Color-changing roof tiles absorb heat in winter, reflect it in summer
phys.org
(PhysOrg.com) -- Anyone who has ever stepped barefoot onto blacktop pavement on a hot sunny day knows the phenomenon very well: Black surfaces absorb the sun's heat very efficiently, producing a toe-scorching surface. In the wintertime, that can be a good thing: A dark roof heats up in the sun and helps reduce your heating bill. But in summertime, it's definitely a bad thing: Your house gets even hotter, and your air conditioning has to work harder. In most places, the summertime penalty is greater than the wintertime gain, it turns out, so that's why many people, including U.S. Secretary of Energy Steven Chu, strongly advocate switching to white roofs.

The article is from 2009. It presents new roof tiles that become black in winter in order absorb heat from the sun, and white in summer to reflect it. I still can’t buy these as far as I’m aware. What happened to that? They do write

Savings from the black state in winter have yet to be quantified.

So maybe it turned out that it wasn’t worth it compared to tiles that are white year round?

  • DemocratPostingSucks@lemm.eeEnglish
    2·
    4 months ago

    Maybe this question didn’t have the right answer:

    The biggest remaining question is over durability, and answering it will require spending some time to do accelerated testing by running the material through repeated hot-cold cycles.