How to insulate windows – 4 easy ways to keep your home warmer

Find out how to insulate windows and improve the comfort of your rooms, with these simple methods

a man insulating windows in the middle of a house-build or renovation
(Image credit: Getty Images: Dana Neely Creative #: sb10068543b-001)

Feeling the cold inside your home and wondering how to insulate windows to keep your property warmer? Well, the good news is that you don’t have to splash out on new windows to make your environment more comfortable.

You can insulate windows in winter to make your home cozy, much like you would insulate an attic, without spending the earth. What's more, it’s a quick and simple DIY job. Solutions like plastic film and bubble wrap are easy to fit, and can make a whole lot of difference to the atmosphere of your home.

We’ve put together the top ways to insulate windows, together with expert advice on getting the job done right.

How to insulate windows – four methods

If your home has drafty windows or they’re not the modern energy-efficient windows you’d prefer, there are fixes that can be achieved quickly and simply, so the dilemma of how to insulate windows is an easy one to solve.

Old or damaged panes or windowsills instead? You’ll need to know how to install a window.

1. Opt for window film

The number one choice when you’re deciding how to insulate windows, whether you're planning garage insulation or insulation in a shed, is window film. Made from plastic, window film is easy to apply and comes in a kit which generally includes the film, and tape for the window. 

Before you start, clean the window itself, as well as the frame.

To use film to insulate your windows, you’ll need to measure each of the windows you want to apply it to, then cut the film to size with an allowance on either side following the manufacturer’s instructions. Then all you’ll need to do is apply the tape around the window frame and stick the film to it, positioning it so there aren’t any wrinkles. Finally, use a blow dryer to heat-shrink it for a smooth finish.

You can remove the film from your windows when the season changes, but do bear in mind the tape can lift paint from the frame when you take it off if it wasn’t in the best condition beforehand.

2. Use bubble wrap to insulate windows

Bubble wrap is a good way to insulate a window if a warmer home is the urgent requirement. We have to admit that it’s not going to help any with the view, though.

To apply, you need to mist the clean panes of glass with water and then place the bubble side of the wrap against the damp window. You can use tape to hold the bubble wrap in place but, like the adhesive tape in a window film kit, it can lift paint when you come to remove it in spring.

Again, this isn't the most practical solution, but it is speedy and effective if you're wondering how to insulate windows fast.

3. Use caulk

To insulate windows effectively, you may need to use a combination of methods for the best results. So, if you can feel a draft coming through the window, before you apply plastic film, try using caulk to seal the gaps.

Caulk is easy to apply and can be used around all the joints in the window frame and the joint between the frame and the wall. 

‘Use a knife to scrape any old caulk or peeling paint off exterior or interior window edges,’ advises home improvement expert Arnold Long, general ops manager at Mr. Blue Plumbing (opens in new tab). ‘Then, fill a caulking gun with silicone caulking.’ 

Got a gap where the window moves? Use weatherstripping instead, either fitting it where there is none or replacing old weatherstripping. 

‘When weatherstripping begins to crumble, replacing it will be one of the quickest ways to improve your home’s insulation without having to replace the entire window,’ says Keith Gutterman, VP of marketing and business development at Storm Tight Windows, part of Leaf Home Enhancements (opens in new tab)

‘Adhesive-backed stripping can be easily removed by hand without any equipment. Once the weatherstripping is removed, we recommend cleaning the window sash with a damp rag and household cleaner. Allow it to dry thoroughly before applying new weatherstripping.’

4. Hang insulating curtains

Hanging insulating curtains at the window can also help with insulation. This can be a solution you use after caulking and/or weatherstripping, and combined with the use of window film or bubble wrap.

One of our favorite window dressing ideas for chilly homes, insulating curtains are made with a thermal lining. In other words, the insulating part isn’t what you see so they’re as stylish in appearance as other window treatments. 

Owner and chief operating officer of Colony Roofers (opens in new tab) Zach Reece recommends using curtains to insulate windows. ‘The simplest and most design-friendly way to insulate your windows is to buy thermal curtains,’ he says. ‘Not only do they add a touch of class to your room, but they are incredibly effective at blocking outside light and very effective at preventing cold air from entering your home.’

Pay attention to the size of the curtains. They should be floor length, and of sufficient width, too. ‘Make sure that the curtain rods are positioned so the curtains cover window frames fully,’ says Karen Condor, home energy expert with US Insurance Agents (opens in new tab)

How can I insulate windows cheaply?

It’s very easy to insulate all types of windows cheaply. Whether you use plastic in the form of window film, or bubble wrap, you can insulate windows in winter for a very low outlay plus just a little of your time.

You might also need to caulk any gaps, plus add weatherstripping to the windows, but, again, these are low budget solutions and speedy ways to fix drafty windows.

Curtains with a thermal lining can be found at low cost. However, you may want to have custom drapes with a thermal lining made for you window – in which case, the price will rise according to the curtain fabric selected and the labor involved in making curtains of the right size for the window.

How do I insulate my windows for winter?

When heating season arrives there are two main ways to help your home stay warmer. To insulate windows in winter, you can put a stop to cold drafts and keep the warm air in your home with heat-shrink window film. 

If you don’t mind obscuring the view somewhat, bubble wrap, as mentioned, is an alternative that can keep a room cozier. And it will still let the light through. The bubble wrap boosts a single glazed window’s resistance to heat flow – its R-value – cutting the heat loss.

Check your windows for gaps, too, and fill any, and hang curtains with a thermal lining as well.

Sarah Warwick
Freelance Editor

Sarah is a freelance journalist and editor writing for websites, national newspapers, and magazines. She’s spent most of her journalistic career specialising in homes – long enough to see fridges become smart, decorating fashions embrace both minimalism and maximalism, and interiors that blur the indoor/outdoor link become a must-have. She loves testing the latest home appliances, revealing the trends in furnishings and fittings for every room, and investigating the benefits, costs and practicalities of home improvement. It's no big surprise that she likes to put what she writes about into practice, and is a serial house revamper. For, Sarah reviews coffee machines and vacuum cleaners, taking them through their paces at home to give us an honest, real life review and comparison of every model.