Wisconsin Solar Savings Calculator: 2026 Updated

Wisconsin Solar Savings Calculator

Calculate Wisconsin solar costs, 2026 federal tax-credit status, utility net metering, Focus on Energy rebates, payback period, and 25-year savings.

Wisconsin 2026 rules: No state solar income tax credit. The federal Section 25D credit ended for systems placed in service after December 31, 2025. Wisconsin mandates retail-rate net metering for investor-owned utilities with monthly rollover and annual true-up. Focus on Energy offers cash-back rebates for residential solar. No statewide property tax exemption for residential solar.

Loading calculator…

Estimates only. Verify utility rates, net metering true-up terms, rebate availability, county tax treatment, and federal tax status with your utility, installer, and tax professional.

What Is the Wisconsin Solar Savings Calculator?

The Wisconsin Solar Savings Calculator estimates the upfront expense and long-term financial benefits of a residential solar energy system. It uses installation costs, estimated electricity generation, household electricity usage, export credit rates, and financial assumptions to calculate net system cost, solar payback period, and cumulative net savings over 25 years.

The calculator helps Wisconsin homeowners understand how solar electricity production may affect household electricity expenses. It estimates the value of solar energy consumed directly at home and electricity exported to the utility grid.

It also includes editable fields for federal and state credit percentages, Focus on Energy or other rebates, annual utility solar fees, and property tax savings. These amounts affect the modeled financial results but do not establish eligibility for specific incentives.

The calculation uses a 25-year period, first-year solar electricity production of 1,250 kilowatt-hours (kWh) per kilowatt (kW) of installed capacity, and an annual solar production decline of 0.5%.

How the Wisconsin Solar Savings Calculation Works

The calculator first estimates the installation cost and subtracts entered incentives. It then models electricity production, self-consumption, grid exports, and financial benefits for each year over a 25-year period.

1. Calculate Gross Solar Installation Cost

The gross installation cost is calculated by converting solar system capacity from kilowatts to watts and multiplying by the entered installation price per watt.

G=S\times1{,}000\times C

Where:

G = Gross solar installation cost in dollars
S = Solar system capacity in kW
C = Installed cost per watt in dollars

For example, an 8 kW solar installation priced at $3.10 per watt has a gross cost of 8 × 1,000 × $3.10 = $24,800.

2. Calculate Net Solar System Cost

The calculator subtracts the dollar value of entered federal and state credit percentages and upfront rebates from the gross installation cost.

N=\max\left(0,G-G\frac{f}{100}-G\frac{s}{100}-R\right)

Here, N is net installation cost, f is the entered federal credit percentage, s is the entered Wisconsin state credit percentage, and R is the Focus on Energy or other rebate amount in dollars.

Both credit percentages are applied separately to the gross installation cost. The calculator prevents the resulting net cost from falling below zero.

The federal credit, state credit, and rebate inputs default to zero. The calculator’s 2026 informational notes describe the residential federal Section 25D credit as ended for systems placed in service after December 31, 2025, and indicate no Wisconsin state solar income tax credit. These fields remain editable for financial modeling.

3. Estimate Annual Household Electricity Usage

The calculator estimates annual household electricity consumption using the entered monthly electric bill and electricity rate.

U=\frac{12B}{r_0}

Where U is estimated annual electricity usage in kWh, B is the monthly electric bill in dollars, and r₀ is the starting electricity rate in dollars per kWh.

For a monthly electricity bill of $115 and an electricity rate of $0.170/kWh, estimated annual electricity consumption is approximately 8,118 kWh.

A positive electricity rate is necessary for a meaningful usage estimate because the formula divides annual electricity spending by that rate.

4. Calculate Annual Solar Electricity Production

The calculator estimates first-year solar electricity production using a fixed factor of 1,250 kWh per installed kW.

P_1=S\times1{,}250

Where P₁ is first-year solar electricity production in kWh, and S is installed system capacity in kW.

An 8 kW solar system therefore produces an estimated 10,000 kWh during its first year under the calculator’s assumptions.

The model then reduces annual electricity production by 0.5% after every year.

P_t=P_1(1-0.005)^{t-1}

Here, Pₜ represents estimated solar generation in year t.

Annual production is distributed across the months using fixed percentages. From January through December, the monthly production shares are 1%, 2%, 4%, 8%, 15%, 19%, 19%, 15%, 8%, 4%, 2%, and 3%.

These percentages total 100%. The monthly distribution affects how electricity is allocated between direct household consumption and grid exports.

5. Calculate Self-Consumed and Exported Solar Electricity

The calculator divides monthly solar generation into electricity used directly by the household and electricity exported to the grid.

A_m=\min\left(P_m\times\frac{u}{100},\frac{U}{12}\right)

X_m=\max(0,P_m-A_m)

Where:

Aₘ = Monthly self-consumed solar electricity in kWh
Pₘ = Monthly solar production in kWh
u = Entered daytime self-consumption percentage
U = Estimated annual household electricity usage in kWh
Xₘ = Monthly exported solar electricity in kWh

The calculator limits monthly self-consumed electricity to the home’s estimated monthly usage. Remaining solar generation is treated as exported electricity.

Self-consumed electricity is valued at the entered retail electricity rate, while exported electricity is valued at the entered export credit rate. Both rates increase annually according to the selected utility rate increase percentage.

6. Calculate Annual Solar Financial Benefits

For each modeled year, the calculator adds the financial value of self-consumed electricity and exported electricity. It then subtracts annual utility solar fees and adds entered annual property tax savings.

V_t=\sum_{m=1}^{12}(A_{m,t}r_t+X_{m,t}e_t)-F+T

In this formula, Vₜ represents annual financial benefits, A represents self-consumed electricity, X represents exported electricity, r represents the retail electricity rate, e represents the export credit rate, F represents annual utility solar fees, and T represents annual property tax savings. The subscripts m and t indicate the month and year.

The entered annual utility rate increase applies to both electricity rates. Annual utility fees and property tax savings remain fixed dollar amounts throughout the 25-year model.

7. Calculate Payback Period and 25-Year Net Savings

The calculator adds financial benefits for 25 years and subtracts the net upfront installation cost.

\text{25-Year Net Savings}=\sum_{t=1}^{25}V_t-N

The payback period is the first whole year when accumulated modeled financial benefits equal or exceed the net installation cost.

If net installation cost is zero, the calculator displays “Immediate.” If the cost is not recovered within the 25-year modeling period, it displays “25+ Years.”

Worked Example: 8 kW Solar System in Wisconsin

Consider a hypothetical solar installation using the calculator’s default values.

Calculator Input	Example Value
Monthly electric bill	$115
Electricity rate	$0.170/kWh
Solar system size	8 kW
Installed cost per watt	$3.10
Export credit	$0.170/kWh
Daytime self-consumption	30%
Annual utility rate increase	3.5%
Annual utility solar fees	$0
Federal and state credit percentages	0%
Focus on Energy / rebates	$0
Annual property tax savings	$0

Gross installation cost is $24,800. With no entered credits or rebates, the net installation cost remains $24,800.

Estimated first-year solar electricity production is 10,000 kWh, while annual household electricity consumption is approximately 8,118 kWh.

Under the first-year production pattern and 30% daytime self-consumption assumption, the model calculates 3,000 kWh of self-consumed electricity and 7,000 kWh of exported electricity.

Because both the retail electricity rate and export credit rate are $0.170/kWh, the first-year electricity value is 10,000 × $0.170 = $1,700.

With no annual solar fees or property tax savings entered, the first-year modeled financial benefit is also $1,700.

After applying annual electricity rate increases of 3.5% and solar production degradation of 0.5% over 25 years, the model produces these results:

Gross system cost: $24,800
Net system cost: $24,800
First-year solar production: 10,000 kWh
Estimated annual household electricity usage: 8,118 kWh
Solar offset: 123%
Payback period: 13 years
25-year cumulative modeled benefits: Approximately $61,839
25-year net savings: Approximately $37,039
25-year CO2 offset: 106.0 tons

These values follow the calculator’s mathematical assumptions. They are not guaranteed savings or predictions of actual solar performance. The current calculator also has several result-label limitations explained below.

How to Use the Wisconsin Solar Savings Calculator

Enter your monthly electric bill. Provide your electricity expense in dollars. The default is $115.
Enter your electricity rate. Use a positive rate in dollars per kWh. The default is $0.170/kWh.
Enter the solar system size. Provide the proposed installation capacity in kilowatts. The default is 8 kW.
Enter the installed cost per watt. Provide the installation price in dollars per watt. The default is $3.10.
Select your electric utility. Available options include We Energies, Wisconsin Public Service, Xcel Energy Wisconsin, Madison Gas and Electric, and Cooperative or Municipal. The selection itself does not change the calculation.
Adjust the export credit rate. Enter the assumed dollar value of electricity exported to the grid. The default is $0.170/kWh.
Set daytime self-consumption. Enter the percentage of generated electricity assumed to be used directly at home, from 0% to 100%.
Enter annual utility assumptions. Set the annual electricity rate increase, from 0% to 50%, and enter recurring annual solar-related utility fees.
Review incentive inputs. Enter applicable federal and Wisconsin state credit percentages, Focus on Energy or other rebates, and annual property tax savings. Credit percentages accept values from 0% to 100%.
Click “Calculate Savings.” Review the cost breakdown, payback period, 25-year net savings, and production results.
Click “Reset” when needed. This restores the calculator’s default inputs and hides the previous results.

The payback period indicates the first modeled year when accumulated benefits recover net installation cost. The 25-year net savings result shows the financial benefit remaining after subtracting that cost from total modeled savings.

Understanding Your Solar Savings Results and Assumptions

The calculator displays installation costs, financial results, solar electricity production, and estimated environmental impact. Understanding these outputs helps you interpret the model without confusing estimated savings with guaranteed financial returns.

Gross Cost, Incentives, and Net Cost

Gross System Cost represents the installation price before deductions. Federal Credit, State Credit, and Rebates / Focus on Energy show the entered incentive amounts as deductions. Net Cost is the remaining upfront expense used for the payback calculation.

Dollar results use U.S. currency formatting without decimal places. The displayed whole-dollar amounts are rounded, while the underlying calculations use unrounded values.

Payback Period and 25-Year Savings

The payback period measures how long modeled cumulative financial benefits take to recover the net upfront installation cost. The calculator displays the result in whole years and includes a visual meter comparing the payback period with its 25-year model.

Positive 25-year net savings indicate that accumulated modeled benefits exceed the net system cost. Negative savings indicate that the modeled benefits are insufficient to recover that cost over 25 years.

The calculation does not discount future savings to present value. It also does not separately model solar financing interest, loan payments, ongoing maintenance expenses, or equipment replacement costs.

Solar Offset and Electricity Production

The Production and Impact section displays system size, first-year solar production, estimated annual household electricity usage, and solar offset.

Solar offset compares estimated first-year solar generation with estimated annual household electricity consumption.

\text{Solar Offset (\%)}=\frac{\text{Year 1 Solar Production}}{\text{Annual Electricity Usage}}\times100

The displayed percentage is rounded to a whole number. If estimated annual electricity usage is zero or otherwise nonpositive, the code uses a solar offset value of 0%.

A solar offset above 100% means estimated annual solar generation exceeds estimated annual consumption. It does not necessarily mean the household uses all generated electricity directly or eliminates every utility charge.

25-Year Carbon Dioxide Offset

The calculator estimates cumulative carbon dioxide offset using total modeled solar electricity generation over 25 years and a fixed factor of 0.45 tons per 1,000 kWh.

\text{CO2 Offset (tons)}=\frac{\text{25-Year Production (kWh)}}{1{,}000}\times0.45

The result is displayed to one decimal place. It represents a simplified environmental estimate rather than a measurement of actual emissions avoided by an individual installation.

Focus on Energy Rebates and Wisconsin Incentives

The calculator includes a Focus on Energy / Rebates ($) input. You can enter an upfront rebate amount, and the calculator subtracts that amount from gross installation cost when determining net cost.

The interface identifies Focus on Energy as a possible source of residential solar cash-back incentives. However, the calculator does not automatically determine available rebate amounts, verify eligibility, or check whether funding remains available.

The calculator’s informational notes also describe Wisconsin as having no state solar income tax credit and no statewide residential solar property tax exemption. Accordingly, the state credit and annual property tax savings fields default to zero.

These inputs remain editable. Any entered credit or rebate reduces modeled installation cost, while entered annual property tax savings increase the modeled yearly financial benefit. Users should verify applicable incentives before including them in an actual project budget.

Wisconsin Net Metering Assumptions

The calculator includes informational notes describing retail-rate net metering, monthly credit rollover, and annual true-up arrangements for investor-owned utilities. It also indicates that cooperative and municipal utility terms may differ.

However, the numerical model values exported electricity using the entered Export Credit ($/kWh) rate. It does not separately calculate monthly credit rollover balances, annual avoided-cost settlements, or utility-specific tariff adjustments.

The selected utility does not automatically adjust the export credit rate or other financial inputs. Review the applicable utility terms before selecting an export credit assumption.

Important Calculator Display Limitations

Several details in the current implementation require attention when interpreting the displayed results:

Year 1 Self-Use kWh: Despite its label, this result currently displays self-consumed electricity from the final modeled year, year 25. With the default inputs, it shows approximately 2,660 kWh rather than the actual modeled first-year value of 3,000 kWh.
Year 1 Export kWh: This result also displays year 25 exported electricity rather than first-year exports. With default inputs, it shows approximately 6,207 kWh rather than 7,000 kWh.
Net Year 1 Savings: Despite the label, this row displays the greater of zero and the calculated 25-year net savings. It does not show the actual first-year financial benefit. The separate 25-Year Net Savings output displays the lifetime result directly.
Battery storage checkbox: Selecting the battery storage or high daytime self-use option does not directly modify the calculation. The Daytime Self-Consumption (%) input controls the modeled self-consumption amount.
Utility selection: Choosing another utility does not automatically update electricity rates, export credit rates, or other financial assumptions.
Net-metering and incentive badges: These are informational labels and do not independently confirm eligibility or current program terms.

All financial results are estimates based on user-entered values and fixed modeling assumptions. Actual solar generation, installation expenses, electricity rates, utility charges, and incentive eligibility may differ. Review project assumptions with a solar installer, utility, and tax professional where appropriate.

Frequently Asked Questions

How much can solar panels save in Wisconsin?

Potential solar savings depend on system size, installation cost, electricity prices, daytime self-consumption, export credits, and recurring expenses. The calculator models annual financial benefits over 25 years and subtracts net installation cost. Different inputs produce different savings estimates, so the results should not be considered guaranteed financial returns.

How does the Wisconsin Solar Savings Calculator determine payback time?

The calculator adds yearly modeled financial benefits until the cumulative amount equals or exceeds the net installation cost. The first whole year meeting that condition becomes the payback period. If the system does not recover its cost within 25 years, the calculator displays “25+ Years.”

Does the calculator include Focus on Energy solar rebates?

Yes. The calculator has a Focus on Energy / Rebates ($) field for entering an upfront rebate amount. That amount is subtracted from gross installation cost when calculating net cost. However, the calculator does not automatically check current rebate availability, program funding, or household eligibility.

Does the calculator account for solar panel degradation?

Yes. The calculator reduces annual solar electricity production by 0.5% after each year. This affects estimated future electricity savings, cumulative production, and the 25-year carbon dioxide offset. The degradation rate is fixed in the code and cannot be changed through a separate input field.

Does Wisconsin solar net metering affect the savings calculation?

Yes. The calculator values exported solar electricity using the entered Export Credit ($/kWh) rate. Changing that rate changes the modeled value of exported electricity. The tool also displays net-metering information, but it does not separately model monthly credit balances, annual true-up adjustments, or utility-specific settlement calculations.

Can adding battery storage increase the calculated savings?

The battery storage checkbox does not directly change the current calculation. You can adjust the daytime self-consumption percentage to explore how using more solar electricity at home affects its modeled financial value. However, the calculator does not separately estimate battery installation costs, storage capacity, or battery-specific savings.

Can the 25-year solar savings result be negative?

Yes. The 25-year net savings result can be negative when accumulated modeled financial benefits are lower than the net installation cost. Higher installation expenses, lower electricity values, reduced export credits, or recurring utility fees may contribute to this outcome. A negative estimate reflects the selected assumptions rather than a guaranteed financial loss.

Table of Contents

Wisconsin Solar Savings Calculator