20 Questions to Ask Solar Installers Before You Sign

Start with the pricing section. These questions help you compare quotes on an apples-to-apples basis and spot hidden markups.

This is the single most important number for comparing quotes. Divide the gross system price by the system size in watts. The national average in 2026 is $2.50–$3.50/W, varying by state and system complexity (LBNL Tracking the Sun 2024). If one installer quotes $3.00/W and another quotes $4.50/W, ask why. The answer may reveal differences in equipment quality, roof complexity, or unnecessary markups.

A complete solar quote should include panels, inverter, racking, wiring, permits, labor, monitoring, and interconnection application. Ask specifically: is monitoring included? Is the main panel upgrade included if needed (costs $1,500–$3,000)? Is tree trimming or roof work included? Are HOA or other application fees included? Anything not listed is a potential add-on charge later.

Loan pricing typically includes dealer fees that add 15–30% to the system cost (EnergySage Marketplace Intel). Some installers only present the loan option because the monthly payment looks affordable. Asking for the cash price reveals the true system cost. If the installer refuses to give a cash price, that is a red flag.

Some contracts include a price escalation clause that allows the installer to increase the price if equipment costs rise or if permit fees change. Look for a clause that says 'price guaranteed for [X] days' and confirm it covers the full period until installation. A reputable installer should guarantee the price for at least 30–60 days after signing.

Ask the installer to explain how their pricing compares to the average in your state. Use the Quote Review Tool to check the price per watt against local benchmarks independently. If the installer claims their price is 'below market' but the Quote Review says it is high, trust the data.

The equipment questions cover panel quality, inverter type, warranty coverage, and certification. These determine how long your system lasts and what support you get if something fails.

The contract should list exact makes and models, not just brand names or generic categories. Ask for the model numbers. Then research the manufacturer warranty: tier-1 panel manufacturers (REC, Qcells, Silfab, SunPower/Maxeon, LONGi) typically offer 25-year product and power warranties. Some lesser-known brands offer shorter coverage. Inverter type matters — microinverters (Enphase) carry a 25-year warranty; string inverters (SolarEdge, SMA) are 10–12 years.

This covers labor if the installation fails. SEIA recommends a minimum 10-year workmanship warranty. If the installer offers 1 or 2 years, consider it a red flag. Confirm what the workmanship warranty covers (roof leaks, electrical faults, racking failure) and whether it is transferable if you sell your home.

Some installers handle warranty claims on your behalf. Others require you to contact the manufacturer directly. Ask: if a panel fails in year 8, who do I call? Is there a service fee for warranty claims? How long does a typical claim take to resolve? A local installer who services what they install is generally more responsive than one who subcontracted the work.

Solar panels last 30+ years. A roof typically lasts 20–30 years. There is a high probability you will need to re-roof during the system's lifetime. Ask: how much does it cost to remove and reinstall the panels for a roof replacement? Some installers include one free re-roofing service in the contract. If not, budget $3,000–$6,000 for removal and reinstallation.

All grid-connected solar equipment should carry UL listing (UL 1703 for panels, UL 1741 for inverters) or an equivalent certification. This is required for utility interconnection and insurance. Ask the installer to confirm the equipment is UL-listed or equivalent.

Financing is where most of the confusion and hidden costs live. These questions help you understand the true cost of a loan versus a lease versus a PPA.

Some installers present loans as if they were leases ('no money down, fixed monthly payment'). Ask directly: will I own the system after the loan is paid, or does a third party own it? If it is a loan, ask: what is the APR? What are the dealer fees? Is it a secured loan (UCC lien on your home)? If it is a lease, ask: what is the annual escalator? How does the buyout work?

Dealer fees are the single biggest hidden cost in solar loans. An installer may offer a 'zero-down, 3.99% APR' loan — but that rate comes with a 25–30% dealer fee added to your principal. Ask: what is the total loan amount including all fees? Compare that to the cash price. The difference is your dealer fee.

Some solar loans have prepayment penalties, especially in the first few years. Ask: is there a penalty for early payoff? If so, how much and for how long? Also ask whether the loan is a simple-interest or pre-computed loan — pre-computed loans charge all interest upfront regardless of early payoff.

Many lease and PPA contracts include an annual escalator clause that raises your payment by 1–3% every year. A 2% escalator on a $200/month lease means you will pay $244/month in year 10 and $298/month in year 20. Ask: what is the escalator rate? Is it fixed or tied to an index? What will my monthly payment be in years 5, 10, 15, and 20?

The installation phase questions help you understand timelines, subcontractor usage, and what to expect during the actual install.

Some solar companies use their own trained crews. Others subcontract installation to third parties. If subcontractors are used, their quality and warranty coverage may differ. Ask: who specifically will be on my roof? Are they employees or subcontractors? Does the warranty cover subcontractor work? Can I see examples of their recent installs in my area?

A typical solar installation takes 4–8 weeks from contract signing to interconnection: 1–2 weeks for permits, 1–3 days for installation, 2–4 weeks for utility approval and interconnection. Ask for a specific timeline with milestones. Ask what happens if the utility delays interconnection — who is responsible for follow-up?

Many HOAs require approval for solar installations (though the Solar Rights Act limits their ability to deny). Some utilities have specific interconnection application processes. Confirm the installer handles all of this, and ask whether there are additional fees for these services.

Installer production estimates are not guarantees unless the contract says otherwise. Ask: what is your estimated annual production, and how was it calculated (PVWatts, Aurora, Helioscope)? What is your accuracy track record — have your estimates typically been within 10% of actual production? For leases and PPAs, ask about the production guarantee (coverage and compensation).

These questions cover what happens after your system is turned on — monitoring, service, and long-term reliability.

Ask: does the system include monitoring (app or web portal)? Is monitoring included in the price or is there a monthly subscription fee after the first year? Can I set up alerts for underperformance? What data can I see (kWh production, panel-level vs. system-level, battery status)? For leases, can I see the monitoring data even though the provider owns the system?

Ask: if the system stops working or an error appears on the monitoring app, who do I contact? What is the typical response time for service calls? Is phone and email support included, or is there a premium support option? What is your track record with post-installation support — can you provide references from customers who have needed service in years 2–5?