This could be “a thermostat for the sun.”
Back in 2011 at Greenbuild, I was so impressed with electrochromic glass that I gave it my Best of Show prize. At Greenbuild 2019 there is a new glass that changes tint on demand called Halio. It’s faster than any other window, going from 99.5 percent black to clear in three minutes.
© Halio Glass
It works by sandwiching a layer of some form of ionic material (not liquid crystals) that change their alignment as you change the electricity between the anode and the cathode. But it only needs power to change; once you darken or lighten it, no power is needed to maintain it.
They developed the product for commercial uses, but I keep looking at this stuff and wondering why it isn’t used in Passive House designs, where you want solar gain when it’s cold, but want to block it when it’s hot.
I noted 8 years ago that in Passive House design,
Dark Halio Glass/ Lloyd Alter/CC BY 2.0
I called electrochromic glass “a game-changer. It’s not just about using more glass, but may be about completely rethinking the way we use glass in buildings, now that the solar furnace is almost as controllable as the gas or electric one.”
I noted at the time that “I left the booth in a bit of a daze, thinking about its possibilities as a thermostat for the sun.” Perhaps I get too excited. But it seems like such a good idea.
