☀️ SolarPanelEstimator.com

15 kW Solar System

Cost, production, and savings — calculated for your location

✓ Free, instant, anonymous. No email required.

38

400W Panels

21.9k

kWh/Year (avg)

38.3k–46.5k

Installed Cost

A 15 kW solar system is a large residential or small commercial system — suited for high-consumption homes, small businesses, or homes with EVs and batteries. At average US sun hours, a system this size produces roughly 15,300–26,300 kWh per year, enough to power a large home or property with high electricity use. This calculator pre-loads a 15 kW system so you can explore the financials, adjust your state, and understand exactly what this system size would mean for your electricity bill.
Loading calculator…

15 kW Solar System — FAQ

How many solar panels does the average home need?▾
Most US homes need between 15 and 30 panels (6–12 kW system). The exact number depends on your electricity usage, your state's sun hours, roof orientation, and the wattage of the panels you choose. Enter your bill or usage above to get a personalized estimate.
What does kilowatt (kW) mean for a solar system?▾
Kilowatts (kW) measure the peak power output of a solar system under ideal conditions (full sun, optimal temperature). A 10 kW system with 400W panels requires 25 panels. In practice, systems produce less than their peak rating due to sun angle, temperature, and efficiency losses — which is why we use a 0.80 derate factor in our calculations.
How long does solar installation take?▾
The actual roof installation takes 1–3 days. However, the full timeline from signing a contract to system activation is typically 2–4 months, accounting for permit applications, utility interconnection approval, and inspection scheduling. Some fast-moving markets can complete the process in 6–8 weeks.
How much does a solar system cost installed?▾
Installed solar costs range from $2.50 to $3.50 per watt depending on your state, system size, panel brand, and installer. A 10 kW system runs $25,000–$35,000 before incentives. After the 30% federal ITC, that's $17,500–$24,500. Many states offer additional rebates that can reduce costs further. Get 3 quotes to find competitive local pricing.
Do solar panels increase home value?▾
Yes. Lawrence Berkeley National Lab found that solar homes sell for an average of $15,000 more than comparable non-solar homes. The value premium varies by market — it's higher in states with high electricity rates and strong solar markets. Buyers increasingly see owned solar systems as an asset, not a liability.

More Solar Calculators & Guides

→

Free Solar Panel Calculator

Size your system based on your actual bill and location

→

6 kW Solar System

Compare specs and savings for a 6 kilowatt array

→

10 kW Solar System

Compare specs and savings for a 10 kilowatt array

→

5 kW Solar System

Compare specs and savings for a 5 kilowatt array

→

Solar Savings for $250/Month Bills

How a 15 kW system handles a $250 monthly bill

→

Solar Savings for $100/Month Bills

How a 15 kW system handles a $100 monthly bill

→

Solar for 1,000 Sq Ft Homes

Is a 15 kW system right for a 1,000 sq ft home?

→

Illinois Solar Calculator

15 kW system savings in Illinois

→

California Solar Calculator

15 kW system savings in California

Disclaimer: System cost, production, and savings estimates are based on national averages. Select your state in the calculator above for location-specific estimates. Not financial advice.