Question

I am building my home, and I wish to have solar installed now or in the future. What does solar orientation mean?

Asked by Patty Smith
Augusta, MI

I understand the panels need to be able to face the sun, but what is passive solar?

Answer

Florian Speier

Answered by Florian Speier

San Francisco, CA

Zeitgeist Sustainable Residential Design

April 11, 2011

When we talk about solar power in regards to buildings, this can mean two very different approaches.

Any building can use either one or both:

Active Solar

This is what nearly all the advertisement is about -- solar panels, typically installed on the roof, that either create electricity or hot water.

The electricity is typically fed into the network of the total utility, which in turn gives you credit to take that amount of power out of its network when you need it.

Solar hot water panels, either plate collectors or the more efficient evacuated tube collectors, produce hot water that you can use to shower, wash your dishes, etc., as well as heat your house with hydronic radiant heating.

Passive Solar

Passive solar, of which solar orientation is a part, is the art of building a house so that its energy use is minimized, utilizing its exposure to the sun.

  • In a heating climate, this would mean southern exposure with lots of south-facing windows, but little or no east, west, or north-facing windows.
  • This will make the sun heat the house.
  • Balanced with the right amount of insulation and thermal mass inside the house (such as concrete floors, stone walls, etc.), this can eliminate the need for any heating in most climates, as long as there are no extended periods when the sky is overcast.

I have visited beautiful houses in the Swiss Alps when there were three feet of snow outside that were perfectly warm inside. Temperature graphs that have been recorded for many years show that the best of these houses never get cooler than 65 degrees inside and never warmer than 75 -- all without any heating, cooling, or even active solar technology.

For a longer discussion of the different approaches to passive solar house design, please see my other articles on GreenHomeGuide here.

 

For more information:

Read "Which way should we orient our green home in Boca Raton, FL?" a Q&A answered by Randy Potter.

Tagged In: passive solar

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