How To Insulate Glass Windows [Including Leaded Glass]

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Windows can be the reason your home is colder or warmer than it should be. If you have yet to insulate your glass windows and are wondering how it is possible, we have the answers for you. We've consulted the experts, and here's what they have to say.

To insulate the windows to either keep your home warm during winter or to keep the summer heat out, install one or more of the following:

  • Bubble wrap
  • Rubber weather sealing
  • Insulating shutters
  • Insulation window film
  • Cellular shades
  • Draft snakes
  • Black-out curtains

Keep reading as you learn the different methods of window insulation. We'll also discuss if is possible to insulate leaded glass and how to transform your windows into thermal insulated windows. 

Window Weather Seal Application, How To Insulate Glass Windows [Including Leaded Glass]

How Do  You Insulate Your Glass Windows?

Sliding glass door and his ventilation system

There are several ways of insulating your existing windows. The methods range from simple to complex, cheap to expensive, and basic to sophisticated technology.

Before you settle for a particular method, you need to assess the situation to identify the most critical areas in your windows that are letting in the air.

Windows will have different issues, for example, there could be gaps around the windows, or the windows do not close perfectly.

Insulation is important because it prevents loss of heat during winter, and keeps the heat out during summer. The methods to insulate your windows include:

Bubble Wrap

Click here to see this bubble wrap on Amazon.

Bubble wrap is a plastic wrapping composed of air bubbles. It is used to package items to prevent them from breaking but can also be used to insulate windows.

It is affordable and quite easy to install. All you have to do is spray the window with some water and stick the bubble wrap to it.

Once installed, the bubble wrap acts like another glass pane with a slightly distorted view. You shouldn’t mind the view if your main goal is to insulate your window. Bubble wraps have small or big bubbles. 

Rubber Weather Sealing

Have a look at this weather stripping on Amazon.

Weather stripping is especially good for older homes that are highly likely to have spaces around the windows. There are many types available—you only need to choose the one that fits your insulation needs and your budget. 

To install you need to remove the old weather stripping, measure the length you need of the new weather stripping, peel the back, and stick the adhesive side of the strip to the part you are insulating. 

Insulating Shutters

Bedroom window with a garden view in a luxury country house bedroom

Plantation shutters are not only excellent for insulating your windows but add elegant décor to your home. They offer a barrier between the interior of your home and the windows, keeping the heat out and preventing loss of heat to increase the warmth of a room.

Plantation shutters have an R-value between 3 and 6, meaning they are suitable for insulating your home. Wooden shutters have an R-value that is between 3 and 4, as they have tiny air spaces inside them, making the transfer of heat difficult.

Polyvinyl with aluminum core shutters has a slightly higher insulation R-value close to those made out of wood. It can be a better option as it is cheaper and lighter than wood.

Other non-wood shutters are composite or hollow shutters, which do not last very long when exposed to the climate. They are susceptible to warping and fading much faster than wood or polyvinyl.

Insulation Window Film

Check  out this window film on Amazon.

Window insulation film is a thin plastic sheet that reduces the penetration of the sun’s heat and subsequently reduces the amount of heat that enters your home during summer. It also reduces the heat that leaves your home during winter, keeping your home warm.

It’s relatively easy to install, though one should ensure bubbles do not form during application. Window films can help you reduce your energy bill by 25 percent.

Cellular Shades

Cellular shades are great for insulating windows. They have cell pockets that look like a honeycomb when you view them from the side and are available in single, double, or triple cell layers. The more the number of cell layers, the better the insulation.

With a wide array of textures and colors, their crisp pleats add an attractive style décor to a room. 

These shades can be controlled manually or automatically from the couch using a remote control, wall switch, your phone, or Google home.

Draft Snakes

This is a simple form of insulation that is made from cloth shaped into a long tube so that it looks like a snake. It is stuffed with beans, rice, batting, or other material.

It is laid around the window, acting like weather-stripping to stop cold air from entering, and warm air from escaping.

Draft snakes are available in shops, but you can make them at home. They are super easy and can be fun to make. All you have to do is sew them slightly longer than the width and height of the windows for maximum insulation.

Black-out Curtains

Click here to see these blackout curtains on Amazon.

A blackout curtain blocks light from entering your home, creating a cooling effect, and preventing warm air from escaping. This is possible because they are made from dense or tightly woven fabric like velvet or suede.

You need to observe caution when cleaning them as they cannot be bleached, ironed, or washed in a washing machine. Instead, they are cleaned on the spot by steaming them or using a damp cloth. Following the instructions on the label will prevent damage to your curtains.

Can You Transform Your Glass Window Into An Insulated Window?

If you do not mind spending a hefty amount on insulating your home, then a good option for you is to replace your current windows with double or triple-glazed windows to fully insulate them. 

Alternatively, instead of replacing, you can add new panes onto your current window. However, there are exceptions to this rule if the frames are warped, the windows cannot open easily, are hard to clean, and are outdated.

When you do this, you will not need to use the insulation methods described above because your windows will insulate your home effectively. 

These windows are constructed with at least 2 panes, with a spacer material and gas sealed in the middle. Sometimes 3 panes are used for extra insulation. The spacer material can either be metal, the most common being aluminum, or non-metal such as composite.

Whereas double or triple glazed windows provide excellent insulation in your home, let us have a look at the pros and cons of the double-glazed windows as shown in the table below:

Pros Cons
Significantly reduced energy bills High installation costs
Decreased noise pollution Difficult to repair
Improved security Not suitable for all homes, especially  the older more traditional homes
Improved aesthetics
Decreased  condensation

Can You Insulate Leaded Glass Windows?

Leaded glass is a type of glass in which lead oxide has been added with a content of between 18 to 40 percent, replacing the calcium content, and is mostly used for decorating or improving the functionality of a room. An example of where they are mostly installed is in the bathroom and kitchen. 

Lead glass windows are sometimes confused with stained glass windows because they look alike. The difference is that leaded glass is clearer, while the stained glass is constructed using different colored or stained glasses together.

Lead glass or stained glass windows can be insulated by sandwiching them between two clear panels. As you already know, every addition of a glass pane increases the insulation of a window.

Below is a video that explains how a lead glass or stained glass is insulated:

In Closing

Construction worker putting sealing foam tape on window in house

If you have insulated your home, but there are drafts of air you feel coming in through your window, then you may have to insulate them. While there are several ways of insulating a window, you only need to identify the most suitable and affordable.

The most expensive method but highly energy-efficient is the transformation of your windows into insulated windows or actual replacement with ready-made insulated windows.

Lead glass windows are sometimes confused with stained windows that can be insulated by sticking a clear glass pane on each side.

Before you go, you may want to read our previous posts and compare the methods used to insulate windows in a basement and windows in a newly constructed home:

How To Insulate Basement Windows

Insulating New Construction Windows

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