How to Winterize Windows With Window Insulation Kits & More

Stay warm & save money

Keeping your office warm in the winter is about more than just buying heaters and blankets. You can help your coworkers and customers stay warm by winterizing your windows. Wondering how? This guide will show the way.

How to insulate windows for winter

Winterizing your windows means sealing up any gaps or cracks that might let the heat out and the cold in. Window insulation kits, caulk and draft stoppers can have a big impact with a small investment. 

The first step to insulating your windows is measuring them. Collect measurements for the length of your window sill, the length and height of your window frame and the length and height of your window sashes (also known as the parts of your window that move). Clean any surfaces you plan to insulate with a damp cloth and then allow them to dry. That will help your solutions seal and adhere.

Window insulation kit

A window insulation kit is one of the most popular ways to winterize because it’s effective and easy to use. Each kit typically contains two things: sheets of window insulation film and a roll of double-sided tape. You’ll need one sheet of window insulation film for each of your windows, so double check how many sheets are included in each kit, and maybe get a few extra in case you make any mistakes during installation. You’ll also need a hair dryer or heat gun.

Follow these steps to install your window insulation kit:

1. Close and lock the window to seal it as tightly as possible.

2. Measure out and cut strips of double-sided tape for the top, bottom and sides of your window.

3. Take a strip for the side of the window, remove the cover on one side to reveal the sticky surface and then apply it to the side of the window frame, paying special attention to keep the tape as smooth and straight as possible. Work from the top down.

4. Repeat for the bottom, top and other side of your window, and then peel the covers off the tape strips.

5. Unfurl your first piece of plastic and orient it with the window. Line its top left corner up with the top left corner of your tape and stick it. Line the bottom left corners up and stick them. Stretch the plastic across and stick it to the top right and then bottom right corners.

6. Once you’re satisfied with the alignment of the plastic, push it into the tape on all sides to seal it.

7. Turn your hair dryer to low and start waving it over the plastic from six to eight inches away. Use wide, sweeping arcs and work your way across the plastic. You should see it tighten over time. Continue until it’s taut all across its surface.

8. Trim off any excess plastic.

Draft stopper

If you aren’t happy with the look of a window insulation kit or are looking for a more temporary solution, consider a draft stopper. A draft stopper, or draft snake, is typically a cotton sleeve filled with cotton, sand or foam. Traditional stoppers compress into the gaps on the inside of your window, creating an effective, adjustable seal. 

The heavier the stopper, the better a seal it will create. Some more modern draft stoppers are double-sided, running under the window to seal from both sides.

Thermal curtains

Thermal curtains are often the most visually appealing window covers for winter. They’re made with multiple layers of thick, heavy fabrics that help to insulate the room. They also tend to run all the way to the floor to improve heat retention. You can hang them anywhere regular curtains already hang, and you’ll find them in a variety of attractive styles.

Because they use such heavy fabrics, thermal curtains often double as blackout curtains, so if you’re hoping to let sunlight in while keeping the cold out, they may not be the best option. They also don’t insulate as well as a window insulation kit, weatherstripping or caulking likely would.

Weatherstripping

If you’re looking for an all-but-invisible window winterizer, weatherstripping may be the solution for you. When installed correctly, it hides inside your window’s facade while improving its seal. It’s also relatively easy to install.

V-channel weatherstripping, which may be the most common kind, is made of vinyl. If you have double-hung windows, you’ll need to cut your weatherstripping into the following pieces for a full seal:

• Two strips as long as the sides of your inner sash

• Two strips as long as the sides of your outer sash

• Three strips as long as the bottom of your inner sash

Now you can follow these steps to install:

1. Open the inner sash as high as it can go.

2. Grab the strips you cut for your inner sash. Peel the backing off of one strip while leaving a little at the top of the strip.

3. Press the strip along the inside of the window frame from top to bottom, ensuring the V of the strip points in at you.

4. Once the strip runs the height of the sash, fold the V over and push the top of the strip up through the space between the sash and the window frame.

5. Repeat steps 1–5 on the other side of the sash.

6. Close the sash to expose the bit of weatherstripping at the top that still has backing. Peel the backing off and press it into place.

7. Open the top sash as low as it can go and repeat these steps.

8. Open the inner sash again and apply weatherstripping to the bottom, where the sash meets the frame. Remember to keep the V pointing in at you.

9. Partially close the inner sash and open the outer sash so that it pokes out from below the inner sash. Apply your weatherstripping in the same way as in step 8.

10. Apply weatherstripping to the inside face of the outer sash with the V facing down.

Caulking

If your window has gaps in stationary elements, you can use caulk to seal it for the winter. Acrylic latex and silicone caulk are good options for creating a tight seal and preventing air escape.

Start by using a lit candle or stick of incense to find where cold air is getting in. If the flame or smoke suddenly gets blown around, you’ve found a gap that needs sealing. After clearing away old caulking with a putty knife, cleaning with a damp towel and allowing the window to dry, you can apply fresh caulk.

When using a caulk gun, hold the trigger with your dominant hand and place your other hand on the barrel for support. Keep your wrists straight and move only your body and elbows to maintain an even angle. Start at one end of the gap and stop in the middle, then repeat from the other end. Once you’ve laid down enough caulk, you can use a caulk applicator or wet fingers to smooth it out. Clear away any extra caulk from the window and clean the tip of your caulk gun.

Winterize for less with Walmart Business

Insulating your windows is a great way to be energy efficient and save money. You can save even more by shopping with Walmart Business. With a free account, you can shop a wide range of heating solutions and have orders over $35 shipped straight to your door for free.¹ Upgrade to Walmart Business+ and you can even have orders over $35 delivered from a nearby store.² All told, Walmart Business+ could save you over $500/year.³ Start your membership today.

¹ Excludes most Marketplace items, freight and certain location surcharges.

² Restrictions apply.

³ Savings based on 1 free $35+ delivery order vs. $9.95 fee and 1 free shipping order under $35 vs. $6.99 fee biweekly, plus 2% Walmart Business Rewards on monthly order >$250 (average value of $400).