Home energy costs rise at an average of about 7% a year, which is well above the rate of inflation. It’s also well above the average rate of raises employees get each year, which means you’ll be spending more on your house than will be going into your wallet. While houses almost always appreciate in value the longer you hold onto them, we’ve seen with the recent housing crash that that’s not always the case. However, there is one way you can lower your home energy costs more than the rate of energy rises each year, and it’s a way that’s got some serious credibility to it: a Nobel Prize-winning scientist has backed it up as working. Curious? Read on to learn more.
The Science Behind Home Energy
Getting into the nitty-gritty of how heating and cooling your home works is extremely complicated, especially because not every single home uses the same approach. So instead of writing pages and pages of academic-level words about thermodynamics, we’ve found a way that’s simpler and makes a lot more sense:
Dark surfaces retain a lot of the heat and energy that hits it from the sun’s rays.Light surfaces reflect much of the heat and energy that the sun shines down on it.
There are other factors at play here and we’ll get into a few of them later on, but that’s essentially it: dark equals hot, and light equals cool.
How This Basic Science is Applied to Houses
Close your eyes and think of what houses look like in typically hot countries, like Spain, Morocco and Malta. In your mind, do you see dark-colored brick houses, or pastel-hued clay-roofed houses? The answer is almost always the latter, as homeowners have, for centuries and centuries, needed a natural way to cool their homes before air-conditioning came along. They discovered that using lighter colors on their roofs was the most efficient way at keeping the interiors cool, for the very reason we listed above: the lighter the color of the roof, the likelier it was to reflect a greater amount of heat and energy back into the atmosphere.
Enter Steven Chu, our Nobel Prize-winning scientist who also doubles as the US Secretary of Energy, and his work from a few years ago. Chu talked at a conference about how having white roofs could lower a homeowner’s energy costs by 10-15% because of its increased reflectivity. This is in contrast to darker surfaces, where the sun’s light is largely absorbed. Another neat side effect is that when more sunlight gets reflected back into the atmosphere, it doesn’t insulate or barricade a layer in the atmosphere that acts as a trap for infrared light; more infrared radiation needs to be bounced back than already is, but is trapped because of greenhouses gases. Hence, lighter roofs, in theory, equal less electricity needed to cool the insides of homes, and lower energy bills. And will less reliance on the power grid, that’s even less “gunk” going into the atmosphere and contributing to climate change.
What Critics of White Roofs Have to Say
First and foremost, having a white roof isn’t equally beneficial to all homeowners. If you live in a very sunny, warm state, like Florida or Nevada, a white roof would be perfect for you. The mercury rarely drops below 40ish in the coldest months, meaning a lot of sun and heat are present year round. For homeowners in cooler states with definite winter seasons, like Minnesota or Wisconsin, we get into a bit of a gray zone. They do get warm summers, but their cold months, which can last for about six months, may negate any beneficial effects of a white roof. Some critics even say that with the amount of sun and heat the white roof would reflect in the winter would leave the home so much cooler, the summer savings would be negated by increased heating in the winter.
Another concern is white roofs’ efficacy in controlling global warming. A paper written by Stanford researchers found that with the increased sun reflection back into the atmosphere, cloud thickness was decreased, which meant that even more sunlight was able to reach the ground. In turn, this increase in sun and heat bounced back into the atmosphere, contributing more greatly to global warming (remember the insulation barrier we talked about before) than taking away from it by absorbing more emissions.
So, is it Worth Having a White Roof?
We’re going to go with a solid yes on this one, as most of the evidence and literature we’ve read points in that direction. To our eyes, having a white roof does far more better things for both your energy bill and the environment than it seems to otherwise, and we’re big fans of this concept.