insulation film. During the summer, insulation films help block excess heat from your windows while keeping the room bright and non-glaring.

At the same time, the film blocks out up to 99% of harmful ultraviolet rays, protecting your skin and preventing your colorful home furnishings from fading.

Some insulation companies offer promos during the summer, so if you want to save on installation costs, you should check with your local providers.

Living room with part of sofa in sunny day and white curtain

Check out this insulation kit from Amazon.

Window Insulation Film During Winter

Bokeh of city light behind the frosty pattern on the window glass

Similar to how it functions on hot, sunny days, insulation film can effectively trap the heat inside your home and prevent the cold from entering. Insulation film is a perfect DIY solution for old windows that do not keep drafts out and cause your electricity bills to soar.

Some of the benefits you can get from window insulation film include heat dispersion and lower electricity costs without giving up natural light.

Pros and Cons Of Window Insulation Film

Like any other product, window insulation film comes with a slew of advantages and disadvantages. However, that doesn't mean it's a product you should avoid. Take a look at our list to find out if insulation film will work for you.


  • It's low maintenance and will last a long time after installation.
  • Creates a slight tint to your windows for a boost of privacy and reduces the glare from the sun.
  • Insulation film kits are relatively inexpensive and come with almost everything you may need for installation.
  • Helps cut down utility costs by 40% to 60% by reducing the energy lost through windows.
  • Helps block up to 99% of UV rays to protect your skin from harmful exposure, as well as helping preserve the color of your furniture that's exposed to sunlight.
  • Acts as a protective layer in case the glass accidentally shatters.
  • Professional installers often offer seasonal promotions.


  • Installing film insulation requires precision to prevent bubbles and gaps. There's also a tendency for condensation to happen if the installation isn't airtight.
  • You can't entirely rely on the film to warm up your home because it's not as powerful as fully integrated heating systems.
  • You are only protecting one side of the glass surface, so the other side may still absorb heat and cold.
  • Certain window manufacturers warn users that their warranty will be voided if insulation film is installed on the windows. You may want to check with your manufacturer on this.

How to Properly Install Window Insulation Film

Wrinkled foil film covering the window untight

Before you begin the installation process, prepare your installation tools and materials. These include:

  • Window Insulation Kit
  • A pair of scissors
  • Measuring tape
  • Window tape
  • Hairdryer
  • A foldable ladder if your windows are too high

Once you have your materials ready, you may now begin insulating your windows with film. Do note that you can install the film either outside or inside the window, although, you may need to upgrade to a more heavy-duty film material if you're installing the film outside.

  1. Get the exact measurements of the window using the measuring tape.
  2. Wipe the window with a damp cloth to make sure the application surface is clean and smooth. You should also ensure that the window locks are snug and secure, as you won't be able to move the window around during the installation process.
  3. Apply the window tape to the windowsill, leaving a gap of at least one inch. Firmly press the tape to the surface to ensure it has adhered.
  4. Lay the plastic sheet that comes from the insulation kit on a flat, clean surface and trim it according to your window measurements.
  5. Peel off the paper from the window tape and place the plastic sheet on top of it, pressing each side firmly to prevent gaps from forming.
  6. Once you're sure there are no gaps for any air to pass through, then your insulation is all set!

Other Ways To Insulate Your Windows 

Stretch film in rolls. Wrapping film in rolls for window insulation

Believe it or not, there are a couple of other ways you can insulate your windows aside from using insulation film. Here are some of them.

Bubble wrap

Bubble wrap is often used to insulate greenhouses, but using it for your home is a great alternative if you don't have insulation film. Be sure the installation is airtight. Note that bubble wrap can make your window look fuzzy and hazy.

Check out this insulation bubble wrap on Amazon.

Removable magnetic window insulation

If you're not ready for a semi-permanent installation to your window, consider getting magnetic window insulation. It's usually made from vinyl and is easy to install. Plus, you have the option of moving it around if you're unhappy with the installation.

Check out this magnetic vinyl insulation on Amazon.

Rope caulk

While it's generally better for filling in small gaps along your windows, a good quality rope caulk can still offer a decent amount of insulation. You should apply the putty on both sides of the window to ensure optimal insulation.

Check out this rope caulk on Amazon.

Thermal curtains

For a foolproof option, grab a couple of thermal curtains for your windows. These special curtains are manufactured with a unique lining that blocks out light and excessive heat and keeps a room warm in winter.

Probably the easiest to maintain among the options on this list, thermal curtain can be tossed in the laundry for cleaning, so you can use them again as soon as they dry.

Check out these thermal curtains on Amazon.

How long does window insulation film last?

If it's installed correctly, window insulation film in the best conditions can last for up to 20 years. These conditions come from a wide selection of factors, such as the film's material, the condition of the window itself, and your local weather.

How much heat is lost through a window?

A house loses about 18% of its total heat via windows if the insulation is not good enough. Convection, radiation through the glass, and heat transfer through the window frame are all responsible for heat loss through the windows.

Final Thoughts

Three new replacement windows with green trim on front of house

It's unsurprising that you might find window insulation film a little daunting to use because of varying opinions regarding its effectiveness. Don't worry, because most window insulation professionals recommend it, and this is proven by the wide availability of film installation services.

Furthermore, insulation film is long lasting. If properly installed, it can last you for many years, allowing you to save money on energy costs.

Did you find this post helpful? Here are some other articles for you to check out before you go.

How To Weatherproof Windows With Plastic Wrap [A Step-By-Step Guide]

How To Seal A Window From The Inside

How To Get Windows To Leak Less Heat?

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