Cool Roofs Are Now a Requirement in Altadena

by Val Zavala

If you are a homeowner in Altadena and need to replace your roof you will have to use “cool roof” shingles. L.A. County passed a cool roof ordinance in 2018 following similar action by the City of Los Angeles, Pasadena and Santa Monica. The cool roof requirement also applies to new construction or if you are replacing more than half of your existing roof. (Tile roofs already reflect heat and are not impacted by the ordinance.)

What is a “Cool Roof”?

A cool roof is made of shingles that contain a material that reflects the sun’s energy back into the atmosphere. Cool roofs absorb less heat and keep houses cooler. On a hot day the surface of a cool roof can be up to 50 degrees cooler than a traditional roof. Cool roofs will also help keep the outside ambient temperatures cooler.

Benefits of a Cool Roof

Not only will a cool roof keep you house cooler, it will reduce air conditioning use and lower electric bills. It will also ease demand on the electrical grid during heat waves.

How much do homeowners save in electric bills?

Each home is unique, but in general cool roofs will save an average of 7-15%, and up to 20%, on cooling costs.

How much do they cost?

There is no difference in the cost of cool roofs compared to conventional roofs. In fact, over time they are less expensive because they have a longer life than conventional roofs.

Aren’t “cool roofs” white?

No longer. Cool roofs come in all the traditional shades of grey, brown, slate and beige. The lighter shades are slightly more reflective, but they all meet the new standards and will keep your home cooler.

Are there any exceptions to the cool roof requirement?

Yes. Tile roofs are exempt because they already act as cool roofs. Also, if your home is in a historic district it may be exempt. Contractors and architects can look into possible exemptions.

Why are cool roofs important?

Altadena is in a “heat island”. Usually “heat islands” develop over dense urban areas where development and few trees create and retain hotter temperatures. In Altadena’s case we are not densely developed and we have a lot of trees. However, we are nestled up against the San Gabriel Mountains. Heat generated by downtown and other urban centers is blown toward the mountains. The mountains block the heat which settles in the foothill communities including Altadena.

A UCLA study predicts that by 2050 LA County will experience three to four times as many very hot days as we do now. How hot is “very hot”? 95 degrees or more. In short global warming is happening. Cool roofs are one step we can take to mitigate the impact. So anything we can do to keep our homes and community cooler is important.

Where can I learn more?

Watch the informative webinar by Altadena Heritage which features two experts and a homeowner who installed a cool roof.