A First-Solar Purchase Checklist You Can Actually Follow

Buying solar for the first time can feel like reading a menu in another language. This checklist breaks the process into four small phases so you always know what to do next. No pressure, no jargon dumps, just simple steps you can tick off at your own pace as you move from curious homeowner to confident solar owner.

Solar is one of those purchases where the hard part is not the panels themselves. It is the order of operations. You can lose weeks bouncing between sales pitches if you skip the prep work, or sign a contract that hides a clause you did not understand. A checklist fixes that. It gives you a quiet, repeatable path from “I am thinking about it” to “the system is on the roof and producing what was promised.”

The four phases below are the ones I wish someone had handed me the first time I helped a friend shop for a system. Each phase has a short explainer and a tight list of micro-items. Work through them in order, and you will avoid most of the rookie mistakes that turn a five-figure purchase into a long regret.

Phase 1: Before you talk to an installer

The biggest favor you can do yourself is to delay the first sales call by about two weeks. Use that time to gather facts about your own house. When you eventually do invite installers in, you will ask sharper questions and be much harder to upsell. Most of this phase costs nothing and can be done on a Saturday afternoon with a tape measure and your utility account login.

• Pull twelve months of electricity bills. Most utilities let you download a CSV from your online account. You want total kilowatt-hours per month, not just dollar amounts.
• Note your average daily usage. Divide annual kWh by 365. A typical US single-family home lands somewhere between 25 and 40 kWh per day.
• Walk your roof from the ground. Look for the south, southwest, and west faces. Note shading from trees, chimneys, vents, and neighboring buildings.
• Check the roof’s age and material. If your shingles are older than about 12 to 15 years, plan to reroof first. Removing panels later to replace a roof typically costs 1,500 to 4,000 USD.
• Find your main electrical panel. Photograph the label inside the door. Installers will ask for the amperage (often 100, 150, or 200 amps) and the manufacturer.
• Look up local incentives. Search your state energy office plus the DSIRE database. Write down expiration dates so you do not miss any.

Two more soft tasks belong in this phase. First, talk to anyone in your neighborhood who already has solar. Ask what they would change. Second, write down your goal in one sentence. “Cut my bill by at least 70 percent” is a useful goal. “Go fully off grid” is a different goal that needs batteries and a much bigger budget. Knowing which one you are pursuing keeps the rest of the process honest.

Phase 2: When you start getting quotes

Aim for three quotes from three different installers. Two is not enough to spot a high outlier, and four starts to eat your weekends. Mix one national brand with two local companies if you can. Local installers tend to be cheaper and more flexible, while national brands sometimes offer longer workmanship guarantees. The point is not to crown a winner before they visit. It is to see the same project priced three ways so you can ask, “why are you 30 percent more than the other quote?”

When the proposals come back, do not just compare the bottom-line price. Open each one to the equipment page and copy the model numbers into a spreadsheet side by side. You are looking for the four pieces that drive long-term value.

• Panel make, model, and wattage. Tier-1 panels from established manufacturers usually run 380 to 450 watts each in 2025 and 2026.
• Inverter type. String inverters are cheaper, microinverters perform better with partial shade, and DC optimizers sit in the middle.
• System size in kilowatts DC. A 7 to 10 kW system covers most US homes. Bigger is not automatically better if it exceeds your usage.
• Production estimate in kWh per year. This is the number you will check against reality once the system runs.
• Price per watt installed. US averages for 2025 sit roughly between 2.75 and 3.75 USD per watt before incentives.

If you want a deeper walk-through of every line item that shows up in those proposals, my guide to reading a solar installer quote goes section by section so nothing surprises you.

Phase 3: Reviewing the contract

The contract is where polite excitement meets legal reality. Read it twice, ideally on two different days, and never sign in the same meeting where it was handed to you. A reputable installer will not pressure you. If someone says the price is only good if you sign today, that is your cue to walk away. Real incentives have expiration dates measured in months, not hours.

Most residential solar contracts are between 8 and 20 pages. The clauses that matter most are the ones people skim past because they look standard.

A few specific numbers to anchor yourself. Panel warranties should be 25 years for performance and 12 to 25 years for product defects. Microinverters often carry 25-year warranties, string inverters typically 10 to 12 years. Workmanship warranties from the installer themselves are the most variable, ranging from 2 years on the low end to 25 on the high end. Longer is better, but only if the company is likely to still exist in two decades.

Phase 4: After installation

The day the system turns on is exciting, and it is also the day most homeowners stop paying attention. That is a small shame, because the first 90 days are when you catch the issues that are easiest to fix. Wiring errors, a panel that did not get registered to the monitoring app, a string that is producing 20 percent below its neighbors. All of those things are normal and all of them are correctable, but only if someone notices.

• Activate the monitoring app within the first week. Enphase, SolarEdge, and Tesla all have homeowner apps. Bookmark the daily production view.
• Compare actual output to the proposal’s annual estimate. Expect month-by-month variation, but a full year should land within 10 percent of the estimate.
• Save the permission to operate document. Your utility will send a PTO letter or email. This is what makes net metering official.
• File the federal tax credit paperwork. The Residential Clean Energy Credit (Form 5695) gets claimed in the tax year the system was placed in service.
• Keep a folder, paper or digital, with the contract, warranties, system schematic, and serial numbers. A future buyer of your home will want all of this.
• Schedule a one-year performance review. Reread the proposal alongside a full year of monitoring data. If production is more than 10 percent low, contact the installer in writing.

If something does feel off in those first months, do not panic and do not jump to a forum thread for a diagnosis. Email your installer with the specific data and ask for a written explanation. Most reputable companies will resolve early-life issues at no charge. Many of the horror stories you read online started with a small problem that the homeowner ignored for years, not with a faulty installation. To sidestep the most common patterns that derail first-time buyers, see my piece on five mistakes beginners make buying solar.

Used in order, these four phases turn a daunting purchase into a series of small, finishable tasks. You do not need to memorize every detail. You just need to know which phase you are in and what the next item on the list is. That alone puts you ahead of most first-time buyers.

Frequently asked questions

Read next in Solar Basics

If this guide was useful, these two neighbouring pieces will fill in the surrounding context:

• Choosing the Right Solar Inverter Without Overpaying
• Solar Panels Explained for Complete Beginners

Sources and further reading

For the underlying data behind the numbers in this guide, and for the standards, incentive programs, and safety rules referenced throughout, see:

• PV basics and system design (NREL / National Renewable Energy Laboratory)
• ENERGY STAR: solar and home energy
• Solar Energy Industries Association: solar industry data