Solar Panel System Cost Calculator

Estimate the cost to install rooftop solar panels. Calculate system size, total cost, federal tax credit, payback period, and 25-year savings for your home.

☀️ Energy📐 Solar Cost = System kW x Cost per Watt - Incentives

Annual electricity usage (kWh)

Electricity rate ($/kWh)

Average daily sun hours

Cost per watt installed ($)

Please enter valid values.

Formula & Reference

Variable	Formula	Units
Solar Panel System Cost Calculator	Solar Cost = System kW x Cost per Watt - Incentives	$ estimate

Step-by-Step Examples

Example 1

Average US Home

10,000 kWh/year, $0.13/kWh, 4.5 sun hours, $3.00/W.

System: 6.08 kW (~15 panels)
Gross: 6,080W x $3.00 = $18,240
IRA credit: -$5,472 | Net: $12,768
Annual savings: $1,300 | Payback: 9.8 years
25-yr savings: $19,732

✓ $12,768 net / 9.8-year payback

Example 2

High Electricity Rate

12,000 kWh, $0.20/kWh, 5 sun hours, $2.90/W.

System: 6.58 kW
Net cost: $13,356
Annual savings: $2,400 | Payback: 5.6 years

✓ $13,356 net / 5.6-year payback

Example 3

Small Efficient Home

6,000 kWh, $0.13/kWh, 4 sun hours, $3.00/W.

System: 4.11 kW (~10 panels)
Net: $8,631
Annual savings: $780 | Payback: 11.1 years

✓ $8,631 net / 11-year payback

Real-World Applications

🏠

Homeowners

Calculate the true cost and payback of going solar.

☀️

Solar Installers

Quick system sizing and ROI estimate for sales consultations.

💰

Financial Planners

Evaluate solar as an investment vs other financial options.

⚡

Energy Auditors

Integrate solar savings into whole-home energy reduction planning.

Common Mistakes to Avoid

⚠️

Not accounting for electricity rate increases

Solar payback improves significantly if electricity rates rise. US electricity prices have increased 3-4% annually. A 3% rate increase shortens payback by 1-2 years on most systems.

⚠️

Ignoring shading and orientation

South-facing panels with no shading produce 20-30% more than east/west or partially shaded panels. Get a site assessment; shading from trees, chimneys, or neighboring buildings significantly reduces output.

⚠️

Not comparing multiple installers

Solar prices vary 20-30% between installers. Get 3+ quotes. Compare equipment quality (panel wattage, inverter type, warranty) as well as price. Check NABCEP certification and installer reviews.

Frequently Asked Questions

How much do solar panels cost in 2024? ▾

The national average is $2.85-$3.50 per watt installed. A 6 kW system averages $17,000-$21,000 before incentives. After the 30% federal tax credit, cost drops to $11,900-$14,700. Prices have dropped 70% since 2010.

What is the federal solar tax credit? ▾

The IRA (2022) provides a 30% federal tax credit on solar panel installation costs through 2032, dropping to 26% in 2033 and 22% in 2034. This applies to residential systems and reduces federal taxes owed (not just a deduction).

How long do solar panels last? ▾

Most quality panels are warranted for 25 years with 80%+ power output. Actual lifespan: 30-40+ years. Solar systems typically pay back in 7-12 years, then provide free electricity for 15-30+ more years.

What is net metering? ▾

When solar panels produce more electricity than you use, excess power flows back to the grid and your meter runs backward. You receive credits on your bill. Net metering policies vary by state and utility; some pay less than retail rate for exported power.

Do solar panels increase home value? ▾

On average, solar panels add $4-6 per watt of installed capacity to home value (Lawrence Berkeley National Laboratory research). A 6 kW system adds approximately $24,000-$36,000 in home value in many markets.