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Passive Solar
Passive solar space heating is a home design method that takes advantage of sunshine to heat a home. Heat from the sun enters a home through south-facing windows, and warms materials that store heat, such as concrete, stone, and tile. The heat radiates into the home throughout the day and night.

Certain passive solar space heating systems installed in your Oregon home may be eligible for a Residential Energy Tax Credit.

RETC Qualifications

​Passive solar space heating in a home must meet certain qualifications to earn a Residential Energy Tax Credit​ up to $1,500, depending on how much energy is saved. See th​e RETC Rate Chart​ for more information.

Complete qualifications and instructions are outlined in the RETC Application. 

Passive solar space heating systems must:

  • ​​Produce energy savings equal to at least 20 percent of the annual energy used for heating in your home.
  • Be installed in your Oregon home, which can be new construction or a renovation.
  • Meet certain design standards, outlined in the RETC Rules.

RETC Program Sunset

The RETC program ended on December 31, 2017. 

To qualify for a 2017 tax credit:
  • RETC devices must have been purchased by December 31, 2017;
  • Devices must be operational by April 1, 2018; and
  • ODOE must receive your application no later than June 1, 2018.
If you plan to transfer your tax credit, ODOE must receive the pass-through application on or before June 1, 2018. Please review the RETC Administrative Rules for more information about program eligibility and requirements.​​


A qualified engineer or home designer can model your estimated savings using an energy analysis software, or by meeting specific passive solar design requirements.

Ask your installing technician to complete the technical section, Sun Chart Worksheet, and Thermal Storage Worksheet in the RETC application.

Complete the rest of the application, listing any other incentives you are receiving. Send it to the Oregon Department of Energy with a copy of your receipt listing the date and the price you paid.​ Include back-up documentation such as photos, home plans, or other paperwork showing your passive system. 


Other federal, local, or utility programs may also offer incentives .


2016/17 Passive Solar Heating RETC Application
2017 RETC Rate Chart ​​​​​​​​​​​​​

2016 RETC Rate Chart ​​​​​​​​​

​​​​​​​​​​​ RETC Administrative Rules​​​​​​

​​​​​​​​​​ Incentives Ending in 2017 ​​​​​
​Contact the RETC Team: