Passive Solar: Is Passive Lunar the Next Big Thing?

Daniel Chang emailed me a few days ago with some cynical observations about the state of passive solar in Austin and in the country today. “Maybe passive lunar contemplation will lead to something,” he says.

As we all know, active solar and solar panels get all the hype while passive solar design is often invisible to the untrained eye. To most people, “solar energy” is active solar. But passive solar is still a reality, just like the thermal properties of stone, earth, and wood are an enduring reality.

A quick survey of information about passive solar shows that, although architects and builders in parts of the country are using passive solar concepts, there’s no discernable trend toward increased use of passive strategies. So although passive solar is effectively free (can you imagine a national TV campaign for free passive solar?!?) there’s still plenty of room for improvement — and for increased energy and utility bill savings. For a lot of homeowners and commercial property managers, this is money on the table just waiting to be taken, but these savings have to be realized well before the construction stage.

Our key discovery was a report entitled Energy Policy by Kelly Kruzner, Kristin Cox, Brian Machmer, and Leidy Klotz. In it, the authors performed a satellite image inventory of 1000 homes across the country and evaluated the homes for their orientation to prevailing sun, roof color, and sun/shade exposure. They found that home orientation in some parts of the country is trending toward conforming with passive solar strategy — but at the same time roof color in many areas of the country is counter to passive principles. And as mentioned earlier, there’s no trend overall toward better passive solar design.

Here’s hoping passive solar becomes more well-known. There’s no reason it shouldn’t be.

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