Rated Five Star on Google!

Call Or Text

Virtual Estimate

Window Replacement Company in NJ

Understanding Energy Ratings for Windows: What You Need to Know

What Makes a Vinyl Window Weather Resistant?

Window Energy Ratings provide a way to compare the energy efficiency of various window products. Choosing the right windows for your home can significantly impact both the warmth and security of your living spaces. Energy Star ratings help you understand which windows are energy-efficient.

Window ratings assess how effectively windows perform in terms of energy efficiency and other factors. The National Fenestration Rating Council (NFRC) is the foremost organization responsible for developing and certifying these ratings in the United States.

Window ratings are crucial as they guide consumers in selecting the right windows for their homes and specific climates. Energy-efficient windows can significantly reduce energy bills, lower carbon footprints, and enhance home comfort.

Every NFRC-certified window features a label displaying its window ratings, manufacturer information, model number, and size. These ratings are the most reliable and are used by the U.S. Environmental Protection Agency’s ENERGY STAR® program to evaluate windows. They are essential for consumers as they enable product comparisons and informed purchasing decisions. Moreover, replacing old windows with ENERGY STAR-certified products can reduce a home’s utility bills by an average of 13%.

Why Are Window Ratings Important?

Window ratings play a crucial role for consumers by guiding them in selecting windows that suit their home and climate. These ratings also contribute to saving on energy bills, minimizing their carbon footprint, and enhancing the overall comfort of their living space.

Energy Performance Ratings

By understanding window ratings, consumers can decide which windows to purchase for their homes.

The NFRC evaluates three mandatory window efficiency ratings for all windows, and it’s important to understand that lower or higher ratings for each area aren’t necessarily better or worse for your home. The optimal ratings depend on your location and the amount of sunlight your windows receive. Additionally, the NFRC’s rating system includes two optional ratings that assess efficiency in areas other than energy use.


This mandatory rating measures the amount of heat inside your home that can escape through a window. It is displayed as the top-left number on all NFRC labels. A lower U-factor indicates better insulation properties, meaning the window is more effective at keeping heat inside your home, which is particularly beneficial in colder climates.

U-factor should not be confused with R-value, which is another common measurement of a home’s energy efficiency. R-value measures the effectiveness of insulation in other parts of a building’s exterior shell, such as walls, roofs, and floors, and anything else that acts as a barrier between outside and inside. Unlike U-factor, for which a lower number is better, a higher R-value indicates better performance for the various elements that insulate a home. Efficient windows with a low U-factor offer several benefits, including lower monthly utility bills, savings on heating-and-cooling equipment, and enhanced comfort control.


This mandatory rating measures the amount of solar heat sun that can enter a home through a window and is the top-right number on all NFRC labels.

The appropriate ratings for your home depend on your climate and the orientation of each window. A lower Solar Heat Gain Coefficient (SHGC) rating promotes energy efficiency in hot climates by reducing the amount of heat gained from the sun, particularly in rooms exposed to afternoon sunlight. Windows with low SHGC ratings offer benefits such as lower monthly utility bills, savings on heating and cooling costs, and improved control over indoor comfort levels.


This mandatory rating measures the amount of solar light that can enter a home through a window. The rating can be found on the middle or bottom row of an NFRC label on the left side.

Efficient windows can harness natural light while mitigating unwanted heat, achieved through reflective coatings on the glass surface. Various treatments like low-emissivity (low-e) coatings, tints, and films offer options to control the amount of light and heat entering your home. High-visible transmittance efficient windows provide benefits such as increased natural light, reduced monthly utility bills, and added protection against fading of furniture, artwork, or wood floors.


This optional rating measures the volume of air that can infiltrate a home through a window. This rating can be found on the middle or bottom row of an NFRC label on the right side.

The benefits of low air leakage include lower monthly utility bills, fewer cold air drafts, control comfort, and reduced street noise and other external sounds.


This optional rating measures a window’s ability to prevent moisture on the interior of a window. This rating can be found on the bottom row of the NFRC label on the left side.

Condensation on the outside of a window is generally less worrisome than condensation on its interior surface. Inside condensation occurs when the temperature of the interior glass surface is lower than the room’s dew point, causing moisture droplets to form. Efficient windows with higher condensation resistance ratings offer benefits such as protection against cold drafts, mold, and mildew, as well as enhanced comfort control.

To determine a window’s energy performance, you should check its window energy ratings. These ratings help you understand how energy-efficient the windows are rated to be. Knowing the window rating can help you determine if the windows have high energy performance.

If you are looking for contractors for your upcoming home renovation project at New America Construction we provide windows estimates for all NJ homeowners.

Call us for more information 973-804-9400 

Find us in:

FacebookInstagramGoogle and Yelp


Get Your Free Quote Today!

Fill out the contact form below and a representative will be reaching out to you shortly. Or call (973) 804-9400