Insulate Old Windows Without Replacing

A close-up image of a person installing window inserts. They are wearing a black dress and have a clear bracelet on their left wrist.

Have you noticed a draft coming in from your windows during the colder months of the year? If you have old, out-dated windows, they could be responsible for a significant amount of heat loss and air leakage in a home.

In addition, windows with cracked glass, broken seals, and poor insulation cut into the energy efficiency of the home, by overworking the HVAC system and driving up energy bills.

So, if your home is already having trouble maintaining a comfortable temperature for more than a few minutes, and it seems impossible to keep the house warm, it may be time to consider new insulation options for the windows.

6 Ways to Insulate Windows without Replacing Them

1. Install Window Inserts

Tall, vertical window framed with old, red brick and white paneling, with a window insert inside the frame.

Window inserts offer excellent insulation during those frigid winter months while being cost-effective compared to full window replacements.

Window inserts fit over the existing interior window. Some, like the ones from Indow, are held in place using compression tubing, creating a tight seal around the window frame without damaging the window or the frame. Indow inserts are made with acrylic, which has much higher insulation properties than glass. So, even if installed in front of windows with small cracks or poorly sealed windows, the inserts will eliminate drafts and improve the overall energy efficiency of the home.

The inserts are low-profile and are virtually unnoticeable when installed. A great option for historic homes, the inserts are custom measured to fit perfectly and won't damage the historic nature of the home, letting you preserve their beauty.

Inserts not only reduce drafts and help maintain a comfortable temperature within the home, but there are also options that can offer significant soundproofing capabilities or provide light blocking and UV protection. These are beneficial to have all year round, as window inserts also provide great insulation in the warmer months.

2. Bubble Wrap

If the need for a warmer home is urgent, covering the windows with bubble wrap is an option. Bubble wrap is not the most aesthetically pleasing or permanent solution, but it is cheap and easy to do in a pinch.

For the best results, choose a wrap with larger bubbles instead of the smaller bubbles, and cut the wrap so it covers the window and overlaps the seams. Mist the glass panes with water and apply the bubble side to the damp windows. The bubble wrap can be taped into place, but there is a risk that the tape will peel the paint off the walls if left for too long. For even better insulation, double up the layers of bubble wrap.

This will block the window's view, but light will still pass through the bubble wrap to brighten your space.

3. Traditional Caulk

If you feel a draft coming in through the windows, they may need some fresh caulk. Caulk is easy to apply and can be used to seal gaps between the window, the frame, and the wall.

Before applying, it is best to scrape off any old caulk and peeling paint in order to achieve a proper seal that will last.

4. Insulated Glass Units

Two sheets of glass are leaning against a wall, an example of an insulated glass unit.


If your window frame is still in good condition, you could just replace the glass with insulated glass units. Insulated glass units are made up of two sheets of glass separated by an inert gas. This separation diffuses heat transfer in and out of your home, in order to provide more insulation.

Sometimes referred to as double-pane glass, insulated glass units are a sealed system, so if one of the sheets of glass cracks or breaks, the entire unit must be replaced. The unit can be customized depending on how much insulation is needed.

You can choose thicker or thinner pieces of glass (the thicker the glass, the better the insulation), the width of the spacer (the piece that separates the glass where they meet at the edge of the window frame), and the type of gas that is used between the panes (commonly used gases include argon, krypton, or a mixture of the two). Depending on the customization, however, these units can get costly fast.

5. Thermal Curtains

One of the more design-friendly insulation options is to put up thermal curtains. These aesthetically pleasing window coverings have a special thermal lining that holds in warm air during the winter and blocks out the heat during the summer for year-round use.

Thermal curtains work best if they are floor length and wide enough to sufficiently cover the window. For further insulation, Velcro tape can be added to the curtains and wall for a full seal.

These curtains can be used year after year and opened during the warmer days. In addition to their insulating capabilities, thermal curtains also block out light and act as noise dampeners. However, you'll have to decide if you want insulation benefits or sunlight and a view, as you cannot have both with these curtains.

6. Draft Stoppers

A draft stopper is a snake-like, cloth tube filled with materials like sand, beans, rice, or batting. They are typically laid across cracks in doors and windows to act as a fabric weatherstripping by preventing cold air from leaking in and warm air from escaping out.

Draft stoppers can be found at home goods and home improvement stores, but it is also an easy and fun DIY project for the crafty crowd. Simply choose the preferred fabric, cut and sew it into tubes long enough to cover the width of the windowsill and fill it.

Draft stoppers do not block the window or prevent it from opening when necessary. However, they can only cover the bottom of the window and cannot cover the top or the sides. Therefore, they may not be able to provide complete insulation if there are cracks throughout the seal.

How Indow Can Help

A person is installing a window insert into their window. They are wearing a purple sweater, hoop earrings and brown glasses.

Indow offers a range of window inserts that fit the needs of every home. With our inserts, homeowners don't have to spend replacement window levels of money to get effective insulation.

Indow window inserts allow you to enjoy the comforts of your home all year round. Our easy-to-install solutions not only make your home more efficient and safe, but our custom options ensure you get the best fit for your home.

Reach out today for a free estimate.

Customer Reviews


4.49 Average 1493 Reviews logo


Brian was very helpful & informative. He helped me order the correct windows for my needs. They were shipped with the utmost of care & arrived ahead of schedule. Ultimately, the Indow Windows have been very helpful in muffling unwanted noises & they have helped save on our energy costs. Thank you, Indow Window!

Posted 1 week ago

Cynthia M

Very happy with the reduction in noise. Easy to install and use. Great customer service.

Posted 1 month ago

Juli E

We are thrilled with our Indow window inserts! I'd been on the lookout for a more permanent solution to leaky windows in our third floor living space. I discovered Indow on social media but since then have learned of friends who'd had Indow recommended to them by their rennovation contractor. The entire process went smoothly with friendly reps at hand to talk through questions during measuring, etc. They fit perfectly and help us to maintain the beautiful design of the windows on our 100 year old home! Highly recommend!!

Posted 2 months ago

Jen F

Worth the money!

Posted 2 months ago

Elizabeth H

For townhouse living, this solved my problem with noise from my neighbor's with my kitchen window. A considerable decrease of noise indeed! Measurements were a bit frustrating so I recommend using a laser measurement device and following directions to use a string for the diagonal. They look great and were easy to push into place. I highly recommend as an alternative to buying a new window.

Posted 3 months ago


Easy to install, and instantly stopped drafts and dampened outside noises very effectively!

Posted 3 months ago

Robert C

The process could've been smoother with the sending of the measuring kit. There was a delay with weather in Oregon but then it felt like my kit was still delayed due to other reasons. Most new homes (like mine) have textured paint and it can also be inside your window frames. I measured everything out but I still have little tiny gaps due to the texturing. Not indows problem but just be aware you made need to sand or fill in those gaps yourself to get a perfect seal. I did the acoustic grade inserts and they have reduced some noise but they will not completely block or significantly reduce road noise. This is most apparent with deep or lower frequencies like truck exhausts or modified street racing cars that are quite popular these days. Taking the inserts out to open your windows isn't an easy task. The little metal hook they provide needs to be either bigger or you can attach something to it as a way to leverage yourself. Overall the process was average. I think they're definitely a good option for weatherproofing and some sound reduction depending on the type of windows you have. I would purchase again.

Posted 3 months ago

Shelley C

The process for ordering and installing the Indow Widnow inserts was so easy. They sent the measuring information and it had great instructions. The inserts were delivered by UPS was crushed on one corner, but the company had packed them well, so there was no damage. We installed them the same day. It works best if you have two people completing the installation. We felt the results immediately and are glad we spent the money to make our home just a little more efficient.

Posted 3 months ago

Barry B

The insert fits like a glove and insulates the window! No more frost and condensation on the interior of the window! Thank you for an easy, effective and attractive fix!

Posted 3 months ago

Susan A

The support during the entire process was wonderful, thank you so much for the extra quiet space!

Posted 3 months ago

Volodymyr R

Very good good quality. Overall very satisfied with this product and service. Thanks

Posted 3 months ago

Jane H

Our home was built in 1913 and has beautiful old wavy glass single-paned windows. I’m so glad we were told about Indows and didn’t have to replace the original windows. We live in Canada but had no difficulty placing the order and were very impressed by how accurately the company met its deadlines, including cross border delivery. The Indows inserts blend in perfectly with our home and the existing window frames. You don’t see them unless you’re actually looking for them. But what we did notice was how much warmer the rooms feel the minute the inserts were installed! I can’t speak to any heating bill savings because they just went in this week, but our home feels much, much cozier. Our contractor who took all the measurements and installed the Indows says: “Excellent instructional videos: clear and informative. Very impressed with the design and the product. Overall, the ease of installation is quite impressive. Working with all the staff at the company was great – everyone was very helpful.” I’m already recommending this company to any of my friends who live in drafty older homes and want to reduce their heating/cooling bills and do some good for the environment.

Posted 3 months ago


Don't be afraid of buying an older home with single pane windows. This company has you covered. Their inserts are super high quality and fit well thanks to the laser measuring kit they send. Highly recommended!

Posted 3 months ago

Katie M

We purchased three Indows to reduce drafts and noise in our bedroom, which faces the street. The improvement was immediate. Our house was built in 1958 and although we have exterior storm windows we didn't want to replace the windows outright due to cost and architectural consistency. These were an excellent solution.

Posted 3 months ago

Matthew L

Indow inserts were easy to measure, order and install. They've provided great insulation for old single-pane and stained glass windows in an antique home. We can significantly feel how much better the home holds heat.

Posted 4 months ago