Solar Power Rocks logo

Solar Power Rocks - Clear info on home solar power rebates, tax credits, and other benefits

Get solar installed for $0 down in Washington!

Get quotes from trusted local installers

Privacy Assurance - We will not sell or otherwise transmit your personal information to others without your permission.

Washington State Solar Incentives—Updated!

Contrary to what many people think, Washington state is not a perennial rainscape. In fact, More than half of the state is arid sagebrush steppe land, and even the emerald city of Seattle enjoys almost 70% as many sun-hours as L.A. annually. Summer days throughout the evergreen state are commonly clear, and last longer than anywhere else in the lower 48. Washington voters support sustainable energy policy, and legislation is a testament to that fact.

We’ve updated the Washington State Solar Incentives page today, check it out! For teasers though, look at the negative cost of a 5kW system:

Sample 5kW home solar electricity system cost — Seattle

  1. Cost before incentives: $35,000 (5,000Watts*$7/W)
  2. 30% Federal Tax Credit: Subtract $10,500
  3. Estimated annual production ±5,500kWh*: subtract between $825 and $2,970
  4. Avoided Energy Costs: subtract about $440 (cost of electricity increases 5.5%/yr)
  5. Years to payback: as fast as 7 years!

Estimated Net Cost: between $21,088 and $23,233

Estimated Net Cost in 2020:¡-$12,437!**

*in most of Washington, a 5kW pv system will produce much more than 5,500kWh of electricity a year. Ask your local installer for more details.

**that’s right. A negative cost. That is the same thing as a payment. In this scenario, the system has paid you to the tune of $12,437.00!!! A 35% ROI! We kid you not. Ask your local installer for a payback estimate!

Last modified: July 24, 2018

How much can you save with a solar roof?

Profit from your roof space: find local deals on solar, eliminate your power bill, and join the solar revolution.

See my savings!

Leave a Reply

4 Comment threads
0 Thread replies
Most reacted comment
Hottest comment thread
2 Comment authors
AnerSam Harriman Recent comment authors
newest oldest most voted
Notify of
Sam Harriman
Sam Harriman


5,000W for 1 hour is equal to 5kWh, not 5,000.

Sam Harriman
Sam Harriman


Thanks for the comment!
1) 5,000 Watts is the rated generating *Capacity* in *power*. 5,500kWh is the estimated annual *output* in *energy*.
Quick example—you need 5,000W of generating capacity to *power* 50 100W light bulbs. If you are powering all 50 of those same bulbs for 1 hour you consume 5,000kWh of *energy*.
It’s confusing, I know. For more information look for Dave’s post about the difference between a Kilowatt and a Kilowatt-hour.

2) Yes, that is right, the Washington State production incentive pays system owners for *all* of the energy they generate—whether they use it or not.

Hope this helps. ¡Have a Happy 4th!


BOG I am a little puzzled… 1. How can a 5KW system produce MUCH MORE than 5,000 KHW?? That is what the system produces based on the specific, rated KW production of each of the panels – therefore, that is what you get… 2. I am also puzzled re: WA Incentive. It sounds like they pay you .15 per KWH produced regardless of whether you use it (generating additional savings) OR sell it back to the grid. This, as opposed to simply .15 for that which is sold back to the grid. Am I missing something -basically it is doubling… Read more »

Sam Harriman

Solar Power Rocks is a Wave Solar company

Wave Solar Logo