How Much Energy Efficiency Do Your Windows Really Need?

From Brittany on April 7th, 2011 in Window Replacement

Much confusion surrounds energy efficient windows. You know that they’re fantastic and save you money on energy bills, but how much efficiency do you really need to keep your home a comfortable temperature? And how much is too much? Let’s get clear this up once and for all.

To find out how much replacement windows cost in your area, click here.

In general, triple-pane windows are only necessary for regions that see extreme heat or cold. For most everyone else, double-pane windows with Low-E coating are just fine.

1. Locate Your Climate Zone

Next, decide your level of glass pane efficiency. Each climate zone in the U.S. has different requirements for window glass. So first things first, which climate zone do you live in? (You can also search by zip code at Energy Star.)

2. Jot Down Your Recommended Window Ratings

Here’s a breakdown of how well replacement windows should perform based on your climate zone. Washington, D.C., for example, is in the North-Central Zone, and therefore needs a window with U-factor of 0.32 or less. U-factors and other rating numbers will be printed on all Energy Star certified windows. This makes it easy to see how different products measure up.

• North-Central Zone: U-factor of 0.32 or less, and SHGC of 0.40 or less
• Northern: You can do one of three options: U-factor of 0.30 or less with any SHGC; or U-factor of 0.31 and SHGC of 0.35 or higher; or lastly, U-factor of 0.32 and SHGC of 0.40 or higher
• South-Central: U-factor of 0.35 or less, and SHGC of 0.30 or less
• Southern: U-factor of 0.60 or less, and SHGC of 0.27 or less

U-Factor, if you’re curious, measures how well your window insulates. It ranges from 0.25 to 1.25. The lower the number, the better the window keeps your home heated.

SHGC measures how much heat is blocked by your window, and ranges from about 0.25 to 0.80. The lower the number, the less solar heat is allowed to pass through. This is why super-sunny Florida, for example, requires an SHGC of .027 or less, and frigidly cold Wisconsin needs only a 0.40 or less.

3. Find an Experienced Window Installer

Replacement windows are only as good as the contractor that installs them. In fact, a poorly sealed window will often void the warranty that came with your purchase, leading to all kinds of difficulties and costly repairs.

You can find an experienced window contractor by clicking here. They are guaranteed to be:

• Pre-screened, licensed and insured
• Local to you for lower costs
• Ready to complete the work on your schedule

The best-performing windows are airtight and will last for years. Make your investment count the first time by following these steps, and then of course, let us know how you love your new windows.

Photos via Houzz