What to Look for in Window Replacement

Residential windows

Most Americans are constantly looking for ways to save money. There are countless ways to do so, like setting budgets, looking for coupons and deals, cutting down the three daily coffees to just one or two, and more. But there are less obvious ways to save money that are sometimes even more effective than these.

One cost that we all have to deal with is energy. As burdensome as our energy bills might be, we often write them off as a necessary evil we can’t change. While it’s true that we all need energy and that energy costs money, it doesn’t mean we need to spend as much on it as we currently are. There are many ways to reduce energy costs, from simple habitual changes like unplugging devices when not in use, to larger remodeling changes like new window installation.

What to Look for in Replacement Windows

Whether you’re a homeowner, business owner, or both, you can save up to 15% on your yearly energy costs by having a window company replace your old windows with new, energy-efficient windows. But before you call a window company to install new windows, there are a few things to look for in order to choose the best windows for your home or business. These include the energy performance rating, U-factor, and visible transmittance (VT).

Energy Performance Rating

The energy performance rating basically refers to how energy-efficient a particular window is. This rating is a summary of the U-factor and VT, which we’ll discuss further below. The rating also looks at the materials used for the frame, whether or not the window has multiple panes, and if there are gas fills (argon or krypton usually) between the panes, which are more effective at insulating than air. All of these factors play a role in how energy-efficient a window is. The more efficient, the less energy will be wasted, and the more money you will save.


The U-factor is a measurement of the rate of heat loss through a window. Like a golf score, you want this number to be lower. The lower the U-factor, the more resistant the window is to heat flow, making it a better insulator. Unlike golf, however, the range of scores only falls between 0 and 1. A perfect 0 would indicate that no heat is getting in or our of the window. This is, of course, not possible, so most people will want to aim for about a 0.15 U-factor. This number is usually only reached by triple-paned windows, while double-paned windows usually have a U-factor of about 0.3. A good window company will let you know that whether you live in a primarily hot climate or cold climate (or both), a low U-factor is always beneficial. These windows will keep too much heat from entering the home or business, but will also prevent too much heat from escaping.

Visible Transmittance (VT)

Lastly, VT refers to how much visible light passes through a window. This rating, like the U-factor, also falls between 0 and 1. The higher the number, the more light is transmitted. While VT doesn’t play as direct a role in energy saving as the U-factor, it is still significant. A higher VT rating means that daylight is maximized. With more natural light coming through, there is less need for powered lighting, such as lamps. Of course, some people don’t want too much light entering their home, as this contributes to the amount of heat entering the room. In this case, a lower VT would be optimal, as well as investing in some shades that effectively block or hinder sunlight. In short, the VT rating is more subjective when it comes to home and commercial window replacement, and the energy savings derived from it.

There is certainly more to the energy performance rating than these factors, but understanding them will give you a leg up on the window company when you’re getting your quotes done. There is plenty of more information on energy-efficent windows and ways to save on energy costs online if you’re so inclined.

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