
Reading the NFRC Label
Most new windows carry a National Fenestration Rating Council (NFRC) label. Two numbers matter most:
| Rating | What it measures | For Oklahoma |
|---|---|---|
| U-factor | How much heat passes through the whole window | Lower is better, year-round |
| Solar Heat Gain Coefficient (SHGC) | How much of the sun’s heat gets through the glass | Lower helps a lot on west and south walls in summer |
| Visible Transmittance | How much light gets through | Higher means brighter rooms |
| Air Leakage | How much air gets past the window | Lower is better |
ENERGY STAR Climate Zones
ENERGY STAR sets different U-factor and SHGC limits by climate zone and shows a map on the label. Much of Oklahoma falls in the South-Central zone. Check that the product you’re quoted is certified for your zone, not just “ENERGY STAR” somewhere.
Upgrades That Make a Difference
- Low-E coating. A thin metal-oxide layer that reflects heat. HomeGuide says it adds 10% to 20% to the window price. A low-SHGC Low-E coating helps most on sunny sides of the house.
- Argon or krypton gas fill between the panes slows heat transfer.
- Warm-edge spacers reduce condensation at the edge of the glass.
- Triple pane. Helps with noise and cold, but often costs more than it saves in a hot-summer climate. Ask for both prices.
- Installation. A well-rated window installed with gaps around it still leaks. Ask how they insulate and seal the opening.

Tax Credits and Rebates
Federal energy-efficiency tax credit rules have changed recently. Before counting on a credit or utility rebate, confirm current eligibility with IRS.gov, your utility, or a tax professional. Installers aren’t tax advisors.
Will New Windows Lower My Bill?
It depends on what you’re replacing, how many windows face the sun, and how the rest of the house is insulated. Be skeptical of any specific savings promise in a sales pitch. Ask how it was calculated.
See prices in the cost guide, or compare frame materials on the vinyl windows page.
Request a Window Replacement Quote
Tell us about the windows. A local Broken Arrow-area window company will call or text you back to set up a measurement and written estimate.
Please note: Broken Arrow Window Replacement connects homeowners with independent local window installers. We are not a contractor and do not do the work.