Windows and Visible Transmittance

Finding energy-efficient windows for your home is now easy thanks to the ENERGY STAR® blue label, which details the energy performance ratings of your new hardware in five different categories. One of these is visible transmittance (VT).

Renewal by Andersen® of San Francisco, your local window contractor, shares how VT plays a key role in the overall energy efficiency of your home.

Visible Transmittance

VT measures the amount of light the window lets through its glass. The measurement is on a scale of 0 to 1, although the values themselves range between 0.20 to 0.80; the latter being the highest. As a general rule, the higher the visible transmittance, the more light your new window allows.

Why It’s Important

Window contractors like us urge homeowners to look for windows with high visible transmittance as it allows you to offset electric lighting. The more daylight entering your rooms, the less you have to artificially light up your home, which translates to savings in your electric bill.

VT and Light to Solar Gain Ratio

Originally, windows that reduced solar gain through the use of tints and coatings also reduced its VT. More often than not, you had to balance what was more important – less heat or more light?

Advances in glass technology no longer force you to choose between the two, thanks to the ability of high-performance and low-emissivity (Low-E) glass to reduce solar heat gain while still providing ample daylight. At Renewal by Andersen of San Francisco, we offer a range of High-Performance™ Low-E4® Glass that is 56% more energy-efficient during summer and 47% more energy-efficient in winter than ordinary double-pane glass.

As one of the top window companies in San Francisco, you can count on us to properly install your new windows. Call us today at 866-609-5033 to learn more about our services. We are local window contractors in San Francisco.