How to Read a Solar Proposal

System and price

Price per watt from our solar cost guide.

Production and savings assumptions

• Estimated annual production (kWh): ask how shading, roof direction and tilt were modeled.
• Degradation: panels produce a bit less each year; check the rate assumed.
• Offset: what share of your current use the system is expected to cover.
• Utility rate escalation: savings projections often assume rising electricity prices. A high assumed increase makes savings look larger.
• Net metering or export rates: how your utility credits excess power. Rules vary by state and utility and have changed in many places.
• Incentives: confirm each one is currently available. The federal residential credit for homeowner-owned systems ended for installations completed after 2025.

Warranties and guarantees

• Panel product warranty and performance warranty (output guaranteed over time).
• Inverter warranty.
• Workmanship warranty, including roof penetrations and leaks.
• Any production guarantee, and how shortfalls are paid.

Common exclusions

• Roof repairs or replacement; replacing an older roof first can avoid paying to remove and reinstall panels later (re-roofing with solar).
• Electrical panel upgrades (panel cost).
• Tree trimming or removal for shade.
• Trenching for ground mounts.
• Utility fees and HOA approvals.

Financing changes everything else; see buying vs. financing vs. leasing.