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Solar planning, made clear

Washington solar savings calculator

Compare costs and savings with editable planning inputs. Use your own Washington utility tariff for a decision-ready estimate.

Prepared by Solar Panel CalculatorContent updated 2026-10-01Editorial standards
Use your quote; this default is an assumption.
Tariff & long-term assumptions
Share of generation used at home; include battery losses.
Use your utility tariff; zero is the conservative default.
Rooftop adds $0.55/Wh; plug-in cost is entered above.
Cost recurs at each interval within the 25-year model.

State rates and sun hours are illustrative defaults. Replace with your bill and a location-specific yield estimate. No homeowner §25D credit is assumed.

Your planning estimate

What could solar save?

Costs, tariffs and time all matter.

Your estimate
Enter your assumptions to see gross and net savings.

Washington: planning snapshot

These starting figures are illustrative inputs, not verified current Washington averages. Use your own bill and an address-specific production estimate before drawing a conclusion.

InputStarting valueInterpretation
Retail energy rate13.8¢/kWhReplace with your marginal energy charge.
Monthly bill$110Illustrative household example, before removing fixed fees.
Solar resource3.7 peak sun hours/dayApproximate input; does not model shade or seasonal weather.

A worked Washington savings example

Using a $110 monthly bill, $20 in fixed charges and a 13.8¢/kWh energy rate, the model sizes approximately 6.8 kW of panels. At 3.7 peak sun hours and an 86% performance factor, modeled first-year production is 7,898 kWh. An assumed $2.75/W cash price gives an upfront solar cost of about $18,700, before battery costs or incentives.

At 50% self-consumption and zero export compensation, year-one gross bill savings are approximately $545. If the export rate were equal to retail, the same production would be valued at about $1,090. These are tariff illustrations, not statements of the rules in Washington.

Export assumptionYear-one gross savingsWhat changes
No export payment$545Only the self-used half avoids energy purchases.
Export equals retail$1,090Exported output receives the same per-kWh value in this simplified example.

Production questions for a Washington roof

Roof-specific weather and exposure matter more than a broad regional label. Marine cloud, island conditions and latitude can produce substantially different output profiles. Compare the proposed installation with an address-specific yield model.

Request a monthly generation estimate and the roof assumptions behind it: panel orientation, tilt, shade, usable area and losses. The calculated capacity is a target derived from annual usage; a real design may be constrained by roof area, service capacity or interconnection rules.

Utility tariffs and incentives in Washington

Confirm your utility’s current tariff, whether exported energy is compensated, settlement frequency, credit expiry, minimum bills and any enrollment limit. For incentives, verify the current program with its administrator. Availability, funding and ownership conditions can change; this page does not claim a rebate is open without a verified program record.

Check DSIRE as a discovery tool, then read the responsible utility or program administrator’s documentation. Do not combine a quoted payback that already includes incentives with a second deduction for those same incentives.

Would a battery improve the numbers?

A battery may shift generation into household use or higher-priced hours. Compare the additional avoided charges with the installed storage cost, usable capacity and replacement schedule. In this tool, self-consumption is your estimated share after storage losses. Backup capability must be checked separately against the approved equipment and wiring.

A small plug-in example

An 800 W array at the 3.7-hour planning input and an 85% performance factor produces approximately 2.52 kWh on an average modeled day, or 918 kWh per year. At 75% self-use and no export compensation, that corresponds to about $95 in annual gross bill savings. Your actual output and allowed connection method may differ; use the readiness checklist before purchasing.

Federal homeowner tax treatment

The IRS states that the residential clean energy credit is not available for property placed in service after December 31, 2025. This calculator therefore applies no homeowner §25D credit. Third-party-owned projects use different business-credit rules; do not assume a lease passes a credit to you. Confirm eligibility and contract pricing separately.

Questions for Washington households

Is solar worth it in Washington?

It depends on the cash price, roof output, self-consumption and your actual utility tariff. In the worked example, valuing exports changes first-year gross savings from about $545 to $1,090; use your own inputs instead of treating either figure as a forecast.

Are the Washington figures official current averages?

No. They are clearly labeled illustrative inherited defaults. Their exact original reporting period was not established. Replace them with your bill and verified current sources.

Can I connect a balcony system in Washington?

The calculator is not a legal authorization. Check enacted state rules, current utility instructions, local electrical requirements and the full product configuration before connecting.

Can solar remove the fixed portion of my bill?

This model leaves fixed charges out of avoidable energy consumption. Confirm minimum bills and other tariff rules with your utility.

Sources and verification

Links provide primary references or verification tools. Linking a source does not mean every calculator default is reproduced from it. See our data limitations.

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