How Is SHGC Determined?

With windows accounting for a significant portion of a new construction or remodeling project, it’s critical to understand what you’re getting from your supplier. Window styles, frame materials, and glass can all have a significant impact on your home’s overall performance in terms of energy efficiency and comfort. 

When it comes to windows, the topic will inevitably turn to glass and one critical measure of glass for home comfort is the Solar Heat Gain Coefficient or SHGC for short. However, what is SHGC and how did it come to be? How do you determine which items to search for?

In today’s post, exterior remodeling contractor Timberland Exteriors™ explains what SHGC is and how SHGC ratings are determined. 

Solar Heat Gain Coefficient (SHGC)

The Solar Heat Gain Coefficient (SHGC) is another vital rating. The SHGC rating measures how much solar heat passes through the glass into the house. The SHGC rating ranges from 0 to 1, with lower SHGC values allowing less solar heat into the residence. The SHGC and U-ratings have an interesting relative association. Windows with higher SHGC ratings also have higher U-ratings, therefore those seeking natural heating must do it at the sacrifice of insulating value.

Solar Heat Gain Coefficient and Climates

Not all climates have the same heating and cooling goals. In the south, you’ll want a window that can keep out as much heat as possible for most of the year. But in the north, you’ll be more interested in letting in heat, especially during the bitter cold winter months. You’ll want to, generally, choose windows with a low SHGC rating if you live in a warm climate. For windows that are west-facing and south-facing, you might consider low SHGC rated windows to help with that hot afternoon sun. For this scenario, you could choose a rating value as low as 0.25.

If your goal is to let in heat to warm your house with solar energy, however, residential roofing service providers recommend you to choose a window with a higher SHGC rating. This will remove the solar heat-blocking elements so you can enjoy a bask in the warm winter sun and spend less on your heating bill. For the “passive solar” effect, choose an SHGC value between 0.42 and 0.63. For true solar heating, choose the highest value rating you can find.

How are SHGC Ratings Determined?

The National Fenestration Rating Council (NFRC) began testing window products and issuing SHGC ratings in 1993. In addition to windows, skylights, doors, and attachment goods, the NFRC runs the only independent energy rating and labeling system. The U.S. Department of Energy and the EPA use SHGC ratings to assess the energy efficiency of windows for product certification and federal incentive and rebate programs.

Labels on NFRC-certified products show SHGC ratings. The window’s U-factor, air leakage, visual transmittance, and condensation resistance are all listed. These variables combine to define a window’s energy efficiency. The NFRC marks let consumers buy windows that are best suited to specific applications and installations.

When it comes to hail storm damage restoration, Timberland Exteriors always gets the job done! We’re proud to say that we have received numerous awards for our commitment to our workmanship and customers, and our promise to always provide them with the highest quality products. Call us at (651) 374-9858 or (218) 849-6675 for more information. You can also fill out our online contact form! We serve home and business owners in Minnesota including Detroit Lakes, MN.