The Window Source of the Tri-Cities

3036 Highway 75 Kingsport, TN 37663

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What is an NFRC Rating?

Each year, the average American household spends $1,500–2,500 on energy bills. 45% of that cost is for heating and cooling. Choosing high-performance windows, doors, and skylights can save you money and keep your home comfortable.

©2020 National Fenestration Rating Council

The NFRC Rating is an Energy Performance Label.

All Window Source products come with voluntary National Fenestration Rating Council (NFRC) labels so that you can compare window products with confidence. You can rely on the labels and forget about all the sales gimmicks that you may hear from companies charging much higher prices. In fact, the United States Environmental Protection Agency (EPA) relies on NFRC data to set its ENERGY STAR guidelines.

The National Fenestration Rating Council is committed to advancing the continuous improvement of windows, doors, and skylights, contributing to making buildings more comfortable and energy-efficient.

The displayed NFRC is based on the 9000 Series Double Hung Window and may vary on size, series, type, and options.

What does the NFRC Label Tell You?

The NFRC label indicates measurable elements of window energy efficiency performance such as U-Factor, Visible Transmittance, Solar Heat Gain Coefficient, and Air Leakage

U-Factor measures how well a product can keep heat from escaping from the inside of a room. The lower the number, the better a product is at keeping heat in. 

Range: 0.20-1.20 Look for: Low numbers

Visible Transmittance measures how well a product is designed to effectively light your home with daylight, potentially saving you money on artificial lighting. The higher the number, the more natural light is let in. 

Range: 0-1 Look for: High numbers

Solar Heat Gain Coefficient measures how well a product can resist unwanted heat gain, which is especially important during summer cooling season. The lower the number, the less you’ll spend on cooling. 

Range: 0-1  Look for: Low numbers

Air Leakage measures how much air will enter a room through a product. The lower the number, the fewer drafts you’ll experience. 

Range:  ≤ 0.3  Look for: Low numbers

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See What Our Customers Are Saying About Us

“I love my new windows! The whole experience from placing the order to installation has been great. The windows are very well made and was exactly what I wanted. It is nice to deal with people who are honest, hard working, and stand behind their products. Great job guys!”

Sandra Waldon; Blountville TN

“From the professionalism of Duane, the owner, to the perfection of the window installer – Joe-it has been an all around wonderful experience. The windows are gorgeous! My custom entry door is beyond what I could have imagined.”

Shelly Good; Johnson City TN

“The BEST team I have ever worked with! 5 STARS!”

Susan Smith; Johnson City, TN

“Provided us with great quality windows for our church parsonage. Very quick in order process and installation.”

Ruthie Williams; Flag Pond, TN

“Went above and beyond.  Love our new windows.  Couldn’t be more pleased.”

MW; Kingsport, TN