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 1458 Reviews logo

cynthia g

Great product, well made. Helpful staff and great communication



The window fits perfectly and was easy enough to install by myself. It unfortunately does not reduce much noise, if any at all, from outside, that might be something for the more premium versions. I have noticed that it does help keep in warmth however which is nice.


Laura K

They are wonderful and are keeping out the cold air this fall!


Travis P

I love my Indow inserts! The installation was very simple and the Indow team helped me the entire way. I live near a busy road, an interstate, and an airport. Although not unbearable the noise from those aforementioned sources was noticeable (key word "was" :) ). I am so glad I found Indow because their inserts were affordable, not permanent, and easy to install. The Indow inserts significantly reduced the noise! I don't have official measurements but I'd say the inserts cut down at least 50% of the noise which is a huge improvement!


Imogene S

I am a 78-year-old woman and the windows in question are above two sliding glass doors. All 4 are almost 3'x4' in size. I had absolutely no problem ordering and installing them myself. The Indow rep I worked with initially answered all my questions. Indow helped all the way with the measurements, delivered the indows early, and provided detailed instructions on their installation. My only advice to potential customers is to measure thrice and order once. The key to successful inserts is a perfect fit - with the Indow-supplied laser, you can do it!


Tony H

Great quality & service. Inserts are a good fit. Will be able to give better feedback after we have been hit by severe winter weather.


Rex R

Great product, fit and finish was high quality. The difference of road noise was amazing. I rarel. Hear vehicles any more. Before it sounded like they were going to drive theough the wondow. Great invention!


Sally B

The inserts weren’t too difficult to place and have made a huge difference in reducing outside highway noise. Love that they are barely noticeable once in place so don’t detract from the window view or appearance at all.



Wow! A company that is honest and transparent about their terrific product. Thank you! Received my window inserts this morning. They work well cutting road noise dramatically. Easy to install. But most of all doing business with them has been an uplifting pleasure. Warms my heart to see honest,dedicated people making the world a more peaceful place!


Carol K

From start to finish, working with Indows has been a great experience. They made sure that the measurements I took were accurate so that the finished product fit perfectly. The Indows, definitely reduce the sound out on the street. In a small guest room inn our Inn in San Francisco, the need to open the window and air out rooms is a necessity so we will see how suitable the inserts are in the long run.


Mary B

I am very grateful to have found and purchased Indow dor several problematic windows in my 1909 house. Wanting to retain the stained and other leaded design windows but making them more weather efficient, Indows solved the problem. I just popped them in and viola! Service was also terrific. I do have to adjust the seal occasionally on one of the picture windows but it is no problem.


Miriam L

Our 9-pane living room window was letting cold air in, so we purchases 9 Indow Window panels. They were fairly easy to install and have held up for a few years now. They make a huge difference in comfort in the living room. Great idea you had there!


Sam P

The ordering process was smooth and easy. Window arrive we'll packed and clean. Installation was easy but the safety chains make no sense.


Tamara S

I work five nights a week and keep night hours on my days off, so having a pitch-black room is essential to my health and happiness. After reading some reviews I settled on the Indow sleep panels. My house was built in 1901. I have two bedroom windows that are about 6' tall and 3' wide. From the time I got in touch with Indow, through the measuring process, through the production and delivery of my inserts I felt like they were supportive. Reading the installation guide before their arrival was essential in preparing me for the process. I knew I'd need to install window brackets with a power drill and that unboxing the inserts might be a bit of a chore. This made the installation process smooth which I greatly appreciated. The inserts arrived a few hours after I'd worked through the night, so I was ready to get them installed in short order and get to sleep at a reasonable hour that day. As to their efficacy, the panels block all the light. The sound dampening isn't powerful, but I knew that going in as well. The inserts need to sit 4" from the glass for the full dampening effect and mine can only sit at about 2". There is a dampening effect, just not at the 50% noise reduction that they're capable of. The delivery service that shipped to my house didn't call to schedule the delivery as the instructions said they would. That's the only thing that didn't go according to plan, but I was home so it worked out. Other than that one thing, the panels perform as I hoped they would. I'm grateful for my dark room and my consistent deep sleep because of them. I would work with Indow again in the future.


Gregory B

We love our new inserts. All nine fit perfectly in our varied windows and now we can enjoy a warmer and quieter winter. Indow was fantastic to work with through the entire process. Thank you, Indow!