Well, it’s February, so air conditioning costs aren’t exactly top-of-mind right at the moment. But considering approximately 7% of a restaurant’s energy costs are devoted to cooling, it’s not too soon to start planning how to reduce them.

One surprising way that you can save up to 15% on your cooling costs is to paint your roof white.

Yup. A white roof will help you reduce your air conditioning bills.

There’s a little more to it than that, though, so before you go grabbing the whitewash, here’s what you need to know.

What’s a cool roof?

A “cool roof” (which come in many colours and materials, although white is probably most common) reflects the heat of the sun rather than absorbing it. Think about it: if you wear a dark shirt on a sunny summer’s day, you’re going to feel hotter than if you wore a white shirt. Same principle.

By reflecting this heat back into the atmosphere, a cool roof stops heat from being transferred into your building—keeping your building cooler and reducing the need for Arctic-levels of air conditioning.

Benefits of a cool roof

It’s estimated that a cool roof can help you save up to 15% on your cooling costs in a year—and increases the comfort of your building.

What’s more, a reflective roof surface can help extend the life of your roof, since heat absorption is one of the primary factors that affects the durability of your roof.

Along with reducing cooling costs and extending the life of your roof, white or cool roofs have the potential to reduce greenhouse gases by cutting the amount of energy needed for air conditioning. In fact, it’s thought that if every roof in the world were painted white, the reduction in carbon emissions would be equivalent to taking 300 million cars off the road for 20 years. (That being said, there was a recent study that shows white roofs could potentially increase global warming—but it didn’t take the reduced need for air conditioning into account.)

Not only do white roofs make your building cooler, white roofs also help reduce urban heat island effect, which occurs when dark surfaces—asphalt roads and parking lots, as well as dark rooftops, raise the air temperature of an area 1 to 3 degrees higher than the area outside the heat island. One study showed that if urban heat islands were reduced, the Greater Toronto Area could save up to $11 million on energy costs.

Types of cool roofs

There are three types of cool roofs: ones that are made of an inherently reflective material, like white vinyl, ones that are coated with a solar reflective coating, and ones that have been planted with grass or moss (so-called “green roofs).

Green roofs are probably the most common types of cool roof in urban settings in Canada.

Installing a cool roof

Cool roofs are appropriate for both low- and steep-slope roofs. Of course, if you’re renting your space, you’ll have to work things out with your landlord (and for some tips on doing that, check out our post on how to talk to your landlord about energy efficiency).

If you live in an area with particularly cold winters, you may find the benefits of all that heat reflection results in an increased need for heating—so the wisdom of installing a cool roof depends on where you live. Take a look at this list of calculators to help you figure out whether a cool roof can work for you.

If you’re interested in more info about installing a cool roof, watch this video from the US Department of Energy. Then go talk to your roofer.

Image credit: Walmart