Today’s technology is so evolved that there are numerous ratings for various appliances and products to help you better evaluate them according to your needs. Windows are no different. Depending on their instalment, there are some acronyms that will guide you to buy exactly the product you need. But do you know what they mean? Don’t worry, in this article, we’ll make it easy for you.
This rating refers to the speed with which a window allows non solar heat to pass through it. For a greater energy efficiency the U-factor has to be low. The lower, the better.
SHGC stands for solar heat-gain coefficient and refers to the amount of solar radiation a window allows to pass through it. According to the climate you live in, you may need either a higher SHGC or a lower one. The lower it is, the less solar heat can pass through the window, so these windows are suitable for hotter areas. If the SHGC is high, this means that a lot of solar heat will go through the window, so you should look for them if you live in colder climates.
Air leakage
Just like in the case of U-factor and SHGC, the lower the number, the better. It means that the air leaks slower if the number’s value is lower.
VT stands for visible transmittance and refers to the amount of light that your windows let pass through their panes. If the VT is higher, the light is more visible, if it’s lower, the windows will reduce the glare.
Light-to-solar gain is the relationship between SHGC and VT. This rating will give you an idea of the efficiency of your window with respect to how much light it lets in, and how much heat is being blocked, at the same time. So, for example, if you live in a hot climate and you are interested in buying a window with a high LSG. You’ll get plenty of light, but heat won’t bother you.