What goes into the price?
The sections below break down each part of that equation so you can compare Massachusetts proposals on the same basis.
The six biggest cost drivers
1. System size
More panels generally increase the total price, although price per watt can change with system size.
2. Equipment
Panels, inverter architecture, racking, monitoring, and warranties can all affect price.
3. Roof and site conditions
Roof material, pitch, multiple roof planes, obstructions, structural work, and difficult access can add labor.
4. Electrical work
Panel upgrades, service changes, trenching, long conduit runs, and other electrical work can create meaningful adders.
5. Battery storage
A battery should be evaluated as a separate cost and benefit decision rather than automatically bundled into the solar economics.
6. Financing
Interest, dealer fees, term length, payment changes, and total payments can make two systems with the same cash price cost very different amounts.
How price per watt works
Price per watt is the cash project price divided by the system’s wattage. It is useful for comparing similarly scoped systems.
$18,000 ÷ 6,000 W = $3.00/W
$/W can be misleading if one quote includes a battery, roof work, electrical upgrades, or materially different equipment.
What can make a Massachusetts project different?
Permitting and interconnection
Requirements vary by municipality and utility. Eversource, National Grid, Unitil, and municipal utilities may have different processes.
Roof and electrical work
Older homes, roof condition, electrical upgrades, and complex roof layouts can materially change the project scope.
Local incentives and utility rules
Massachusetts programs and net-metering treatment can affect the economics, but they should be evaluated separately from the quoted installation price.
Last reviewed August 2026. Sources: Massachusetts net-metering eligibility and SMART 3.0 program details.
Compare cash price and financed cost separately
A quote should make these numbers easy to identify:
- Cash price
- Amount financed
- Interest rate
- Loan term
- Dealer or origination fees, if any
- Monthly payment
- Total payments over the loan
- Prepayment terms
A lower monthly payment can come from a longer term rather than a better-priced system.
What to compare across solar quotes
| Compare | Look for |
|---|---|
| System size | kW |
| Production | Estimated annual kWh |
| Cash price | Total before financing |
| Price per watt | Cash price ÷ system watts |
| Equipment | Panels, inverter, battery |
| Adders | Roof, electrical, trenching, and other site work |
| Financing | Rate, term, fees, and total paid |
| Ownership | Who owns the system |
| Warranty and service | Who handles problems |
Solar cost FAQ
What is included in a solar quote?
A useful proposal should identify the system design, equipment, labor, electrical work, permits, interconnection support, warranties, monitoring, and any battery or roof work. Compare exclusions as carefully as inclusions.
Is price per watt enough to compare systems?
Price per watt is useful when the proposals have similar system scope. It is not enough by itself if one quote includes a battery, roof work, electrical upgrades, or materially different equipment. Compare production, warranties, financing, and total paid too.