We all know it gets hot here, especially in the summer, and that the sun blazing on your roof is a major cause of your house feeling so hot.
There’s two main ways to stop this – making your roof more reflective by covering it in light-coloured paint or covering it in solar panels.
Solar panels work in three ways
Solar panels form a barrier between your roof and the sun. Of course, the panels themselves become hot, but this heat doesn’t make it to your roof because of the air gap.
Some of the heat that the panels absorb gets turned into electricity, which actually stops them from getting as hot as you might imagine.
They also help to power your aircon by doing what they’re designed to do – generate electricity.
What about reflective paint, though?
Yes, a light-coloured roof will reflect a lot of sunlight back out into space, leaving it – and in turn your house – a bit cooler. However, it’s not as effective as you might think, reducing the cost of running the aircon by just 15%. Conversely, having a reflective roof might bump up your heating costs in winter, so there’s no real benefit here.
Plus that, reflective paint isn’t cheap
On average, an Australian house has 160sqm of roof area, and if the reflective paint costs around $15 per square metre then you’re looking at around $2,400. You’ll be spending a lot of money to save less than $100 a year, once the sums are broken down.
It’s just not worth it
The benefits of a solar array
With the physical barrier of a solar array in place, you’ll be knocking out at least 90% of the sun’s energy before it gets transferred through the roof as unwanted heat.
Of course, a solar array will probably not cover all of the roof space. On average, a solar array will cover around 25% of available roof area, reducing aircon costs by around $20-30 a year. However…
Your solar array will run your aircon for you – for free!
It could also provide you with a small additional income, rather than just lying in an inert layer like paint. An inert layer that cost $2,400 and will take more than 20 years to pay for itself. Your solar array, on the other hand, will pay for itself in five or six years and still go on earning for you for another 20 years!
So, to sum up
If you’re in a very hot region, every little helps, so get your roof painted white when you have it replaced or repaired. However, your main source of savings on aircon, as well as an additional trickle income, is definitely solar panels.