If you’re in the market for new windows for your home and business in the US, you’ve likely come across the NFRC, a council that provides energy ratings for windows, doors, and skylights. In this quick article, we’re going to explain everything you need to know about NFRC and NFRC ratings, and how they’re important for your shopping experience.
NFRC Explained
What is the NFRC?
NFRC stands for National Fenestration Rating Council. If you’ve never heard of fenestration, don’t worry — for our purposes it means windows, doors, and skylights.
What does the NFRC do?
The NFRC provides energy ratings for windows, doors, and skylights with regard to their energy efficiency, or energy performance. In other words, they provide a standardized measure for how good your doors and windows are at preventing heat transfer from the interior to exterior of your home or business and vice versa.
This way, builders, homeowners, and state and local regulators have a quick and easy way to understand how installation of a particular door or window will impact a building’s overall energy efficiency, which is important when setting and abiding by standards to reduce energy costs while creating comfortable places to live and work.
What is an NFRC Rating?
NFRC ratings energy efficiency scores for doors and windows based on five metrics:
- U-factor - For insulation. Generally ranging from 0.20 to 1.20, this is a measure of non-solar heat flow through a window or door as BTUs per square foot. Lower ratings mean your doors and windows are better at keeping heat in or out, and more energy efficient.
- Solar Heat Gain Coefficient (SHGC) - For cooling. A number between 0 and 1 that measures what percentage of solar radiation passes through a window. Different numbers here will be suitable for different climates, with lower numbers preferred for reducing heat transfer in hotter regions, and higher numbers for solar heating in colder climes.
- Visible Transmittance - For natural light. A measurement between 0 and 1 of how much visible light passes through a window as a percentage. Higher ratings mean more light.
- Air Leakage - For drafts. A number between 0.1 and 0.3 that indicates how much air passes through a window. Ratings below 0.3 are considered energy efficient.
- Condensation Resistance - For moisture. A rating between 1 and 100 that measures how good windows are at preventing the build up of moisture on the glass. Ratings between 30 and 80 are generally considered good. This is particularly important in cold-weather regions, where condensation can pool inside your home, causing costly damage to your walls and floor.
Are all windows NFRC Rated?
No, not all windows receive NFRC ratings. NFRC Ratings are only given after a manufacturer submits their window designs to a certified testing laboratory for review. The windows then undergo both computer-simulated and real-world evaluation in order to determine what their ratings will be.
NFRC ratings are a prerequisite of ENERGY STAR certifications, so all ENERGY STAR windows will also have an NFRC rating.
Why are NFRC Ratings Important?
NFRC ratings are important for two main reasons.
First, they enable consumers to shop informed and with confidence. By understanding NFRC ratings and the factors that affect them, you can rest easy knowing you’re buying a product that has been third-party certified to meet high energy efficiency standards.
Doors and windows are a costly, long-term investment, and not easily or conveniently replaced. Being able to understand a product at a glance, as well as compare it to others in the same category makes the shopping experience much smoother.
Second, having a standardized measure for energy efficiency across the US allows state and local agencies to set minimum requirements that protect consumers, reduce energy costs both at home and on the grid, and help to reduce the impacts of cooling and heating on the environment.
NFRC Requirements and Title 24
In 1978, California passed Title 24, a state Building Standards Code which includes requirements for energy efficiency (Title 24, Part 6).
California’s Energy Efficiency Strategic Plan, which went into affect on January 1, 2020 and relies upon Title 24 standards, aims to achieve Zero Net Energy (ZNE) for all new homes built in the state. Part of those aims will depend on meeting certain NFRC ratings requirements for doors and windows installed in new and existing homes.
Here’s a look at the specific NFRC ratings requirements in California per Title 24:
- U-Factor: 0.30 or less
- Solar Heat Gain Coefficient (SHGC): 0.23 or less
It’s worth noting that the SHGC requirements don’t apply in several of California’s 16 climate zones as defined by the state, specifically in the northern coastal regions and the northern interior, east of Fresno and Sacramento.
FAQs
What is a good NFRC Rating?
Here’s a quick look at good NFRC ratings for each category:
- U-Factor: 0.30 or lower is considered very energy-efficient
- Solar Heat Gain Coefficient (SHGC): 0.25 or lower is considered good in warmer regions, while a range between 0.35 and 0.60 may be preferred for solar heating
- Visible Transmittance: This depends on placement and preference, however ratings lower than 0.45 will be quite dark
- Air Leakage: Ratings below 0.3 are considered energy efficient
- Condensation Resistance: A rating higher than 50 is recommended
What does NFRC certified mean?
An NFRC-certified window or door is one that has been voluntarily submitted by its manufacturer for testing by an accredited third-party laboratory for energy efficiency. It receives ratings for solar and non-solar heat transmission, transmission of visible light, air leakage, and resistance to condensation.
What is the difference between NFRC and ENERGY STAR?
The ENERGY STAR label is an easily recognizable signal to consumers that the product it’s affixed to has been identified as energy efficient by the US EPA and Department of Energy. It can apply to a wide spectrum of products, including windows.
The NFRC (National Fenestration Rating Council) is an organization that provides certifications for energy efficiency specifically for doors, windows and skylights, also known as fenestration.
If a window has the ENERGY STAR label, it:
- has a U-Factor less than 0.20
- has a Solar Heat Gain Coefficient (SHGC) of less than 0.25
- has a North American Fenestration Standard/Specification Performance Grade of 15
- has double or triple-paned glass with inert gases in between
- has insulating window frames
- has spacers to separate the glass panes
- is made with Low Emissivity (Low-E) glass to reflect heat and UV light
Bottom Line
The National Fenestration Rating Council (NFRC) and the ratings they provide are a crucial tool helping consumers make informed decision about the energy efficiency of their doors and windows. Understanding NFRC ratings can make the door and window buying process smoother and lead to fewer regrets when buying these long-term investments in your home, especially in states like California where Title 24 sets minimum standards for overall energy efficiency.
