Does Window Insulation Film Really Work?

Allie Ogletree
Written by Allie Ogletree
Updated October 6, 2021
A mother with her daughter looking out the window
Halfpoint/iStock/Getty Images Plus via Getty Images

Insulating window film can help retain up to 55% of your home's heat in the winter

Get quotes from up to 3 pros!
Enter a zip below and get matched to top-rated pros near you.

Who hasn’t placed a hand on a glass window to gauge the temperatures outside? It comes as no surprise, then, that glass doesn’t exactly serve as insulation to your home. So, if your stunning (but drafty) windows of natural light take up more than their fair share of wall space, window insulation films can really make a difference in your home’s insulation. 

However, don’t just duct tape plastic trash bags around your windows and call it a job well done. Before you get started, here’s what you need to know about window insulation film.

How Does Window Insulation Film Work?

Window films effectively help prevent unwanted air from entering as easily through the glass, which would otherwise have no insulation whatsoever. But how do they work?

Window insulation film weatherizes your home by blocking cold air from entering and hot air from leaking through the windows in the winter, and vice versa in the summer. 

Much like its name suggests, an insulation film is a thin film made of polyester that is adhered to the interior side of your windows with adhesive tape. You simply clean your windows, cut the film to size, and apply it to your windows.

Cost to Install Window Insulation Film

Most window insulation films cost between $5 to $20 per square foot. Keep in mind, the features and quality of the films you choose will affect the cost. For example, the National Fenestration Rating Council (NFRC) verifies glare-resistant film for energy efficiency, giving it an NFRC certification rating; it will cost more than one that lacks these accreditations and features.

The Pros and Cons of Installing Window Films

A cozy living room with large windows and lots of plants
eclipse_images/E+ via Getty Images

There are many decisions that you have to make as a homeowner. Since windows play a major part in the temperatures inside your home, it’s no wonder that it can feel a bit confusing to decide on treating those windows

If you’re on the fence about whether to install window insulation films or to replace your windows, here are a few pros and cons to help you decide if insulation films are right for you.

Pros

  • Films are cheaper and only cost $5 to $20, compared to the cost of installing new windows, which ranges from $200 to $1,800 per window.

  • Window insulation film can mean as much as a 30% to 40% decrease in your utility bills.

  • Window films are one way to make your windows more energy efficient. You might be able to save up to 19kWh per square foot of glass on your energy costs.

  • If you purchase solar window films, not only will the films insulate your home, but they’ll also block harmful UV lights from entering and warping the furniture inside.

  • Films can help prevent shattered glass from spilling into your home.

  • Depending on your state and local programs, you might receive rebates for using window films, especially solar films.

Cons

  • Window films are best used on single-pane windows, as double-pane glass can fog due to the warmer and more insulated inner panel, despite limiting heat loss.

  • While window films can help insulate your home, the films won’t sufficiently protect you from hurricanes or other natural disasters.

  • Certain window manufacturers may consider window films as a void to their window warranties.

  • Like installing a screen on your phone, poorly installed window films can leave unsightly bubbles that are difficult to remove.

  • Based on your windows and installation skills, films can be difficult to install.

If you’re still unsure, or if you want to invest in higher quality, more efficient window films, a home energy auditor near you can help you determine what you need to do to enhance the insulation of your windows.

Installing Window Insulation Film

If you’re an all-hands-on-deck kind of person, then installing window insulation film may just be the perfect DIY project for you. All you need to do is follow these steps.

1. Go to the local hardware store and pick up a window film installation kit.

2. Clean the windows and let them dry completely before preparing the film. (Alternatively, you can leave soapy water or just plain water on the window to help the film stick to the window).

3. Measure and cut the window films, being sure to leave about one to five inches of the leftover film beyond the window frames.

4. Remove the adhesive strip from the back of the film (or have your tape ready if it doesn’t come with strips) and place them on the window frame.

5. Firmly and incrementally press the plastic film against the tape, starting from the top of your window and working your way to the bottom.

6. You might wish to use a hairdryer or Squeegee to keep air bubbles from becoming trapped under the plastic.

When to Hire a Professional Window Insulation Installer

Not everyone likes to install films. If installing protective films to your phone screens is challenging for you—or you don’t want the hassle of fidgeting with unruly plastic sheets—then you might want to hire a professional window insulation installer near you to do the job. 

Trained professionals install window film insulation to ensure it properly fits and covers the entirety of your windows. This will ultimately help you get the maximum insulation out of your films.

Need professional help with your project?
Get quotes from top-rated pros.