It feels good to be ahead of the curve sometimes. About this time last year, I was slaving away painting my roof white – much to the bemusement of my Northern Virginia neighbors and friends. So I couldn’t help feeling just a little smug this morning as I read that US Secretary of Energy Steve Chu is also a great fan of roof-painting to combat global warming…


Perhaps the whitest roof in Northern Virginia

According to The Independent newspaper,

Steven Chu, the US Secretary of Energy and a Nobel prize-winning scientist, said yesterday that making roofs and pavements white or light-coloured would help to reduce global warming by both conserving energy and reflecting sunlight back into space. It would, he said, be the equivalent of taking all the cars in the world off the road for 11 years.

Speaking in London prior to a meeting of some of the world’s best minds on how to combat climate change, Dr Chu said the simple act of painting roofs white could have a dramatic impact on the amount of energy used to keep buildings comfortable, as well as directly offsetting global warming by increasing the reflectivity of the Earth.

A couple of years ago, we moved into a house with no loft space – just a few inches of paltry insulation between the standard-issue dark-shingled roof and our main living area.  And in the summer, things got hot.  Really hot.  The solution seemed obvious – paint the shingles white, to reflect the sunlight and prevent any unnecessary warming.

Now painting your roof is not something that East Coast folks seem to go in for, and it took a year to pluck up the courage and act on my convictions.  But come the warm weather last summer I decided that enough was enough.  So I purchased vast quantities of Hy-Tec Thermal Solutions Insul Cool-Coat white paint, power-washed the roof (an adventure in itself), and spent three back-breaking days painting the shingles white.

I’d like to report that, in a controlled comparison, the impact of the paint was immediate and stunning.  Unfortunately the AC unit packed in half way through the painting exercise so a strict A/B comparison was out of the question – just my luck!  Nevertheless, the qualitative and quite unscientific results of the new paint were pretty impressive – the upstairs rooms in the house underwent a figurative transformation from fiery furnace to cool cave!  More significantly, the temperature under the painted shingles was some 30 degrees Farenheit lower than that under the unpainted shingles on the garage under the mid-day sun – suggesting that an awful lot of the sun’s heat was no longer infiltrating the house.

The whole point of the exercise was to reflect as much of the sun’s heat as possible, rather than it being absorbed by the previously dark roof and subsequently having to be pumped out (at considerable expense) by the air conditioning.  The paint I used also acts as an insulator.  It’s crammed full of hollow microspheres that inhibit the flow of heat through it, as well as reflect back the sun’s light.   I think it worked – certainly the new AC system seems to be under less strain in the summer, and the house feels significantly more comfortable.  But by increasing the roof’s albedo, I was also able to do my (admittedly small) bit to counter global warming by reflecting away more of the sun’s energy.

It’s not an idea that has had much traction around here – yet.  I suspect the only way I’ve got away with it is by exuding an aura of eccentricity – at least the neighbors could whisper “well, he’s British you know…”  But now that Steve Chu has enlightened the world to the benefits of roof-painting, who knows where we’ll be in 12 month’s time – forget about going green, maybe the “white revolution” will come to McLean Virginia – and I will be able to proudly say I was there first!

Of course, regular roofs are probably trickier to paint than ours, which has a reasonably low pitch.  And I suspect not everyone will appreciate the aesthetic of white shingles or (shock horror) white painted slate.  But it has to be said, as a cheap and achievable solution to a significant problem, roof-painting has a lot to recommend it – a little bit of personal geoengineering to make the earth a better place!

It just took a savvy Nobel prize-winner to let the cat out of the bag!