Solar savings calculator
Solar Savings Calculator
Estimate annual solar savings and simple payback before talking to installers.
Use this page when the main question is annual bill savings and how retail rates, export value, and solar production interact.
Estimate preview
Panels, cost, savings
No email required
Estimate solar savings
Enter monthly kWh or electric bill. The calculator uses state-level assumptions and shows the math behind the result.
Your estimate
Example resultYou likely need 18-22 panels
Estimated system size: 7.8 kW. This is an estimate, not an installer quote.
Confidence
Medium
Planning estimate only — not an installer quote, engineering design, or tax advice.
Payback uses gross system cost before verified incentives, financing fees, batteries, and roof work.
- Estimated system size
- 7.8 kW
- Sized for your target offset and system loss assumption.
- Likely panel count
- 18-22
- Centered around 20 panels at 400W equivalent.
- Roof space
- 483 sq ft
- Includes a spacing factor, not a final layout plan.
- Annual production
- 10,800 kWh
- Modeled first-year output at the selected offset; not a production guarantee.
- Gross cost
- $18,445 - $23,939
- Before verified incentives, financing, or battery costs.
- Gross cost per watt
- $2.35 - $3.05
- Before incentives. Useful for comparing installer quotes.
- Annual savings
- $2,693
- Based on state residential rate and self-consumption assumption.
- Payback
- 6.8 years - 8.9 years
- Simple gross-cost payback estimate.
Annual usage: 10,800 kWh
Annual production target: 10,800 kWh
State rate: 35.25 cents/kWh
Export assumption: Partial export credit
Direct solar use: 5,940 kWh
Modeled exports: 4,860 kWh
Panel count view
18-22 panels
Estimate shape
Production, savings, and payback
Privacy note: the printable report link stores estimate inputs in the URL, including ZIP and usage or bill values. Keep it private if those details are sensitive.
Local scenarios
Save estimates on this device
Compare a few assumptions without creating an account.
Saved scenarios stay in this browser only and may include ZIP, bill, and usage inputs. SolarCalcNow does not sync them or send those values to analytics.
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Assumptions behind this estimate
- California state-level electricity rate and solar production defaults are used.
- 100% bill offset target.
- 400W solar panels.
- 14% system loss assumption.
- Roof area uses about 21 sq ft per panel plus spacing factor.
- Gross cost range excludes verified incentives, financing, batteries, roof work, and panel upgrades.
- 55% of annual solar production is modeled as directly used before export.
- Export value assumption: Partial export credit.
- Savings are energy-only and exclude fixed charges, minimum bills, demand charges, and time-of-use detail.
- You provided monthly kWh usage.
- State production defaults are used for this estimate.
Confidence drivers
- Overall confidence: Medium.
- You provided monthly kWh usage.
- State production defaults are used for this estimate.
Expected production: 10,800 kWh
System loss: 14%
Export value: Partial export credit
Direct solar use: 5,940 kWh
Modeled exports: 4,860 kWh
State production default: 1,600 kWh/kW/year
SolarCalcNow provides planning estimates only. Results are not installer quotes, engineering designs, tax advice, financing recommendations, or utility interconnection approval.
Optional next step
Want installer quotes based on this estimate?
Your estimate stays visible. This form is optional and uses explicit consent.
Installer quote matching is not active yet. You can still calculate, save, and print your estimate before contacting installers directly.
SolarCalcNow provides planning estimates only. Results are not installer quotes, engineering designs, tax advice, financing recommendations, or utility interconnection approval.
Real baseline
What the calculator returns for 900 kWh/month
Savings and payback rows use gross installed cost and state export-credit assumptions — not loan, lease, PPA, or net-after-incentive pricing.
| State | System | Panels | Gross cost | Payback |
|---|---|---|---|---|
| California | 7.8 kW | 18-22 | $18,445-$23,939 | 6.8 years-8.9 years |
| Texas | 8.4 kW | 19-23 | $19,674-$25,953 | 15.2 years-20.0 years |
| Massachusetts | 10.0 kW | 24-28 | $27,628-$36,670 | 12.3 years-16.3 years |
Savings are driven by the electricity you avoid buying from the grid and the value of any exported solar energy. The MVP uses a conservative export assumption and state residential rates.
Actual savings depend on your utility rate plan, net metering or net billing rules, system design, seasonal usage, and future rate changes.
Compare planning presets
Same calculator engine with a different starting assumption. Useful before comparing installer quotes.
Monthly usage presets
Panel wattage presets
State calculators
Start with local assumptions
FAQ
Common solar calculator questions
Does this estimate future utility rate increases?
No. It uses current state-level rate assumptions. Future rate escalation can be added later as an advanced setting.
Can batteries improve savings?
Sometimes, especially with time-of-use rates or backup needs, but batteries may not improve simple payback.
Why do export credits affect annual savings?
If your utility pays less for exported solar than you pay for imported electricity, offsetting usage saves more than exporting excess production.
What to do next
After calculating, save the estimate assumptions, check incentive status, and compare installer quotes against the same baseline.