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How to Insulate Your Windows to Keep Heat Out

Written by Ashlyn Needham , Edited by Gianna Cappuccio

Published on July 2, 2024


How to Insulate Your Windows to Keep Heat Out

Learn how to insulate windows for winter and summer months with these cost-effective DIY and professional-grade methods.

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When extreme weather arrives, the need for comfortable indoor temperatures rises. We all love open windows that allow natural light and fresh air, but insulating your home is crucial for maintaining comfortable temperatures year-round – not to mention energy efficiency.

Luckily, window insulation is an easy home improvement task. Re-caulking your current windows, applying weather stripping, or changing window treatments are just a few methods that can be DIY and cost-effective.

Hire a local pro to repair or replace your old windows

Key takeaways

  • Film is the cheapest insulation method for windows. This common household staple effectively controls the hot or cool air that enters your home. 

  • Weatherstripping is the best insulation for summer because it effectively keeps air-conditioned air inside and blocks hot air from coming in. 

  • Re-caulking your windows is the best insulation method for winter since it closes off gaps that may let the inside air out or the cold weather outside in. 

  • Window insulation is great for keeping your home comfortable and energy-efficient and decreasing energy bills.

7 ways to insulate windows

While some home improvement projects require the expertise of professionals, insulating windows can be done DIY to prevent heat loss. Professionals come in handy and are recommended if you have to insulate taller windows, have many windows to insulate, or are upgrading to new ones entirely. But, for the most part, all of the insulation methods can be done yourself over the weekend, so you can be well on your way to saving money on energy bills. 

If you’re looking to make your home more energy efficient or prepping for the change in weather, here are seven window insulation methods to try per season or year-round.

Add window insulation film

Window insulation film over a winter scene

  • Best for: Any season

  • DIY difficulty: Low

  • Cost: $15-$30

Window or plastic film is cut to fit your windows before being steamed with a hairdryer to smooth out the wrinkles and shrink them into place. Window insulation kits prevent air from entering through the glass by acting as a screen or second window pane. 

Here are the steps to install a window insulation kit with film:

  1. Clean: Remove any treatments or blinds and clean the windows entirely (pane and trim) to remove dust. Use a wet rag and soap to ensure the window stays wet while applying the film.

  2. Cut and measure: Take the film out of the kit and hold it up to your window to measure (adding five extra inches onto all sides that will shrink later) before cutting with scissors. 

  3. Attach tape: Affix double-sided tape to the edges of your window frame.

  4. Paste film: Take your cut window film and work from top to bottom to paste the film to the window. 

  5. Dry with your hair dryer: Turn on your hair dryer and run it over the film, removing wrinkles and shrinking the excess edges so the film fits flush against all sides. 

Replace your windows’ caulking

A homeowner caulking a window

  • Best for: Any season

  • DIY difficulty: Low

  • Cost: $30-$40

Caulking is an easy, affordable way to close any gaps around your windows that allow air to pass through. It is a perfect home improvement for prepping for the winter months. Window gaps are notorious for causing your HVAC unit to work overtime to get your home up to temperature and compensate for the lost heat or air. By sealing the gaps, you won’t have any air that sneaks out, which causes your system to work harder and makes your home less energy efficient. 

Like window film, caulking is a simple process. Follow these steps below to caulk your windows like a pro and seal off any gaps:

  1. Prep the surface: Remove old caulk with the help of a razor or putty knife.

  2. Seal off other areas: Use painter’s tape to seal off the area above and below where you plan to caulk.  

  3. Apply caulk: Cut off the tip of your caulking tube before squeezing out a line of caulk along the area you need to seal.

  4. Smooth: Run a finishing tool down the line of the caulk to smooth it out and remove the excess caulk. 

Install weatherstripping

Weatherstripping being installed on a window by a homeowner

  • Best for: Winter

  • DIY difficulty: Low

  • Cost: $10-$50

Weatherstripping is another insulation process, like window film, that seals off gaps. The difference is that weather stripping is used in moveable areas, whereas caulk is not. Installing weather stripping is also quite easy and can be done in as little as three steps.

  1. Measure and cut: Measure out strips of your weather stripping that match the length of the area you need to seal before cutting with scissors. 

  2. Apply adhesive: Peel off the adhesive backing of the strips before pressing down on the cracks or gaps. 

  3. Repeat: Repeat the steps above over all windows. 

Use a draft snake

A draft snake in front of a window

  • Best for: Winter

  • DIY difficulty: Low

  • Cost: $12-$30

One of the most straightforward window insulation methods is a draft snake, also known as a draft stopper. These cost-effective sealants are incredibly easy to use, as they require pushing against the draft or crack. They are also removable, as you don’t paste them to a surface but slide them against one instead.

The only thing to remember is that draft stoppers only come with one in a pack and reach a certain length. Depending on the size of the crack, you might need more than one to seal the draft properly. 

Change your window treatments

A homeowner installing window treatments

  • Best For: Any season

  • DIY Difficulty: Low

  • Cost: $100-$800

Believe it or not, window treatments have a lot to do with the insulation of your windows, especially when they’re constructed with energy-efficient materials like thermal curtains. These treatments insulate your home by preventing air or heat from coming in through the glass when they’re drawn.

Upgrade to energy-efficient windows

A window installer installing energy-efficient windows

  • Best For: Any season

  • DIY Difficulty: Hire a professional

  • Cost: $750-$1,400 per window

Energy-efficient windows are different from standard ones in that their sole function is keeping the conditioned air inside your home. These windows are usually constructed with multiple panes to prevent air from passing through. Low-E glass is also used, which blocks UV light from entering your home.

This home improvement project will require the help of a window professional who knows how to remove your current windows and install these new ones properly. 

Install storm windows

Storm windows being installed by a professionalImage source: Energy.gov

  • Best For: Any season

  • DIY Difficulty: Hire a professional

  • Cost: $188–$342 per window

Also different from standard windows, storm windows are excellent for insulating your home and protecting your property from high winds during a storm. If you live somewhere where it is exceptionally stormy year-round or during a set season, you could benefit significantly from this home improvement project.

Like energy-efficient windows, storm windows provide an extra layer to your window area but are used along with your existing windows. Storm windows are usually placed in front of or behind your current windows and are made with Low-E glass. Adding these windows also requires the assistance of a window professional. 

Cost comparison: window insulation methods

With so many window insulation options available, you have to find the proper method for your home and the right one for your budget. Most window insulation methods are budget-friendly, as they are simple home improvement projects that can be completed in less than a day. However, once you decide to upgrade the type of windows you have, the cost increases significantly. 

Browse the chart below for a breakdown of cost estimates for each insulation method.

Method of Insulating


Insulation film

Kits cost less than $15 on Amazon, though this typically costs between $15 and $30


$30 to $40


$10 to $50 per roll of material

Draft snakes

$12 to $30

Window treatments

$100 to $800 per window

High-quality window replacement

$750 to $1,400 per window

Storm window installation

$188 to $342 per window

Benefits of window insulation

Window insulation provides your house with several benefits, including:

  • Energy savings: Window insulation controls temperatures, making your home energy efficient and boosting your utility bill savings.  

  • Better temperature control: Window insulation is about keeping your home's temperatures regulated and increasing energy efficiency. That means your air-conditioned air stays inside, and the temperature outside does not sink in through gaps or seals. 

  • Noise reduction: Because of the additional layer window insulation provides, noise is much harder to travel through and is almost blocked out. So, insulation can be an incredible benefit if you live in a noisy area.

  • Boosted property value: Because of the benefits window insulation provides, it’s a home improvement project that can significantly increase your home’s property value.

Window insulation: the bottom line

Insulating windows is an excellent idea if your home is struggling with energy efficiency or you’re looking to increase your energy savings. Sealing off gaps and cracks in your windows also helps increase the longevity of your HVAC system since it doesn’t have to work harder to reach your set temperature and make up for the lost air. 

Most of the insulation methods on our list can be implemented year-round to prepare your home for the hot and summer months, but it’s important to note whether or not your preferred method requires the help of a professional.

Frequently asked questions

If you’re in a pinch and need quick (also extremely budget-friendly) insulation until you find a more permanent solution, you can use bubble wrap for now. This method works similarly to the plastic film method since you’ll measure and cut a sheet of bubble wrap that fits around your window sill. Choosing the correct sheet is the key to using bubble wrap for window insulation. The larger the bubbles, the more air or heat they’ll trap and not allow to pass through drafty windows.

Vertical louvered blinds work best at keeping heat out of your home since they completely close and block out the summer heat. When shut, they also reduce the glare that can seep through other blinds that heat your home. Honeycomb shades (also known as cellular shades) are also effective at reducing air leaks during the summer since they’re built with honeycomb-shaped cells that trap air and reduce your home’s energy costs.

Yes, window insulation works by creating an airtight seal around your window to keep air or heat from escaping and letting the outside air in. This keeps your home more comfortable year-round by providing better temperature control on top of a decrease in energy bills since air is not leaking out.

Window film is highly effective at insulating your home in the winter. It helps to seal off gaps or cracks and acts as another layer that prevents heat from escaping or cold air from seeping in through the glass.

Written by

Ashlyn Needham Content Specialist

Ashlyn is a freelance writer with 8 years of experience writing interior design, DIY, and renovation content. Her work has appeared in multiple publications including The Spruce, Southern Living, House Beautiful, Fixr, and more.