The Metrics for Choosing Energy-Efficient Replacement Windows
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The Metrics for Choosing Energy-Efficient Replacement Windows

Almost every window replacement manufacturer nowadays offers energy-efficient replacement windows. The challenge now is not just in buying them, but in making sure you’re choosing the right ones for your home. Here are the metrics to use when choosing energy-efficient replacement windows.

Window Replacement


Traditionally, windows were problem spots because they’re mostly made of glass, a naturally-conductive material, which made them the least-insulated parts of every house. Energy-efficient replacement windows are equipped with insulated glass, which consists of two glass panels that form separate interior and exterior surfaces. A window’s insulation is measured with its U-factor. The lower the value, the better the insulation. Some windows are rated with R-value, which measures resistance to thermal transfer. This means a window with a low U-factor will have a high R-value.

Solar Heat Gain

Insulation reduces heat gain from radiant heat. But windows are mostly made of glass, which means it can still allow solar heat through them. This is why energy-efficient window glass, like our High Performance™ Low-E4® glass, has a layer of coating that selectively blocks ultraviolet (UV) radiation and solar heat. When looking for replacement windows, particularly windows with large glass areas like casement windows, choose those with low solar heat gain coefficient (SHGC) values.

Natural Lighting

One of the main reasons why windows exist is because humans need natural lighting. In addition to its practical and aesthetic benefits, natural lighting can be beneficial to your health. It can help promote healthy amounts of rest by regulating sleep cycles, which can help reduce stress and improve productivity.

As described above, you can find energy-efficient windows that allow natural light in without solar heat gain. When choosing replacement windows consider how much natural light a particular part of the house is receiving. If it’s receiving sunlight that’s too harsh, then choose windows with middle-to-low visible transmittance (VT) ratings. North-facing windows tend to receive lighting that’s more pleasing to the eye and should have windows with high VT ratings.

Renewal by Andersen® of San Diego is your leading provider of energy-efficient replacement window styles, including double hung windows. Give us a call at (858) 935-8451. You can also fill out our contact form to schedule an appointment. We serve customers in San Diego, CA, and the surrounding communities.