This article is the second in a series of 15 articles where we “decode” some of the industry terms surrounding replacement windows. Stay tuned for upcoming posts that we hope will help educate San Diego homeowners and allow them to make more informed decisions.
The window industry (technically the “glazing” industry) has a language all to its own. If you’ve ever looked at replacement windows in a home improvement store or talked to a replacement window salesperson, you probably saw or heard terms that were completely unfamiliar to you. Phrases like “U-factor” or “Solar Heat Gain Coefficient” are not ones you hear every day, but are important to understand if energy efficiency is an important characteristic in the replacement windows you are looking to purchase.
So, what do these terms mean? What do their corresponding ratings mean for the energy efficiency of the products they’re attached to? Read on, and we’ll try to “decode” some of the most important terms for San Diego homeowners to understand that are related to the energy efficiency of replacement windows and doors.
Solar Heat Gain Coefficient (SHGC)
A window’s solar heat gain coefficient measures how resistant a window or door is to allowing unwanted heat to pass through it into the home. SHGC numbers fall between 0 and 1, with a lower number being more desirable. Windows and doors with a low SHGC number are especially critical for homes located in areas that see higher temperatures, such as the inland areas of San Diego county.
The U-Factor number indicates how well a window or door prevents heat from escaping the home. U-Factor numbers range from 0.20 to 1.20, with a lower number being better. While you want a window with a good U-Factor rating, it is not as critical as buying windows with a good SHGC rating, since San Diego county doesn’t experience particularly cold winters that necessitate windows that hold the heat in well.
This one is a little more self-explanatory. The Air Leakage number tells you how much air is allowed to enter the home through the window or door product. Air leakage numbers fall in the range of 0.1 to 0.3. Look for a lower number, as it means fewer drafts will be allowed into your home.
ENERGY STAR is not a term that is specific to the replacement window and door industry, but you’ll see the ENERGY STAR label on many of the window and door products on the market. This blue label indicates that the product has been certified by the Environmental Protection Agency (EPA) of the federal government and meets or exceeds their standards of energy efficiency. It’s important to buy products that are ENERGY STAR certified if you want to take advantage of any government rebates that may be offered for installing energy efficient products in your home.
An important note to add to all of this: the energy efficiency ratings of the windows and doors you purchase don’t mean anything if the person installing them does a poor job or uses subpar materials in the installation. You could buy windows with the very best SHGC rating on the market, but if they are improperly installed, you won’t see the energy savings you were hoping for. Therefore, it’s important to hire a San Diego replacement window company that uses experienced replacement window installers.