How Solar Panels Are Priced
A residential solar quote usually arrives as one big number with a monthly payment attached. Breaking that number down is the only way to compare offers, spot padding, and avoid the most expensive mistake in solar buying — the financing.
Dollars per watt: the number to compare
The standard unit for comparing solar prices is $/W: total system price divided by system size in watts. A 7,000 W (7 kW) system quoted at $21,000 is $3.00/W. This normalises for system size, so you can compare a quote for your roof against state averages and against other bids for different-sized systems.
US residential solar is roughly $2.50–$3.50/W before incentives, varying by state, installer, and equipment. Anything much above $3.50/W deserves scrutiny; anything below $2.30/W may involve budget equipment or a thin workmanship warranty — ask what you are getting.
Where the money goes
For a typical cash-price system:
| Component | Rough share of price |
|---|---|
| Panels (modules) | 15–20% |
| Inverter(s) | 10–15% |
| Racking, wiring, conduit, electrical | ~10% |
| Installation labour | 15–20% |
| Permitting, inspection, utility interconnection | 5–10% |
| Sales, marketing, customer acquisition, overhead, margin | 25–35% |
That last row is why two quotes for the same hardware can differ by a third. Panel and inverter costs are broadly similar across the country; customer acquisition cost and margin are not. A company that gets you through a referral has far lower overhead than one that knocked on your door or bought your lead from a call centre.
Equipment tiers
- Panels. Mainstream mono-PERC or TOPCon panels (400–450 W) are the right choice for most homes. Premium brands cost more per watt for a few percentage points of efficiency — worth it only when roof space is genuinely tight and you cannot fit enough standard panels to cover your usage.
- Inverters.
- String inverter — cheapest, one central unit. Simplest, but the whole string’s output drops to the level of its most-shaded panel, and it is a single point of failure. Fine for a simple, unshaded roof.
- String inverter + power optimizers — per-panel optimisation with a central inverter. A middle option, good with mild shading.
- Microinverters — one small inverter per panel. Most expensive, best performance under shading or on complex multi-plane roofs, easiest to expand later, and no single point of failure. Typically warrantied 25 years.
- Warranties. 25 years on panels (product and performance) and 10–25 on inverters is standard. The installer’s workmanship warranty — covering roof penetrations and labour — matters as much as the manufacturer warranty, and 10+ years is a good sign the company expects to still be around.
How financing quietly inflates the price
This is the single biggest trap in residential solar. Dealer-financed solar loans — the “$0 down, low monthly payment” offers — frequently carry a dealer fee of 15–30% that is baked into the system price and not shown as a line item. The identical panels on the identical roof can cost $21,000 cash or $27,000 on the “same as cash” loan.
Protect yourself:
- Ask for the cash price and the financed price separately, in writing.
- If the financed price is higher, that difference is the hidden fee — compare it to the interest you would pay on a home equity loan or HELOC, which is usually far cheaper.
- Paying cash, if you can, avoids the fee entirely and shortens the payback.
Leases and PPAs have no upfront cost, but the provider owns the system, keeps the incentives (including the commercial tax credit), and often includes an annual payment escalator of 1–3%. Your lifetime savings are smaller, and the contract can complicate a future home sale.
Reading a quote line by line
A proper solar quote should break out at least these items. If a salesperson gives you only a total and a monthly payment, ask for the itemisation:
| Line | What to check |
|---|---|
| System size (kW DC) | Does it roughly match your annual usage? Bigger is not better if exports pay little |
| Panel make, model, wattage, quantity | Tier-1 manufacturer? 25-year product + performance warranty? |
| Inverter type and model | String, string + optimizers, or micro — and does it suit your roof’s shading? |
| Racking / attachments | Flashed roof penetrations; who warranties leaks and for how long |
| Monitoring | Included, and is there an ongoing fee? |
| Electrical work / main panel upgrade | Panel upgrades ($1,500–4,000) are a common hidden add |
| Permitting & interconnection fees | Should be a modest line, not a large one |
| Price per watt (cash) | Total ÷ watts. Compare to $2.50–3.50 |
| Price per watt (financed) | If higher than cash, the difference is the dealer fee |
| Production estimate (kWh/year) | With the assumed shading and orientation stated |
| Warranties | Product, performance, inverter, and installer workmanship (10+ years is good) |
Get this from three installers on the same system size and you can compare them in ten minutes.
What to do
- Get three quotes from installers with local track records.
- Convert each to $/W and compare.
- Compare the equipment (panel model and wattage, inverter type, warranties).
- Get the cash price in writing for each.
- If financing, price a home equity loan against the solar loan.
The solar savings calculator uses a state-typical $/W to estimate system cost, so you have a benchmark in hand before the sales calls start.
The bottom line
Compare solar quotes on dollars per watt, expect $2.50–$3.50/W before incentives, and know that a quarter to a third of the price is sales and margin — which is where the spread between bids comes from. The costliest mistake is dealer financing: always get the cash price, and compare a HELOC before signing a solar-specific loan.