Dwight B. of Oregon writes in:
Hello, I need some information to fill out the Oregon tax credit for solar pool heaters. It is asking for an “estimated annual useful energy production of the solar pool heating system in kWh per year. Thank you, Dwight”
The form Dwight mentions in his request is part of the Application and Verification Form for the Oregon Residential Energy Tax Credit, currently available in the state of Oregon through the Oregon Department of Energy (ODOE). This tax credit provides a tax credit for solar water heating systems (including pool heating applications) based on annual estimated energy savings.
The credit is based on $0.15 per kWh of estimated savings, and is capped at a maximum of $1500 or 50% of the total system cost – whichever is less.
Though there are currently no federal tax incentives for solar pool heating, credits and rebates are sometimes offered by state and local municipalities. Such incentives can really sweeten the deal for pool owners looking to go solar by further reducing the already rapid payback period of a solar pool heater.
Back to Dwight’s system. After a brief phone call with Dwight to find out the size and quantity of his collectors (seven 4′ x 12′), as well as his expected swimming season length (5 months) it was an easy matter to determine the annual yield of his solar pool heater.
Though solar water heating system performance is generally measured in Btus (British thermal units), much like a natural gas heater, both the Solar Rating & Certification Corporation (SRCC) and the International Association of Plumbing & Mechanical Officials (IAPMO) list performance ratings in kWh, which is required by the application. In Dwight’s case, we used the SRCC performance matrix for Ecosun.
The following process is how we determined his system’s yield:
- Average seasonal pool heating conditions are best depicted by SRCC Category B, 1500 Btu/sq. ft. (4.7 kWh/m2/ day).
- At Category B 1500 (2.8 kWh/m2/ day), a 4’x12′ (1.22m x 3.66m = 4.47m2) collector will produce 12.5 kWh per collector per day.
Therefore, a 5-month (150 day) heating season would result in an estimated seasonal production capacity of:
12.5 kWh per collector/day x 7 collectors x 150 days = 13,125 kWh
Based on this figure of annual yield of 13, 125 kWh and a tax credit of $0.15 per kWh, Dwight’s system will meet and exceed the maximum tax credit of $1,500.
Thanks for writing in, Dwight!