Reading and Understanding NFRC Window Labels, Part 1

When considering new windows for a home or business, efficiency is one of the top factors you’ll be thinking about. Efficiency refers to how well a given window stops air transfer from inside a building to outside it, plus areas detailing light that passes through and other important areas.

At Peach Building Products, we’re a trusted window supplier by several industry standard-setters, including the NFRC – the National Fenestration Rating Council. All window manufacturers must include a label from this organization, one known as the NFRC label, which contains various energy performance indicators that tell you exactly what you can expect from your window when you purchase it. In this two-part blog, we’ll go over every element that will or might be present on your NFRC label, and what each area is meant to tell you.

NFRC Window Labels

Basic Description

Every NFRC label will contain a basic product description at the top, detailing some very simple information. Areas that will be included in this description include:

  • Name of the window manufacturer
  • Material used for the window frame – vinyl, wood, aluminum, fiberglass, composite or other
  • Gas in-fill, if used – generally argon or krypton gas, for double- and triple-pane windows
  • Glazing type – single, double, or triple-pane glass
  • If applicable, Low-E coating type
  • Which style the window uses to operate – awning, sliding, casement, double-hung or other

U-Factor Rating

From here, your NFRC label will get into a bunch of specific performance rating variables you might want to consider. The first of these is known as U-factor, a number that speaks to how well the window prevents heat from passing through.

U-factor ratings operate on a scale ranging from 0.02 all the way up to 1.20. This is an inverse quality number, however – the lower the rating, the better the window is at insulating against heat loss. Naturally, windows with lower U-factor numbers, and therefore better insulation, will generally cost a bit more than those with higher U-factor ratings, assuming other factors are equal.

One thing that many homeowners don’t realize is that the federal government and local utility companies offer rebates or tax credits based on the U-factor rating that can help pay for the upgraded U-factor rating.

Solar Heat Gain Coefficient

Located just to the right of the U-Factor on your NFRC label will be another important piece of information known as Solar Heat Gain Coefficient (abbreviated SHGC). This is a measure that speaks to how well the window prevents radiant heat gain when exposed to direct sunlight.

The rating scale is a bit simpler for SHGC than U-factor – it begins at 0 and moves up to 1. But like U-factor, it’s an inverse number: The lower the rating, the less solar heat transfers from outside to inside, meaning your window is more efficient during summer periods where this heat transfer can have a big impact on your cooling costs.

For more on important areas of your NFRC window label to be aware of, or to learn about any of our new windows, entry doors or custom options, speak to the pros at Peach Building Products today.