How to Compare Solar Companies: A Head-to-Head Quote Decision Guide (2026)

Solar installers make dozens of assumptions before they print a number. Two companies looking at the same roof can quote different system sizes, use different panel models, apply different shading algorithms, and project entirely different levels of production. Then add financing structures, ownership models, and which incentives each company counts as yours, and it's no wonder the totals diverge.

The most common sources of quote variation include system size (kW), panel efficiency and brand tier, production assumptions, incentive treatment, and ownership structure. Gross price-per-watt (total cost divided by system size in watts) ignores all of these variables. It's a useful sanity check, but it is not the number that determines which quote is actually better for you.

To compare bids fairly, convert each to net cost per watt after incentives you are personally eligible to receive. Then divide the net price by each installer's projected 25-year production to get a cost-per-kWh figure that accounts for system size differences.

A slightly larger or more efficient system may produce significantly more electricity over its lifetime, which can close a price gap that looks wide at first glance. Always confirm that 25-year projections account for panel degradation and shading losses, not just year-one output multiplied by 25.

Ask each installer to provide their shading loss percentage, soiling derate, degradation rate, and utility rate escalation assumption in writing. These four variables drive the bulk of variance in projected savings between quotes on identical roofs.

Stress-test rate escalation assumptions by asking for a scenario at 2% annual increase or flat rates. Panel degradation of approximately 0.5% to 0.8% per year is typical, according to the Department of Energy, and must be factored into any 25-year production estimate to be credible.

How you pay for solar changes the math significantly in 2026. For cash and loan buyers, the residential clean energy credit (Section 25D) has expired for systems placed in service after December 31, 2025, absent any Congressional extension. Always verify current credit status at IRS.gov and consult a qualified tax professional. For lease and PPA customers, the installer retains ownership and may claim the Section 48 commercial credit, which can influence lease pricing.

For financed purchases, scrutinize dealer fees, which can add 10% or more to effective system cost. For leases and PPAs, review annual payment escalator clauses carefully over the full contract term.

The company that sells you the system and the crew that installs it are not always the same. Ask whether the installation will be performed by in-house W-2 employees or third-party subcontractors, and ask whose workmanship warranty applies if the original installer closes its doors. Panel and inverter manufacturer warranties are separate and survive an installer closure, but only if you retain the original documentation.

Ask each installer how service calls are dispatched and whether a local office or technician covers your area for ongoing service needs.

Use a weighted rubric to score your two finalists across net cost per watt (25%), projected cost per kWh (20%), equipment tier (15%), warranty strength (15%), installer track record (15%), and financing terms (10%). Multiply each score by its weight and sum the results. The scorecard forces you to weigh all factors together rather than anchoring on price alone.

Adjust the weights to reflect your own priorities. If you are financing over 20 years, financing terms may deserve more weight. If you are a cash buyer focused purely on long-term return, cost per kWh may deserve more.

• First-visit hard close: Any installer who insists you sign today or lose the price is using a pressure tactic.
• False urgency claims: Unverifiable claims that a tax credit or utility program expires imminently are manipulation tactics.
• Vague equipment references: Demand specific panel and inverter model numbers in writing before comparing prices. "Tier 1 panels" with no model number is not a real specification.
• "We are your only option" framing: Exclusivity claims in a competitive national market are a red flag.
• Production guarantees with no methodology: If an installer cannot share the assumptions behind their projection, the estimate cannot be verified.