What a system costs, by size

Solar is priced by watts, the same unit on a light bulb. A system’s size is given in kilowatts (kW) — one kilowatt is 1,000 watts. Most homes need somewhere between 6 and 12 kW.

Panel counts assume 425-watt panels, which is typical right now — most panels sold today fall between 400 and 460 watts. Bigger panels mean fewer of them, not a cheaper system.

Those ranges are wide on purpose. A $20,000 quote and a $28,000 quote for the same 8 kW system are both perfectly normal, and the next section explains why.

You are not mostly buying panels

This surprises nearly everyone. On an average installation, the solar panels themselves account for roughly 12% of what you pay. A 400-watt panel costs an installer somewhere around $150 to $250 wholesale.

So if twenty panels cost the installer maybe $4,000, where does the other $20,000 go?

Why your price will differ from the table

Things that push the number up:

• A complicated roof. Multiple angles, dormers, skylights and chimneys all slow a crew down. A simple south-facing rectangle is the cheapest roof to work on.
• Steep pitch or three storeys. More safety equipment, more time.
• An old electrical panel. If your main service panel can’t handle the addition, it needs upgrading — commonly $2,000 to $4,000, and a genuine surprise to most homeowners.
• A roof near the end of its life. Panels last 25–30 years. If your shingles have 5 years left, you’ll want the roof done first, or you’ll pay to remove and reinstall the array later.
• Ground mounting. Typically 10–20% more than roof mounting, because of foundations and trenching.
• Battery storage. A separate purchase, covered below.
• Where you live. Permitting costs, labor rates and competition vary enormously by region, and this is one of the largest factors of all.

Things that pull it down:

• A bigger system. The price per watt falls as size rises — the truck roll, the design work and the permit cost the same whether the array is 6 kW or 12 kW.
• A competitive local market. More installers means lower prices.
• A simple, accessible roof with no upgrades needed.
• Getting three quotes. Consistently the cheapest thing you can do to lower your price, and it costs you nothing but time.

What about batteries?

A battery stores power for use at night or during an outage. It is a separate decision from solar and a substantial one — adding storage can nearly double your project cost.

Home batteries run roughly $1,000 per kilowatt-hour of storage installed, though the spread is wide. A common single-unit setup of around 13 kilowatt-hours lands somewhere in the region of $12,000 to $16,500 installed.

The one number that lets you compare quotes

Quotes are deliberately hard to compare. Different system sizes, different equipment, different financing, different bundled extras. There’s a simple way to cut through it.

Costs that arrive after the quote

Ask specifically whether each of these is included. Finding out later is how a project goes over budget:

• Electrical service panel upgrade
• Roof repair or replacement before installation
• Tree trimming or removal for shade
• Utility interconnection fees
• Permit fees, if quoted separately
• Monitoring subscription after the first year
• Critter guard, if you have squirrels — and eventually you will

Is it worth it?

That comes down to arithmetic only you can do, and it turns almost entirely on two numbers: what you currently pay per kilowatt-hour, and how much sun your roof gets.

Honest framing for 2026: with the federal credit gone for buyers, payback periods have stretched. A system that would have paid for itself in about 9 years now commonly takes 12 or more — longer where electricity is cheap, shorter where it’s expensive and state incentives are strong.

The panels themselves last 25 to 30 years, so a 12-year payback still leaves well over a decade of production you didn’t pay for. Whether that’s a good use of $25,000 compared with anything else you could do with $25,000 is a question about your finances, not about solar.