How to Insulate Windows: 6 Great Ways

By: Josh Peterson, Planet Green  | 
A man installing plastic window film on a window. 
Installing window film adds another level of installation to windows, decreasing your heating and cooling costs. Potashev Aleksandr / Shutterstock

They add personality to the outside and inside of every home, but if they aren't properly insulated, windows can be a real strain on your finances. Fortunately, you can learn how to insulate windows easily and affordably.

You don't necessarily have to replace your existing ones with energy efficient windows either. You can enhance the energy efficiency of your home on a modest budget, and with products that are widely available at most home improvement stores.


Before we bring you up to speed on the available products though, it's important to understand how windows impact your home's heat.

Why Energy Efficient Windows are Important

Nobody is going to tell you to eliminate the windows from your home. Having said that, it would be much better on your energy costs. The window frame is ground zero for heat loss in the winter and heat solar heat in the summer.

The heat that's gained and lost via the windows in your home are can be responsible for as much as 30 per cent of the energy your home consumes on any given day [source: U.S. Department of Energy]. Which is why they get so much attention in these sorts of discussions. It's also why there's an entire industry built on making windows more energy efficient.


Below, you'll find a list of affordable and available ways to better insulate windows.

1. Blackout Curtains

As far as affordability is concerned, few of the items on today's list are as economical as blackout curtains. Assuming you already have a curtain rod, getting them for under $100 is very realistic. And that's before we even talk about energy savings.

Yes, blackout curtains can enhance the energy efficiency of your windows. They do this by trapping heat in the winter, and by preventing the sun's heat from penetrating your home.


In fact, these affordable and accessible window treatments can reduce the amount of thermal energy that escapes your home by as much as 25 percent [source: Innuwindow].

2. Cellular Shades

Cellular shades work a lot like blackout curtains, albeit they do a much better job of things. These innovative window shades rely on a unique, honeycomb design to not only block out light, but also help improve poor window insulation.

Unlike blinds, cellular shades don't have slats. As such, they aren't ideal for those who prefer a lot of natural light. Still, cellular shades can be a valuable year-round ally in your valiant attempt to stabilize indoor temperatures in the most energy efficient way possible [source:].


3. Weatherstripping

Adding weatherstripping is a go-to solution for insulating windows. And for good reason. Shoring up leaky windows will saves money, and few products do that more effectively than weatherstripping.

As a term, weatherstripping is a bit of a catch-all used to describe a variety of window insulation products. From door sweeps to tension seal to foam, there are a wide variety of options available and which one you choose depends on the job [source: U.S. Department of Energy].


4. Window Film

Window films, or energy films, are another inexpensive way to decrease heating and cooling costs. You don't have to sacrifice precious natural light, and most people can install it themselves.

They use a specially formulated plastic film to block harmful UV rays and enhance the insulation capacity all sorts of window surfaces [source: 3M]. Combine them with cellular blinds and proper weatherstripping, and sit back as your energy bills fall off a cliff.


5. Thermal Curtains

Thermal curtains are like blackout curtains on steroids. Not only do they block out all light when properly drawn, but they're also designed to restrict the flow in and out of your home [source: Bob Vila]. They help homeowners reduce energy costs, thanks in large part to their multi-layer design.

While all thermal curtains are constructed differently, most of them use multiple layers of foam and fabric to create a barrier between your home and the outside, all year long. You can count on them to restrict the flow of warm air in the winter and the cold air in the summer.


6. Bubble Wrap

Yes, bubble wrap. If you don't have the cash to finance a large window insulation, head to your local moving supply store and invest in a roll of bubble wrap [source: How to Go Solar].

The air bubbles along the surface of the wrapping material act as a barrier that has been shown to boost the insulation value of whatever window it's installed on. If you have the choice, opt for wrap with large bubbles to maximize it's effectiveness.