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Solar Space Heating
All homes use solar energy to meet some of their heating needs. Homes designed with lots of south facing windows, thermal storage (e.g., tile floors) and overhangs can easily reduce annual heating bills by 20 percent to 30 percent in Oregon with little additional expense.
 
Well-built passive solar homes offer:
  • Better temperature control
  • Bright day-lit spaces
  • Lower energy bills
 
Oregon provides a $1,500 tax credit for passive solar space heated homes. Each tax credit application is individually reviewed. Following are the key elements reviewed.  Contact the Oregon Department of Energy at (503) 378-4040 for additional information or by email at  energyweb.incoming@state.or.us.
 
Requirements 
1
Building layout must maximize passive solar gain (less used areas on north side, etc.)
2
At least half of the window area must be facing within 30 degrees of due south
3
South window area greater than 7 to 9 percent of total floor area
4
Average window U-factor not greater than 0.35 (area weighted) 
5
South window Solar Heat Gain Coefficient (SHGC) at least 0.55
6
Thermal storage (expressed in diurnal heat capacity) is equal to 30 times the area of south facing windows
7
Adequate overhangs
8
Less than 5 percent south shading from trees or buildings
9
North windows less than 2 percent of floor area
10
Skylights must be tinted and have an SHGC of no more than 0.30
11
Skylights no more than 1 percent of roof area
12
West window SHGC less than 0.40
13
The house has an operable window or skylight near the highest point in the roof or a whole house fan
Strongly Recommended
1
Home is performance tested by certified third party
2
Use thermal mass not thicker than 6 inches in southwestern and eastern Oregon and not thicker than 4 inches in northwestern Oregon
3
Non-occupied spaces (garage, utility room, etc.) located on north and west sides of home
4
High-efficiency furnace (90 percent+ efficiency)
5
Airlock main-entry doors
6
Use deciduous trees on west and east side of home to reduce summer cooling load
7
Keep use of skylights or “light-tubes” to a minimum
8
Install heat a recovery ventilation system
9
Use a moderately dark thermal storage color (brown, red, dark gray, green, dark tan . . .)
 

Favorite Files

Tax Credit-Certified Solar Technicians

Hiring Tips  

Basic Solar Information

Solar Tax Credits FAQ  

Sun Chart for PV and ST  




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Residential Solar Incentives 
 
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