If you have been in the home purchasing, selling or remodeling process in Northern California recently, you may have heard about Title 24 energy reports required by building departments. What most homeowners do not know is that all California residential homes are required to comply with these energy standards and that Title 24 measures the overall energy efficiency of your home. Now when it comes down to the nitty-gritty details, that can be a very broad umbrella of compliance and thus Title 24 energy codes can apply to just about any project, from installing new light fixtures or appliances to, replacing or installing new windows and/or doors.
As of July 1st 2014, Title 24 compliance is required for all new California residential homes and remodels, without exceptions (unless you pay much more for an entire "envelope upgrade"). If you choose to install products that are not compliant, you will fail your building inspection. Moreover, increased energy efficiency reduces homeowner energy costs, increases reliability and availability of electricity, improves building occupant comfort and reduces the overall impact to the environment. These standards are important for introducing sustainable technologies for California’s energy future (and to pass building inspection) thus it is within the best interest of every homeowner to comply with these standards.
So how does this apply to your window or door purchase?
The most significant changes in the 2013 Building Energy Efficiency Standards affecting residential buildings include the new requirements for high performance fenestration products. Title 24 requires windows and doors with a U-Factor of 0.32 and a SHGC (Solar Heat Gain Coefficient) of 0.25 in most climate zones (Section 150.1(c)3A). If you are located on the San Francisco peninsula, you are most likely in what is called "Coastal Zone 3". Luckily for Bay Area homeowners, that translates to a much milder climate than the majority of the US (and therefore less stringent/aggressive energy efficiency requirements/needs), but hey, extra energy efficiency and reducing costs can NEVER be a bad thing.
Terminology
What is a U-Factor? The U-factor measures how well a fenestration product prevents heat from escaping a home or building. U-factor ratings for windows generally fall between 0.15 and 1.20. The lower the U-factor is, the better a product is at keeping heat inside the building, thus is a better insulator.
Solar Heat Gain Coefficients? That measures the fraction of solar energy transmitted and tells you how well the product blocks heat coming into the house caused by sunlight. SHGC is measured on a scale of 0 to 1; values typically range from 0.25 to 0.80. The lower the SHGC, the more a product is blocking solar heat gain. Blocking solar heat gain is particularly important during the summer season in warmer climates. By contrast, people in cooler climates may want solar heat gain during the cold winter months to lessen the cost of heating the home.
In order to comply with Title 24 regulations, most fenestration manufactures have pre-established U-Factors and SHGC for their product lines. U-factors and SHGCs can and often vary by manufacturers and material however, by adding thicker double panes and low E glass, homeowners can have more flexibility in design to meet those minimum requirements.
Important to note here: most aluminum window and patio door products on the market do not comply with Title 24 standards because as aluminum is a metal, it does not make a particularly good insulator. One exception to this is LaCantina Doors, a contemporary residential and commercial large door brand: learn more here). If having an aluminum finish is a must for you, try an aluminum clad line such as Andersen E series. Standards are subject to change so be sure you know the specific requirements and regulations for your city. You can always get the latest information on Title 24 for your area by contacting your cities local building department.
However, the building department doesn't always have the final say for fenestration products. Also, Homeowner Associations are notorious for having stringent regulations and compliance standards for the appearance of windows that can often differ from your cities Building Department. If you have one, be sure to contact your local HOA branch for site specific regulations.
Sources:
http://www.nfrc.org/windowratings/Energy-ratings.html#sthash.4zE5bzEg.dpuf
http://www.title24express.com/what-is-title-24/
http://www.energy.ca.gov/title24/