How a “cool roof” can bring down the temps by as much as 50 degrees.
From planting leafy trees to provide shade around your home to regularly cleaning your air filters to help them operate more efficiently, there are several tips and tricks to help you cool your home that don’t involve cranking up your AC and letting it run all the way through early fall—increasing your energy bill, carbon footprint, and the chance of a power outage.
The latest idea making the rounds? Painting your roof white. But does it really cut down on your energy costs during heat waves?
Location Matters
If you’re custom-building a home or replacing a roof, there are white and light-coloured shingles that exist, but they tend to be most popular in hot climates where homeowners will benefit the most from energy savings. Those in colder climates may actually prefer black and grey roofing shingles because they can absorb solar radiation, helping to warm the roof and reduce the demand for heating during cold months.
If reducing your energy bills are your main objective, and you live in an area that gets blustery winters, a cool roof could actually increase your heating costs and cost you more on an annual basis.
Say N.O. to D.I.Y.
If you do decide a white roof is the way to go, painting it is a job best left to the professionals.
Painting your roof isn’t a one-and-done project, though. In order to maintain reflectivity, paint may need reapplication every three to five years, depending on climate and sun exposure.
Consider the Raw Materials
Some roofs will be easier to paint than others. Smooth asphalt shingles tend to hold paint better than textured wood shakes, which require more prep and primer.
They can be painted, but any rust or flaking paint should be removed. Using a wire brush or sandpaper, and a coat of metal primer applied before painting.
Slate and clay tiles are popular choices for roofs due to their durability and aesthetic appeal, but painting them may be more trouble than it’s worth. They are porous, which means they absorb moisture, and this can cause paint to peel or crack over time.
The bottom line?
Painting a roof white does keep a home significantly cooler. Whether it makes sense for you depends on where you live and what your roof is made of already.