When it comes to energy efficiency, windows and doors are a big deal: According to some estimates, they can account for up to 50% of energy costs. That’s why, in the state of California, Title 24 compliance is also a big deal. Title 24 is the shorter name for the California Building Energy Efficiency Standards Energy Code, which was established in 1978. The code is reviewed and updated every three years, with the most recent update in 2022.
So what is Title 24? And how does it affect your business? Let’s learn more about the Title 24 window requirements for 2024 and how to find products that make your life easier.
Overview of California’s Title 24 requirements
Title 24 is actually composed of 12 parts, including the California Building Code (CBC) and electrical, mechanical, and plumbing codes. However, the most common use of “Title 24” refers to Part 6, the California Energy Code, which sets energy-efficiency standards for both residential and non-residential buildings throughout the state.
The Title 24 California Energy Code sets regulations for appliances, pools and spas, lighting, insulation, and roofing, as well as for “fenestration products,” which includes windows and exterior doors. Before a local building department issues a permit for new construction, remodels, or additions, they’ll check that the project’s Title 24 Energy Report fits the requirements. They might also perform Title 24 inspections throughout the build.
What is Title 24 for windows?
Title 24 windows have a big influence on whether a home will meet the overall energy-efficiency requirements. According to Title 24, a window is a vertical product made up of a frame and a sash with at least one piece of glazing, or glass. Under Title 24, California windows must meet standards for both U-factor and solar heat gain coefficient (SHGC). They must also be at least double-paned glass.
It’s important to note that there are 16 energy zones in California. While the requirements for Title 24 windows and doors are the same for each zone, there is no SHGC requirement in climate zones 1, 3, 5, 16.
Solar Heat Gain Coefficient
Solar heat gain coefficient (SHGC) is a number between zero and one that represents how much solar heat passes through the glass. Lower numbers are better: A number closer to 0 means that the window keeps out more heat, while a number closer to 1 means the window lets in most of the solar heat.
In climate zones 2, 4, and 6 through 15, the Title 24 requirement for windows is an SHGC of 0.23 or lower (closer to 0). SHGC is especially important in these hot climates, as a lower number means air conditioning won’t have to work as hard to cool the home (known as the “cooling load”). That’s also why there is no SHGC requirement in the cooler climate zones.
U-Factor Requirement
The U-factor measures how much heat can pass through the entire window assembly, not just the glass. It’s also the inverse of the SHCG: Essentially, SHGC measures how well the window keeps heat out, while U-factor measures how well the window keeps heat in. That makes it especially important for cooler climate zones. Like SHGC, a lower U-factor (closer to 0) is better.
The U-factor includes heat losses through the center of glass, at the metal spacers that separate the panes, through the frame, and through the mullions. CA Title 24 windows must have a U-factor of 0.30 or lower.
Replacement Windows
Title 24 requirements for windows apply to all new construction homes and additions that require permits – but what about if you’re just adding a few new windows or replacing existing windows? These projects are known as “alterations” under Title 24, and here are the rules: If you’re replacing more than a total of 75 square feet of windows, you’ll need to follow the above standards. For less than 75 square feet, replacement windows must have an SHGC of 0.35 or less and a U-factor of 0.40 or less.
Do aluminum windows meet Title 24?
The frame plays a big role in a window’s U-factor rating, and oftentimes, aluminum windows won’t meet the Title 24 requirements. As a metal, aluminum is typically not a good insulator and allows too much heat loss through the frame. However, you may be able to find some aluminum windows that meet Title 24.
At MILGARD, we use polyurethane thermal barriers in our aluminum windows to reduce the flow of heat. The operating style, number of glass panes, and the type of spacer, gas, and grid also affect a window’s energy efficiency.
For example, several of our aluminum picture windows are Title 24 compliant. For window replacements of less than 75 square feet, even more of our aluminum windows may be Title 24 compliant. You can always find all window specifications, including thermal charts, on our website.
What are Title 24 compliant patio doors?
Title 24 compliance also applies to certain exterior doors. But when does an exterior door need to meet the standards for SHGC and U-factor? According to the code, when a door is made up of more than 25% glass, it becomes “fenestration,” which must meet the standards.
Patio doors are almost entirely glass – even French doors and other styles with grids. Therefore, any project in California is going to need Title 24 compliant patio doors. The doors must follow the same requirements as Title 24 windows: an SHGC of 0.23 or lower and a U-factor of 0.30 or lower.
Tips for finding Title 24 compliant windows and patio doors
The easiest way to find Title 24 windows and patio doors is to use MILGARD’s Energy Calculator. You can simply check off “Qualifies for California Title 24” to see a complete list of all of our Title 24 compliant windows and doors. You can also search by frame material, operating style, and more.
The National Fenestration Rating Council (NFRC) independently tests windows and patio doors and publishes detailed information on SHGC, U-factor, and more. Title 24 energy calculations depend on the NFRC ratings to ensure compliance, so the NFRC Directory Search tool is also a good place to start your search for Title 24 windows.
To get closer to Title 24 compliant windows, check off the “ENERGY STAR products only” option in the NFRC directory. ENERGY STAR is a separate, national certification program. The ENERGY STAR certification criteria isn’t as strict as Title 24, so you’ll need to do more research into the exact specifications of the windows. Still, this is still a good way to narrow down your initial search.
Shop Milgard for the best Title 24 windows and patio doors
If you do use our Energy Calculator, you’ll quickly find that when you take into account options for operating styles, glass types, gas fills, and frame materials, we have thousands of options that are Title 24 compliant.
If you’re serious about finding the best Title 24 windows and doors, it’s time to contact one of our experts for a consultation. We’ll walk you through technical specs, Title 24 compliance, and more, so you can be confident your California projects sail through the permitting process.
