Every solar buyer asks the same question first: "How much money will I actually save?"
The answer depends on three things — your state's electricity rate, your solar system size, and how much of your production you use directly vs. export to the grid. Our free Solar Panel Savings Calculator calculates all three instantly.
This guide explains how the calculator works, what the results mean, and how to use them to evaluate installer quotes.
Use the Calculator Now
Before diving into the methodology, try the calculator with your own numbers:
→ Solar Panel Savings Calculator: Get Your Personalized Estimate
Input your state and monthly electricity bill and you'll get:
- Year 1 monthly savings
- 25-year cumulative savings vs. staying on the grid
- Recommended system size and cost
- Your simple payback period
The calculator uses 2026 electricity rates and solar irradiance data for all 50 states.
How Solar Savings Work
Solar saves you money in two ways:
1. Electricity you use directly (self-consumption): Every kWh your panels produce that you use immediately saves you the full retail rate — $0.12–$0.46/kWh depending on your state.
2. Electricity you export to the grid (net metering): Every kWh you export earns a credit on your next bill. In most states this is the same retail rate. In some states (Indiana, Tennessee, Alabama, Mississippi, Idaho) it's a much lower "avoided-cost" rate of $0.03–$0.06/kWh.
The calculator accounts for both rates and uses the correct policy for your state.
Average Monthly Savings by State
The table below shows average first-year monthly savings for a typical homeowner (10 kW system, 80% annual offset, before any incentives or loan payments):
| State | Avg. Rate | Monthly Savings | Annual Savings |
|---|---|---|---|
| Hawaii | $0.42/kWh | $490–$565 | $5,900–$6,800 |
| Connecticut | $0.28/kWh | $280–$340 | $3,350–$4,100 |
| Massachusetts | $0.27/kWh | $270–$320 | $3,200–$3,900 |
| Rhode Island | $0.25/kWh | $250–$300 | $3,000–$3,600 |
| New Hampshire | $0.24/kWh | $240–$290 | $2,900–$3,500 |
| New York | $0.22/kWh | $200–$260 | $2,400–$3,100 |
| California | $0.28/kWh* | $185–$250 | $2,200–$3,000 |
| New Jersey | $0.18/kWh | $175–$225 | $2,100–$2,700 |
| Florida | $0.15/kWh | $175–$215 | $2,100–$2,600 |
| Texas | $0.14/kWh | $160–$210 | $1,900–$2,500 |
| Arizona | $0.13/kWh | $155–$205 | $1,850–$2,460 |
| Colorado | $0.14/kWh | $145–$185 | $1,740–$2,220 |
| National Average | $0.17/kWh | $100–$150 | $1,200–$1,800 |
| Indiana | $0.14/kWh* | $55–$90 | $660–$1,080 |
| Tennessee | $0.12/kWh* | $45–$75 | $540–$900 |
*California uses NEM 3.0 (battery storage strongly recommended). Indiana and Tennessee mark avoided-cost export states — size your system to 85–90% of annual consumption to avoid exporting at $0.03–$0.05/kWh.
Why High-Rate States Beat Sunny States
This is the counterintuitive fact every buyer should know: electricity rate matters more than sunshine for dollar savings.
Connecticut has 4.5 peak sun hours per day vs. Arizona's 6.0 — yet a Connecticut homeowner saves $280–$340/month vs. Arizona's $155–$205/month because Connecticut's $0.28/kWh rate is more than twice Arizona's $0.13/kWh.
Every kWh your panels produce is worth more in Connecticut than in Arizona. The math is straightforward:
- Connecticut: 1 kWh saved × $0.28 = $0.28 in bill reduction
- Arizona: 1 kWh saved × $0.13 = $0.13 in bill reduction
This is why the Northeast solar states — particularly Connecticut, Massachusetts, Rhode Island, and New Hampshire — consistently have faster payback periods than sunnier states like Arizona and Nevada.
How to Use Your Calculator Results
Monthly savings figure: This is your Year 1 estimate before accounting for system loan payments. Compare this to your current monthly electricity bill to understand your net monthly cash flow with a solar loan.
Payback period: The year your cumulative solar savings equal your net system cost (after 30% federal ITC). A payback under 8 years is excellent; under 12 years is good; over 15 years suggests you should focus on self-consumption design or wait for a better rate environment.
25-year cumulative savings: The total electricity cost you'll avoid over the system's life. Subtract your net system cost to get your net 25-year profit.
System size recommendation: Based on your monthly bill and state solar resource, the calculator recommends the kW system that covers 90% of your annual usage. Sizing at 90% (rather than 100%) leaves a small grid connection for the cheapest nighttime power and avoids year-end avoided-cost credit losses in most states.
Net Metering Warning: 8 States to Right-Size Carefully
In most states, exported solar earns the same full retail credit as power you use directly. But in 8 states, exported power earns only the "avoided cost" — typically $0.03–$0.06/kWh vs. $0.12–$0.16/kWh retail.
Avoided-cost states (size to 85–90% of annual consumption):
- Indiana (AES/Duke territories)
- Tennessee (TVA Green Power Providers, plus $15.64/month Power Service Connection fee)
- Alabama (Alabama Power territory)
- Mississippi (Entergy/Mississippi Power territory)
- Idaho (Idaho Power annual October true-up)
- Wyoming (Rocky Mountain Power annual October true-up)
- Montana (NorthWestern Energy annual true-up)
- Missouri (annual avoided-cost year-end settlement)
The calculator automatically applies the reduced export rate for these states and shows you how much an oversized system would cost you annually.
California: NEM 3.0 Changes the Calculation
California's NEM 3.0 (effective April 2023) cut export credits from ~$0.30/kWh to ~$0.05/kWh. This fundamentally changes the savings calculation for new California installations:
- Self-consumed kWh: saves $0.28–$0.35/kWh (excellent)
- Exported kWh: earns $0.04–$0.08/kWh (poor)
California NEM 3.0 buyers should target 150–200% self-consumption — meaning most production is used on-site and battery storage is strongly recommended to shift afternoon production to evening usage. The calculator reflects this by showing your NEM 3.0 export rate when California is selected.
For the full California solar picture, see the California solar incentives guide.
SREC and PBI States: Additional Savings Not in the Calculator
Six states pay solar owners additional income on top of electricity savings through performance-based incentives (PBI) or solar renewable energy certificates (SRECs). The calculator shows electricity bill savings only — add these on top:
| State | Program | Additional Annual Income |
|---|---|---|
| Massachusetts | SMART | $1,200–$2,000/year for 10 years |
| Connecticut | RSIP | $1,400–$2,200/year for 6 years |
| Illinois | Shines | $1,000–$1,600/year for 15 years |
| New Jersey | SREC II | $1,400–$2,200/year for 15 years |
| Maryland | SREC | $540–$810/year (market rate) |
| Minnesota | Xcel Solar*Rewards | $600–$1,000/year for 10 years |
Buyers in these states should add PBI/SREC income to the calculator's electricity savings for their full annual benefit.
How the Calculator Determines Your System Size
The Solar Savings Calculator uses this sizing formula:
Annual kWh usage = monthly bill ÷ electricity rate × 12
System size (kW) = Annual kWh ÷ (365 × peak sun hours × derate factor × 0.90 offset)
Where:
- Peak sun hours = state-specific average (3.8 hr/day for Seattle to 6.5 hr/day for Phoenix)
- Derate factor = 0.82 (accounting for real-world losses from temperature, wiring, inverter efficiency, soiling)
- 0.90 = recommended 90% annual offset
For a Boston homeowner using 900 kWh/month:
- Annual kWh = 10,800
- System size = 10,800 ÷ (365 × 4.1 × 0.82 × 0.90) = 9.8 kW
The calculator rounds to the nearest 0.5 kW and uses a standard $/W cost for your state.
From Calculator to Actual Quotes
Your calculator estimate is a starting point — not a final quote. The next step is getting 2–3 competitive installer quotes:
- Use the calculator to get your estimated system size and savings
- Get 3+ installer quotes — any quote more than 20% above the calculator's estimated cost is likely overpriced
- Compare production estimates — verify installer kWh projections using PVWatts (our production estimates guide explains how)
- Calculate your own payback — use the Solar Financing Calculator to see cash vs. loan vs. lease costs over 25 years
See also our Solar ROI Calculator to assess whether solar makes financial sense given your specific situation, and the Solar System Designer to size your system and generate an Amazon parts list for DIY comparison.
Frequently Asked Questions
How accurate is the solar savings calculator? The calculator provides a reliable estimate within ±15% for most homeowners. Actual savings vary based on your specific roof orientation, shade, local electricity rate plan, and net metering policy. Your installer's quote should include a site-specific production estimate using tools like Aurora Solar or PVWatts.
Does the calculator account for rising electricity rates? Yes — the 25-year savings model uses a 4% annual electricity rate escalation (the long-term U.S. average). You can adjust this in the calculator. Higher rate assumptions increase your 25-year savings; lower rates reduce them.
Should I use the monthly bill or monthly kWh input? Either works. If you know your bill amount, use the bill toggle — the calculator divides by your state's average rate to estimate your kWh. If you know your kWh from your utility bill, that input is slightly more accurate.
What does the verdict tier mean?
- Excellent (≤7 years payback): Solar is clearly worth it; top quartile nationally
- Good (7–10 years): Strong investment with above-average returns
- Moderate (10–15 years): Solar still profitable but consider maximizing self-consumption
- Lower (15+ years): May want to reassess system size, financing, or consider community solar
How is the payback period calculated? Net system cost (after 30% ITC) ÷ annual electricity savings. The calculator uses your state's current rate and does not include SREC/PBI income, home value increase, or avoided future rate increases — all of which improve the actual payback.
Next Steps
After using the calculator:
- Solar ROI by State: Which State Has the Best Solar Returns? — full 50-state ranking by payback period and 25-year savings
- How Much Does Solar Save on Your Electric Bill? — detailed state-by-state savings breakdown
- Solar Financing Calculator — compare cash vs. loan vs. lease total cost over 25 years
- Solar System Designer — size your full system and generate an Amazon parts list
- How to Compare Solar Quotes — evaluate installer proposals once you have your estimate
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