| Peak sun hours per day | 3.4 – 4.2 |
|---|---|
| Annual kWh per kW installed | 950 – 1,250 |
| Typical system size | 8.5 – 11 kW |
| Electricity rates | Below the national average |
| Export credit regime | Retail-rate net metering |
How Washington credits the power you export
Exported power is credited at or near the retail rate, so a kilowatt-hour sent to the grid offsets a kilowatt-hour drawn from it. This is the most favourable arrangement for solar, and it makes the economics mostly a question of system size versus consumption rather than of timing.
Because export credit tracks the retail rate, when you export matters much less here than it does under a net-billing regime. Batteries are a resilience purchase in this environment more than an economic one.
Which specific tariff applies to you is a question for your utility, not for Washington as a whole — several utilities operate in most states and their terms differ. Check the current rules before you sign anything.
The general mechanics are in net metering explained; this is how they land in Washington.
What a system costs here
Washington pricing sits broadly within the national band of $2.50–$3.50 per watt before incentives, so a typical 8.5 – 11 kW system lands somewhere around $21,000–$39,000 before credits. Local labour rates, permitting fees and whether you need an electrical panel upgrade move that more than the panel brand does. Full breakdown in what solar panels cost.
Incentives that stack in Washington
| Layer | What it does |
|---|---|
| Federal clean energy credit | A federal credit against the cost of a residential system. Federal incentive law changed in 2025, so confirm the current rate and eligibility before you count on it. |
| Export credit | Retail-rate net metering — retail net metering is what Washington generally applies, subject to your specific utility's tariff. |
| State and local layers | Property-tax and sales-tax exemptions, utility rebates and certificate markets exist in many states and change often. DSIRE lists what is live where you are. |
When solar is a poor fit in Washington
- A roof with less than about ten years of life left — replacing it later means paying to remove and reinstall the array.
- Heavy shade from trees or neighbouring buildings for much of the day. Micro-inverters help at the margin; they do not manufacture sunlight.
- Electricity is cheap in Washington, so a small bill leaves little to offset. Under roughly $80 a month, the payback usually stops making sense.
- North-facing-only roof planes. At this latitude the production penalty is large enough to change the answer.
- Planning to move within about five years. You will likely recover some of it in the sale price, but not reliably all of it.
The universal disqualifiers apply here too — renting, a roof near end of life, or moving within a few years. See roof age and solar and what happens when you sell.
Washington solar questions
Is solar worth it in Washington?
It depends on three things: what you pay per kilowatt-hour, what your utility credits you for exported power, and how much unshaded roof you have. Washington runs retail net metering and residential rates land around 11–14¢ per kWh, so the honest answer is that it works well for some homes here and poorly for others. The quickest test is your own bill: the larger it is, the more there is to offset.
How many solar panels does a house in Washington need?
A typical household using about 10,500 kWh a year needs roughly 8.5 to 11 kW here, which is about 21 to 28 modern 400 W panels. Your own consumption matters far more than any state average — pull twelve months of bills before sizing anything.
How much power does solar produce in Washington?
Plan on roughly 950–1,250 kWh per year for every kilowatt installed, based on 3.4–4.2 peak sun hours a day and a normal system derate. A 8.5 kW system therefore produces somewhere near 80,758.5 kWh a year — well above that in June, well below it in December.
What does Washington pay for exported solar power?
Retail-rate net metering. The exact credit depends on your utility and your tariff. Export rules are set by commissions and do change, so confirm the current terms rather than relying on any published summary, including this one.
Do solar panels work in Washington winters?
Yes, at reduced output. Panels are more efficient when cold; the losses come from shorter days and lower sun angles, not from temperature. Expect production to swing substantially between summer and winter, which is what annual figures are for.
General information for Washington homeowners, not financial, tax or engineering advice. Figures are planning ranges; your own quote depends on your roof, your consumption and your utility.