Everything You Need to Know About Replacement Windows


Roughly 30% of the average home’s heat is lost through poorly-insulated windows. And it’s not just a wintertime problem—during the summer, you’re losing energy as cool air escapes through the windows, making it necessary to run your air conditioner more.

With this being the case, the incentives to install windows and replace your old, inefficient ones are there. But so are a plethora of options for replacement windows. With so many choices, how it can be hard to know what to do.

If you’re ready to hire commercial window installers to install windows in your home, this guide can help you figure out what to do. Read on to learn what to look for in good windows.

What Makes Up a Good Window?

First of all, it’s good to know that practically any new window you find will be made with at least two panes of glass, which make up the glazing. Only windows made specifically for unheated buildings and areas, like garages and outbuildings, are likely to have just one pane of glass.

Two-pane glass, or insulated glass, has proven to be very helpful over the last few decades since it came into common use. By sandwiching the air between two separate, sealed panes, the insulative value of the glazing is increased several times over.

More recently, manufacturers have started sealing dense, insulating gases into windows between their panes, such as krypton and argon. This makes windows even more insulating than those that have plain air sealed inside them.

While on the assembly line, window glass is sometimes coated with films of a nearly invisible substance, such as Low-e metallic oxides, which can provide additional insulating properties—such as solar heat reduction or improved heat retention.

The sash holding the glazing also plays an important role in a window’s efficiency. Materials like fiberglass, wood, and vinyl (either hollow or insulated) provide very low heat conductance, thus reducing the transfer of temperatures from one side of the window to the other.

Improvements like these make replacement windows and new ones more energy-efficient than ever. And the improvements aren’t just measurable using special instruments and thermometers—just by sitting or standing next to a window, you can feel the difference.

Being next to a single-pane window can give you a noticeable chill, even if the house is technically quite warm. This is because your own body heat is radiating out through the window—the heat your body is generating literally gets sapped out of you! However, with energy-efficient glazing, the inner pane of glass is kept warmer—and this actually reflects your own heat back to you.

In addition to the above technical factors, another factor to look at when you’re ready to buy and install windows is the rating given to windows you’re considering.

The National Fenestration Rating Council rates certain manufacturer’s windows, taking into account things like air leakage, U-factor (which represents a window’s rate of heat loss), solar-heat-gain coefficient (the most heat gain possible from sunlight shining through that window), and visual transmittance (how much light the window allows in).

Labels like these, placed on new window packaging by the Council, can let you know what to expect from the window once you have it in your home. Besides telling you which windows are the most energy-efficient for the money, this information also helps you choose certain windows based on where in the house you need them. Different windows are designed to deal with different levels of heat and sunlight. Selecting each window will depend on where around your home sunlight is going to be at different times of the day.

Install Windows Right

Window installation is complicated. For good windows to provide the maximum energy efficiency, they have to be installed correctly. It won’t matter that your window is air-tight if there are cracks where your walls and windows meet.

Anyone who has lived in a very old house has seen how strong winds outside can cause the curtains to move because of leaky windows. This is an experience you don’t want to see after buying and installing new, state-of-the-art windows in your home.

Because of this, it’s very important that you don’t hire the first local contractor you find, unless they have verifiable experience with happy customers and the appropriate certification.