This research-based guide contains no affiliate tracking, paid placement, contractor ranking, savings promise, or claim of inspecting an installation. Building conditions, codes, incentives, financing, and professional requirements vary; verify current local and official information.
Evaluate home solar by roof and site conditions, measured energy use, system design, production assumptions, utility rules, purchase or lease terms, warranties, installers, and total cost.
First decide whether the property fits
Solar output depends on sunlight, orientation, tilt, shading, roof area, local weather, equipment, and system losses. A remote image can start the conversation but should not silently replace a site assessment. Record tree shading, vents, chimneys, roof planes, electrical equipment, structural concerns, access, and any future construction.
The roof and solar timelines should align. Removing an array for roof replacement adds cost and coordination. If the roof may need work, use the roofing contractor question guide before finalizing either scope.
Use measured consumption, not a generic home
Collect at least a representative year of utility bills and monthly kilowatt-hour use when available. Note expected changes such as an electric vehicle, heat pump, addition, efficiency work, occupancy, or business equipment. A system sized to old usage may not match the future, while oversizing can have poor economics if utility credit rules are unfavorable.
Make proposals comparable
| Item | What to require | Why it matters |
|---|---|---|
| System design | Panel count and model, inverter type/model, layout, DC and AC ratings, batteries, and electrical work. | “A solar system” is not a complete specification. |
| Production | First-year estimate, model and weather assumptions, shading, losses, degradation, and guarantee terms. | Savings projections begin with production assumptions. |
| Utility | Interconnection, meter, export compensation, rate assumptions, fees, and approval owner. | Exported energy may not offset usage at the retail rate. |
| Price | Cash price, financed amount, fees, interest, escalators, incentives, and total scheduled payments. | A low monthly payment can hide term and finance cost. |
| Scope | Permits, engineering, roof/electrical work, trenching, monitoring, inspections, cleanup, and exclusions. | Unassigned work becomes delay or change-order risk. |
Purchase, loan, lease, or power agreement
With a cash purchase or loan, the homeowner generally owns the equipment, subject to financing and contract terms. A lease or power purchase agreement can shift some upfront cost and maintenance responsibility, while creating a long contract, payment escalator, production and performance terms, property-transfer process, and buyout rules.
Compare the cash price with the financed price and total payments. Ask who receives tax credits, rebates, renewable-energy certificates, export payments, and other benefits. Incentives and tax rules change; verify current eligibility with the administering authority and a qualified tax professional. A sales estimate is not tax advice.
Verify the installer and responsible parties
- Legal company name, physical contact information, licenses where required, insurance, and complaint history.
- Whether sales, design, permits, installation, electrical work, monitoring, and service are employees or subcontractors.
- Who holds the contract and who remains responsible if a subcontractor or equipment maker fails.
- Recent comparable projects and permission to verify references without relying on curated testimonials alone.
- Change-order approval, payment milestones, lien releases, cancellation rights, and dispute process.
- Realistic dates for site survey, design, permit, utility approval, installation, inspection, and permission to operate.
Separate the warranties
Panel product, panel performance, inverter, battery, racking, roof penetration, installation workmanship, and monitoring may have different providers, durations, exclusions, labor coverage, and claim processes. A long equipment warranty is less valuable if removal, shipping, diagnosis, labor, and reinstallation are excluded or the responsible company cannot be reached.
Battery questions
A grid-tied solar array commonly shuts down during an outage unless designed with appropriate isolation and backup equipment. Define which circuits must run, for how long, at what starting loads, and under which weather and state-of-charge assumptions. Confirm safe placement, code, ventilation, fire-service requirements, usable capacity, power rating, cycling, warranty throughput, monitoring, and replacement.
Pressure and savings claims
FTC guidance cautions consumers about misleading “free” solar and savings representations. Do not provide financial or identity information to an unexpected caller or visitor. Verify utility and government claims directly; get every rebate, rate, roof, warranty, and savings assumption in the contract. Retain the proposal version and all attachments before signing.
Bottom line
A strong solar decision begins with the property, measured consumption, current utility rules, and a documented design. Compare the same scope and financing horizon, not monthly-payment headlines. If electrification is part of the plan, coordinate load estimates with the heat pump versus furnace guide.
How we evaluated this page
We translated DOE and FTC solar guidance into criteria for site fit, load, design, production, utility interaction, proposals, installer evidence, contracts, financing, incentives, warranties, monitoring, maintenance, and transfer.
Read the full review methodologySources and reference notes
Sources were checked on August 20, 2026. Product capabilities and prices can change; verify purchase-critical details directly.
- U.S. Department of Energy: Homeowner’s Guide to Going Solar Primary federal guidance on site fit, options, bids, financing, and installation.
- DOE: Step-by-Step Guide for Consumers Going Solar Authoritative consumer process and decision stages.
- FTC: Solar Power for Your Home Consumer guidance on claims, contracts, financing, and fraud avoidance.