The Solar heat gain coefficient (SHGC) is one of the two most important energy performance ratings for window systems. If you’re serious about lowering your cooling costs, you can use this measurement to determine your best options.
Here’s how SHGC separates high-performance windows from less efficient ones:
It Defines the Window’s Solar Heat Resistance
Expressed in numbers ranging from 0 to 1, lower values are better. The National Fenestration Rating Council (NFRC) measures the SHGC of the unit based on the entire window, not only on the glass. In other words, the NFRC label shows how much infrared light from the sun can pass through the unit, including the effect of the frames.
The appropriate SHGC for your window depends on your location. In Tarrant, Dallas, Collin, Denton, Kaufman and Rockwall counties, the lowest SHGC value your windows should have is 0.25. Glazed patio doors should also have an SHGC of 0.25 or less to prevent solar heat gain effectively.
It Determines the Optimum U-factor Value
For maximum energy efficiency, choose windows with the right combination of U-factor and SHGC. U-factor is a measurement of the unit’s ability to insulate heat. Like SHGC, lower values are better. The interplay between these two ratings ultimately determines which ENERGY STAR®-labeled products are right for your home. In the South-Central Climate Zone, the best-performing windows are those with a 0.25 SHGC (or less) and a 0.30 U-factor (or less).
It Decreases Visible Light Transfer
Although it’s tempting to buy windows with the lowest SHGC, understand that lower ratings can affect how much visible light the window admits into the home. Since increased daylighting is a practical home improvement goal, keep an eye on the product’s Visible Transmittance (VT) rating too. Without going beyond the recommended SHGC and U-factor maximums, choose replacement units with the highest VT value to enjoy more sunshine and clearer views.
Renewal by Andersen Dallas and Fort Worth products have a healthy trade-off among infrared reflectivity, thermal insulation and visible light transfer. We also offer different glass options with different combinations of energy ratings to help you achieve your window replacement goals more easily.
Call us at (877) 605-2922 to schedule your FREE, in-home consultation, and let’s talk about your project. We serve Fort Worth, TX, and the surrounding communities.