[Greenbuilding] passive solar homes - floors

[Nick Pine]

susannah writes:

> I have an attatched sunspace, and use a fan to bring the warm air in. 

That's a lot more efficient than direct gain, if the sunspace has no thermal mass, so it can get cold at night. The fan might be in series with a room temp heating thermostat and a sunspace cooling thermostat, with a damper that closes when it isn't running.

> I'm in Eugene, OR.  I could imagine a zero-energy-for-heaters house here...

That's almost as difficult as Portland. Here's a list of NREL OR cities in order of "sun/DD," a metric from PE Norman Saunders:

Portland    470  40.2  16.9
Eugine      460  41.1  17.1                  
Pendleton   580  34.3  17.2
Salem       490  40.0  17.5
Medford     550  37.8  18.2
Burns       840  25.1  19.6
Astoria     520  50.9  20.3
Redmond     850  31.8  23.5
North Bend  740  46.1  33.8, vs

Albuquerque 1610 35.3  54.2
             |    |     |
             |    |      -- sun/(68-Ta)
             |     -- Ta = average December temp
              -- sun = Btu/ft^2-day on south wall
Nick