How to Find the Energy Efficiency of Windows in Your Home

Windows are a defining feature of homes, giving houses personality and natural lighting to bring them to life. They also give us a barrier between the comfort of our homes and the outside world, allowing us to control the temperatures of our homes by opening or closing them.

But many windows aren’t efficient, leaking hot air into the house and letting cool air out. This increases energy costs, makes your home less comfortable and may lead to more problems down the line. In this article, we’ll go over inspecting your windows for problems and how to check the energy efficiency of windows in your home.

Energy Efficiency of Windows: Checking the Components of Your Windows

In order to check the energy efficiency of your windows, you need to inspect the components of your windows. This is to find out what type of windows you have, but also to see if the components of your window are performing correctly and haven’t deteriorated.

Some windows will have an energy rating called a “U value” that is given by the manufacturer. A low U value means better energy efficiency, so check your window warranty or model to find out it’s U rating.


The first step in inspecting the components of your windows is to inspect the frame and see what type of material it is. There are three main types of window frames: aluminium, wood, and vinyl. Each has its own energy efficiency and lifetime, so its important to know what type of windows you have.


aluminium frame windows are easy to identify based on their appearance and feel. They will be painted to cover the metal frame and will have a different texture than wood. aluminium frames are generally cheaper and more durable than other windows but are not as energy efficient.

This is because aluminium conducts heat and will heat up quickly on a hot day, passing heat into your house. When aluminium frames heat up they can also warp or bow due to the weight of the glass window, which creates gaps in the window and passes even more heat into your home.


Wood frame windows will usually be thicker than aluminium windows and heavier than vinyl windows, with a painted and wood-grain textured surface. Many people like the appearance of wood windows because they offer a more classic look with thicker frames.

Wood windows are the most expensive type of window because the wood must be cut and shaped perfectly to fit the opening, which is an expensive process. They are more energy efficient than aluminium windows, but they also are more likely to warp and bow due to wood’s sensitivity to humidity.

If you live on the coast wood windows are not a good choice because the humidity will cause them to rot. Wood windows also require more maintenance and therefore are more expensive to keep on your house.


Vinyl windows are made out of a colored plastic polymer and will appear smooth and have a hard plastic feel to them. Vinyl frame windows are the most energy efficient material because they don’t conduct heat well and are resistant to elements such as humidity.

Vinyl windows are tough and are less likely to warp and bow like other window frames. They can still warp and bow over time if they are exposed to extreme heat, but vinyl windows with a metal reinforcement will not bend or warp like other vinyl windows.

Frames and Energy Efficiency

There are a couple of tests you can do to check if your frames are energy efficient. First, get eye level with your window and look at the area where the frame meets the sash of the window.

If you can see daylight through any spaces or gaps between the frame and the sash, then your window frame is warped. This means that air is coming through those gaps and cool air is leaving your home and hot air is coming in. You can also check the lock on your window. If the lock doesn’t line up or doesn’t latch, it can also be a sign that your frame is warped.

Make sure to look for any rusting, rotting, or cracking in your window frames. Any kind of deterioration of the frame is a sign that there is something wrong on the inside of the frame and means that the window is no longer energy efficient.

Window Glass

Figuring out what type of glass you have in your windows is an important part of finding out the energy efficiency. The type of glass you have and the number of panes affects the energy efficiency of your window.

Glass Coating

Some windows have a “low e” coating, which is a reflective coating that directs energy from the sun away from the inside of your house. This doesn’t affect the view out of your windows, as the coating is nearly invisible.

If your windows have a slight tint to them or the window frame has lettering that says, “low e”, then your windows have a reflective coating and are more energy efficient than non-coated windows.

Single Pane V.S. Double Pane

The number of panes you have in your window is the number of sheets, or “panes” of glass in the window, which come in single or double paned glass. Single pane glass is less energy efficient than double pane glass because it does not absorb as much solar radiation as two layers of glass.

You can identify single pane glass windows by holding a flame or light in front of the glass; if you see two reflections, you have double pane glass, if you see one reflection, you have single pane glass.

Glass and Energy Efficiency

To test the energy efficiency of your glass, there is a simple test you can do. During a sunny part of the day, open the window and let your hand sit in the sun for a few minutes. After your hand has felt the temperature and warmed up, shut the window and hold your hand in the sunlight that is coming through the window.

If you don’t feel a significant drop in temperature and intensity of the heat, then your windows aren’t energy efficient. Another quick test is to check for any condensation or water stains on the inside of your windows; if you spot any, it means the seals on the inside of the window have failed and is no longer energy efficient.

Stay Cool

As you can see, there are plenty of ways to lose the energy efficiency of windows in your home and make your energy bill skyrocket. The best way to ensure your home and windows are energy efficient is to inspect them regularly and replace them with more energy efficient products.

If you have any questions about how to keep your home cool this summer or energy efficient windows, please visit our site.

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