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What Do U-values and R-values Really Mean?

2/1/2014 2:26:04 PM

If you have been shopping for replacement windows for your home or are considering a more extensive remodeling project, you have likely seen the R-value and U-value advertised, but what are these ratings and what do they mean? Unless you are a contractor or well-versed in construction terminology, these numbers are probably useless to you without explanation.

In the sections below, we’ll explain what both the R-value and U-value are and why they are important when you are shopping for windows.

What is U-Value and Why is it Important?

U-value measures how well building materials conduct heat. It is essentially the inverse of the R-value. The U-value measures the rate at which heat transfers through a building material over a given area under standardized conditions.

Windows themselves are not measured by R-value because they are not insulating materials by design. They do, however, have insulating materials incorporated into them and have insulating properties, so there needs to be a measurement of comparison for energy efficiency between different window styles. This is measured in U-value. A lower U-value indicates a more energy efficient window.

What is R-Value and Why is it Important?

The R-value is a measurement of heat loss characteristics of a building component. For example increasing the thickness or density of an insulating material increases the R-value.

In short, the R-value measures the insulation properties of a given material. Although R-value is not used to assess windows, it is still important when shopping for windows because materials like wood, fiberglass, and vinyl have R-value ratings.

Comparing the R-value of the materials found in the window’s framing can give you a pretty good indication of how well the different types of window frames insulate compared to the others.

Energy Efficient Windows & Doors By Weather Shield

If you are looking to buy energy efficient windows or doors for your home, Weather Shield offers a number of highly efficient products. All Weather Shield windows come with a variety of features that can impact U-value, including multiple panes of insulated glass, warm edge spacers, insulated frames, and more.

To learn more about our energy efficient glass solutions (available on all products), click here .

To learn more about our energy efficient window and door products, download our product catalogs below:

Product Catalogs

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Aspire Series Catalog

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Signature Series Catalog

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Premium Series Catalog

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