Solar Panel Savings Calculator

Estimate whether rooftop solar makes financial sense before you request quotes. Enter your system size, monthly bill, local electric rate, and installation assumptions to see expected savings, payback time, and long-term net value.

System Size (kW)

Average home system is 5-8 kW.

Monthly Electric Bill ($)

Peak Sun Hours/Day

Average is 4-6 hours. Southern states get more.

Electricity Rate ($/kWh)

Cost Per Watt ($)

Before tax credits. Average is $2.50-$3.50.

System Efficiency (%)

Accounts for inverter losses, shading, etc.

How to Use

1 Enter your desired system size in kW (average home: 5-8 kW).

2 Enter your monthly electric bill.

3 Enter peak sun hours for your location (4-6 average).

4 Enter your electricity rate per kWh.

5 Enter the cost per watt for installation.

6 Adjust system efficiency to account for inverter losses, shading, and roof conditions.

7 Click Calculate to see your solar savings.

Formula

Daily Production kWh/day = System Size x Sun Hours x Efficiency

Monthly Production Monthly kWh = Daily Production x 30

Monthly Savings Savings = min(Monthly kWh x Rate, Monthly Bill)

Payback Period Years = System Cost / Annual Savings

Conversion Chart

6 kW System Example

A 6 kW system with 5.5 sun hours/day, an electricity rate of $0.20/kWh, a cost of $2.80/watt, and 85% efficiency produces about 841.5 kWh/month. That offsets roughly $142/month and $1,704/year, leading to a payback period of about 9.9 years before incentives or financing costs.

Why It Matters

Solar sales quotes can sound attractive, but the real question is how quickly the system pays for itself and what you keep after that. Looking at monthly savings, installed cost, and payback together makes it easier to compare cash purchase, financed, and do-nothing options.

Who Uses This Calculator?

• Homeowners and renters estimating electricity costs, appliance usage, solar savings, or EV charging expenses.
• Solar shoppers, EV owners, and households comparing energy upgrades before requesting quotes or changing usage habits.
• Anyone who wants a quick estimate of home energy costs using clear assumptions.

Frequently Asked Questions

How much do solar panels cost?

The average cost is $2.50-$3.50 per watt before tax credits. A typical 6kW system costs $15,000-$21,000 before the 30% federal tax credit.

How long do solar panels last?

Most solar panels have a 25-30 year warranty and can last 30-40 years. They lose about 0.5% efficiency per year.

What is the federal solar tax credit?

The federal Investment Tax Credit (ITC) gives you 30% back on solar installation costs through 2032, then decreases.

Do solar panels work on cloudy days?

Yes, but at reduced efficiency (10-25% of full output). Solar panels work best with direct sunlight but still generate power on cloudy days.

Does this calculator include batteries, financing, or maintenance?

No. This estimate focuses on panel production, utility savings, and basic system cost. Batteries, loan interest, roof work, permit fees, and maintenance can change the economics and should be added separately when comparing real quotes.

Related Guides

Solar Panel Guide

Understand solar sizing, savings, incentives, and payback before comparing quotes.

Solar Payback Guide

Understand solar payback period, net system cost, incentives, and savings assumptions.

All Calculators

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This calculator provides estimates for informational purposes only. Verify results with a qualified professional for important decisions.