Different Ways to Insulate Your Home Windows for the Summer

Why You Need to Insulate Windows for Summer

The days are getting longer, and the temperatures are creeping up. It will be time to turn on the AC before we know it.

Now is a great time to assess the efficiency of your windows in maintaining a comfortable indoor temperature. Drafty windows, thin glass, and insufficient window treatments make it easier for the stifling summer heat to find its way into your home, making your AC work that much harder and increasing your energy bill. In fact, the Department of Energy estimates that windows account for 25-30% of residential heating and cooling energy use.

You can insulate windows for summer in multiple ways. Some methods are more effective—and expensive than others. Let’s review the most common insulation options so you can pick the treatments that work for you.  

You can insulate windows for summer in multiple ways. Some methods are more effective—and expensive—than others. In this comprehensive guide, we'll review the most common insulation options so you can pick the treatments that work for you, helping you stay cool while reducing your energy costs.

 

How to Insulate Windows to Keep Heat Out

Here’s how to insulate windows to keep your home cool through the summer. These six solutions are roughly ordered from least expensive to most expensive. Bear in mind that the best window insulation for summer entails a combination of the options described below.

1. Use a draft snake.

If your windows have an imperfect seal, a draft snake or stop is a quick, inexpensive solution. A draft snake is just a few dollars, and it’s readily available online and in hardware and home goods stores. There’s no installation to speak of. Simply wedge the snake where the window sash meets the sill.

Draft snakes have their uses, but they can be a bit bulky to place on a window. They also do nothing to prevent drafts that might come from the top or sides of a window’s framing.

DIY Draft Snake Option: You can make your own draft snake by filling a tube sock with rice, dried beans, or even sand, and then sewing or tying the open end shut. This homemade solution costs next to nothing and works just as well as store-bought options.

2. Apply weather stripping.

Just like a draft snake, weather stripping can limit the exchange of air through a drafty window. Weather stripping is a little less conspicuous, though, and you can apply it to the entire perimeter of a window.

Weather stripping is inexpensive and easy to apply. Simply measure an appropriate length of stripping, peel back the covering to expose the adhesive, and apply firmly to your window framing. You can remove weather stripping whenever you like, so it’s a great way to insulate apartment windows.

Types of Weather Stripping for Windows:

• V-strip/tension seal: These plastic or metal strips spring open to seal the gap between the sash and the frame
• Felt: Inexpensive but less durable, felt strips work well for windows that aren't opened frequently
• Foam tape: Self-adhesive foam is easy to install and effective for sealing smaller gaps
• Rubber gaskets: More durable option for windows that are opened regularly
• Silicone caulk: For permanent sealing of non-moving parts of windows

3. Apply reflective window film.

Draft snakes and weather stripping won’t stop the hot summer sun from warming your home. If your windows get a lot of sun, you can apply a thin film to reflect sunlight. Some inexpensive film is made for any homeowner to install. Other kinds of higher-grade film must be installed by a professional.

Reflective film is good at keeping a home cool in the summer, but some homeowners don’t find it to be aesthetically pleasing. For this reason, reflective film is sometimes more common on office buildings and storefronts.

4. Hang blackout curtains.

Blackout curtains are made of thick fabric that is especially effective in blocking light and, by extension, heat. Think of the curtains you might see in a hotel room.

Blackout curtains tend to be heavy, so they might require stronger mounting brackets, but they are otherwise no harder to install than any other kind of curtain. Some people find blackout curtains to be a little too effective, however. They can completely darken a room in the middle of the day, which some people find disorienting. You might want to mitigate the heat from the summer sun, but not at the expense of losing all the natural light in your home.

5. Install cellular, honeycomb, or solar blinds.

Cellular, honeycomb, and solar blinds are elegant, attractive, and can trap or reflect the sun’s heat while still allowing some ambient light to pass through. They’re a wonderful way of keeping your home cool and comfortable, but quality blinds can be expensive. The costs add up when you consider professional installation.

6. Replace your windows.

Finally, you can make your home more energy efficient by replacing your windows entirely. Thermal, double-paned, or heat-proof windows are more than twice as effective as standard glass when it comes to keeping your home cool in the summer and warm in the winter. Most models use two panes of glass with insulating argon gas sealed between them.

The downside is that replacing your windows is quite expensive. The argon between the panes escapes slowly over time, too, so you may need to replace these windows again in about 20 years.

Additional Ways to Insulate Windows for Summer

Beyond the six methods mentioned above, here are some additional techniques to consider for summer window insulation:

7. Install exterior window shades or awnings.

Exterior solutions prevent heat from reaching the glass in the first place, making them more effective than interior options. Awnings can reduce solar heat gain by up to 65% on south-facing windows and 77% on west-facing windows.

Types of Exterior Window Coverings:

• Fixed awnings: Permanent structures that provide consistent shade
• Retractable awnings: Can be opened or closed as needed
• Exterior roller shades: Mount outside the window and can be raised or lowered
• Bahama shutters: Hinged at the top and prop open at an angle
• Solar screens: Fine mesh screens that block UV rays while maintaining visibility

8. Plant shade trees or install trellises.

Natural shade is an eco-friendly way to keep your windows cool. Deciduous trees are ideal because they provide shade in summer but allow sunlight through in winter when they lose their leaves.

9. Apply caulk to seal cracks and gaps.

Before adding any window treatments, make sure your windows are properly sealed. Caulking is an inexpensive way to seal small cracks around window frames.

How to Apply Caulk Effectively:

1. Remove old caulk and clean the area thoroughly
2. Cut the caulk tube nozzle at a 45-degree angle
3. Apply a continuous bead of caulk to all joints and seams
4. Smooth the caulk with a wet finger or caulk smoothing tool
5. Allow to dry completely before painting (if necessary)

10. Use bubble wrap for a quick, temporary solution.

For rarely-used windows or temporary insulation, bubble wrap provides surprisingly effective insulation. This method is especially useful for basement or utility room windows.

11. Install window inserts or interior storm windows.

Window inserts are custom-built acrylic or glass panels that create an additional insulating air space inside your existing windows. They're less expensive than replacement windows but offer significant energy savings.

Benefits of Window Inserts:

• Install without any permanent modifications to your home
• Can be removed seasonally if desired
• Reduce noise transmission
• Improve insulation without changing the exterior appearance
• Typical cost: $100-$300 per window (much less than replacement)

Evaluating Which Window Insulation Method Is Right for Your Home

When deciding how to insulate your windows for summer, consider these factors:

Cost Considerations

 

Effectiveness Comparison

 

Rental-Friendly Options

If you're renting and need non-permanent solutions:

• Draft snakes
• Weather stripping (removable types)
• Tension rod curtains
• Removable window film
• Portable window inserts
• Free-standing outdoor umbrellas

Combining Methods for Maximum Effectiveness

For the best results, consider combining multiple insulation methods:

1. Seal air leaks with weather stripping and caulk
2. Apply reflective window film to reduce solar heat gain
3. Add interior window treatments like cellular shades
4. Use blackout curtains during peak heat hours
5. Consider outdoor shading for south and west-facing windows

Seasonal Window Insulation Strategy

Different seasons require different approaches to window insulation. Here's a year-round strategy:

Summer Window Insulation (May-September)

• Keep window coverings closed during the day, especially on sun-facing sides
• Open windows and coverings in the evening when outside temperatures drop
• Use reflective treatments to block solar heat
• Install exterior shading where possible

Fall/Spring Transition Periods

• Use adjustable window treatments to allow solar heat gain on cool days
• Keep windows insulated on hot days
• Remove and store seasonal treatments as needed
• Check and repair weather stripping and caulking

Winter Window Insulation (November-March)

• Allow sunlight in during the day to warm the home
• Close insulating treatments at night to retain heat
• Add plastic film insulation for additional protection
• Use draft stoppers to prevent cold air infiltration

Measuring the Effectiveness of Your Window Insulation

After implementing window insulation methods, monitor their effectiveness:

Simple Testing Methods

• Temperature test: Use a thermometer to measure the temperature near insulated vs. non-insulated windows
• Candle test: Hold a lit candle near window edges (when not drafty outside) to detect air leaks
• Thermal imaging: Use a smartphone thermal camera attachment to identify heat loss areas
• Energy bill comparison: Track cooling costs before and after installation

Signs Your Window Insulation Is Working

• Consistent indoor temperatures
• Reduced need for air conditioning
• Less noticeable temperature difference near windows
• Decreased energy bills during peak cooling seasons  
   

 

Creating a Cooler, More Efficient Home

Properly insulating your windows for summer is one of the most effective ways to improve your home's energy efficiency and comfort during hot weather. By implementing some of the strategies outlined in this guide—whether simple DIY solutions like weather stripping and window film or more substantial investments like high-efficiency window replacements—you can significantly reduce your cooling costs while creating a more comfortable living environment.

For comprehensive protection of your home's cooling system during the hot summer months, consider supplementing your window insulation efforts with a home warranty from Liberty Home Guard. Our plans provide peace of mind and financial protection against unexpected AC breakdowns when you need cooling the most.