Solar Panel Cost by System Size in 2026: 6 to 12 kW

In 2026, home solar is priced per watt, and most U.S. installs land near $3.00 per watt (commonly $2.50–$3.50, depending on your state). That makes the common sizes easy to estimate: a 6 kW system runs about $18,000, 8 kW about $24,000, 10 kW about $30,000, and 12 kW about $36,000 — before any incentives. And because the 30% residential federal tax credit expired December 31, 2025, those gross numbers are also the net numbers for cash and loan buyers in 2026.

How system size, panels, and cost connect

A system's size in kilowatts is just the combined wattage of its panels. With today's common ~400-watt modules, the panel count is straightforward: divide the size by the panel wattage. The cost then scales with the size times your local price per watt. Higher-wattage panels (440–450 W) trim the count slightly but don't change the kilowatts you're buying.

Cost by system size

The table below uses a representative $3.00/W for the midpoint and a $2.50–$3.50/W band for the range. Annual production assumes roughly 1,200–1,500 kWh per kW per year, which varies with your sun; sunny states sit at the high end, cloudier ones lower.

System size	Panels (~400 W)	Cost @ $3.00/W	Typical range	Annual production	Fits a home using
6 kW	~15	~$18,000	$15,000–$21,000	~7,200–9,000 kWh	~7,000–9,000 kWh/yr
8 kW	~20	~$24,000	$20,000–$28,000	~9,600–12,000 kWh	~9,000–12,000 kWh/yr
10 kW	~25	~$30,000	$25,000–$35,000	~12,000–15,000 kWh	~11,000–15,000 kWh/yr
12 kW	~30	~$36,000	$30,000–$42,000	~14,400–18,000 kWh	~14,000–18,000 kWh/yr

Treat the production and "fits a home using" columns as guidance, not promises — your roof's tilt, orientation, and shading all move the real figure.

Why your price per watt varies

Two homes buying the same 10 kW system can pay thousands apart. The drivers:

• State and local labor. Installed price per watt ranges from around $2.20 in low-cost, high-volume markets to $3.50+ where labor and permitting are expensive.
• Roof complexity. Steep pitches, tile or metal roofing, and multiple planes add labor.
• Equipment. Premium all-black panels and microinverters cost more than baseline modules and a string inverter — see string vs. microinverter vs. power optimizer.
• System size itself. Fixed costs (permits, inverter, mobilization) spread across more watts, so bigger systems often see a slightly lower price per watt.

What size actually fits your usage

Don't buy a round number — buy the size that matches your electricity use. The average U.S. home uses roughly 10,000–11,000 kWh a year, which an 8–10 kW system usually covers depending on local sun. From there:

• 6 kW suits a smaller or efficient home (~7,000–9,000 kWh/yr).
• 8 kW fits a typical single-family home.
• 10 kW covers larger homes or those adding some electric load.
• 12 kW+ makes sense with an EV, a heat pump, or heavy central AC.

The cleanest way to size it is to start from your annual kWh and local sun hours rather than guessing. Our solar sizing calculator turns your usage into a recommended size and panel count, and the solar cost calculator translates that size into a 2026 install price with the real $0 federal credit baked in.

Bigger isn't always better

It's tempting to oversize "to be safe," but past your actual usage the economics weaken fast. Under net metering at 1:1, surplus export earns full retail and modest oversizing is harmless. Under NEM 3.0 or net-billing, exported kWh are credited well below retail, so panels that mostly export return little. Size to your consumption, then add a battery only if storage value (backup or arbitrage) justifies it.

The 2026 federal credit catch

The headline change this year: Section 25D, the 30% residential credit, expired December 31, 2025. A 10 kW system that effectively cost $21,000 after the old credit now costs the full ~$30,000 for cash and loan buyers — there's $0 federal credit in 2026. Only a lease or PPA provider that owns the panels can claim the commercial Section 48E credit. What that does to payback is covered in is solar worth it in 2026 and the 2026 solar tax credit guide.

Bottom line

• At ~$3.00/W, budget roughly $18k (6 kW), $24k (8 kW), $30k (10 kW), $36k (12 kW) before incentives.
• With ~400 W panels that's about 15 / 20 / 25 / 30 panels.
• Most homes fit an 8–10 kW system; size to your usage, not a round number.
• No federal credit in 2026 — gross equals net for cash and loan buyers.

Start from your own bill: size the system, then price it for your state with the real $0 federal credit baked in.

Open the solar cost calculator →