Quick answer: a residential solar installation runs in nine stages: check your site, review your energy use, size the system, choose equipment and an installer, sign and survey, get permits and utility approval, install, pass inspection, and receive permission to switch on. The physical work on your roof is usually the shortest part, often one to a few days for a typical home system. Paperwork, permits and utility approval often take longer than the installation itself, and timelines vary widely by country, utility and installer.
This guide walks you through each stage in order. For every step you will see what to do, why it matters, the mistake people most often make, and how to tell you are done. Use it to prepare for quotes, ask better questions, and spot problems before they cost you money.
Last updated: October 2026.
What you need before you start
- Your electricity bills for the last 12 months (they show your yearly usage in kWh, the unit your utility bills you in).
- Basic facts about your roof: material, approximate age, and which direction each section faces.
- Permission to install: if you rent, share a building, or live in a managed community, you may need written approval from the owner or association.
- A rough idea of your goal: lower bills, backup power, or both. Backup power usually means adding a battery, which changes the design and cost.
Try it: installation readiness checklist
Tick everything that is already true for you. The tool counts your progress and points you to the step to work on next. It runs in your browser and stores nothing.
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Educational checklist only. It does not assess your home or give technical, financial or legal advice.
Step 1: Check whether your site suits solar
What to do: look at four things before you contact anyone.
- Roof direction and tilt. In the northern hemisphere, south-facing surfaces generally collect the most energy; in the southern hemisphere, north-facing ones do. East and west faces can still work well, and flat roofs use tilted mounting frames.
- Shade. Watch the roof at different times of day. Shade on even part of a panel can reduce the output of the panels wired with it, depending on the equipment used.
- Roof condition. Panels typically stay up for decades, so a roof that needs replacing soon is cheaper to fix before the panels go on, not after.
- Electrical panel. An old or full panel may need an upgrade to accept a new solar connection.
Why it matters: these four factors decide how much energy you can produce and whether surprise costs appear later.
Common mistake: judging shade at one hour of one day. Low winter sun casts longer shadows than summer sun.
You are done when you can describe your roof sections (direction, rough size, shade, age) in a few lines you could give an installer.
Step 2: Read your energy use
What to do: add up the kWh on your last 12 monthly bills to get your yearly usage. Note whether usage spikes in summer (air conditioning) or winter (heating).
Why it matters: system size is built from your yearly usage. Using a single month can oversize or undersize the system.
Pro tip: if you plan to add an electric vehicle, a heat pump or air conditioning soon, tell installers now so the design leaves room for it.
You are done when you have one number for yearly kWh and a note about any big changes coming.
Step 3: Size the system
What to do: estimate how many kilowatts (kW) of panels you need. The basic logic is yearly usage divided by the yearly energy one kW of panels makes in your location. That second figure depends on sunshine, tilt, shade and system losses, so a good installer will model it for your roof.
Illustrative example (not real data): if a household uses 6,000 kWh a year and a design is expected to produce 1,400 kWh per kW per year, the target is roughly 6,000 ÷ 1,400, or about 4.3 kW. In practice the final size is also limited by roof space, budget, and the rules of your utility on how much you may connect.
Common mistake: trying to cover 100% of usage by default. Some utilities pay little for exported energy, which can make a smaller system the better fit. Ask how your utility credits or pays for surplus energy before deciding.
You are done when you have a target size range and know your utility's rule for exported energy.
Step 4: Choose equipment and compare quotes
A system has panels, an inverter (the device that converts the panels' direct current into the alternating current your home uses), mounting hardware, wiring and safety devices. The biggest design choice is usually the inverter type.
| Inverter approach | Strengths | Trade-offs | Often suits |
|---|---|---|---|
| String inverter (one central unit) | Simple, usually lower cost, one device to service | Shade on one panel can affect others on the same string; single point of failure | Unshaded, simple roofs |
| String inverter + optimizers | Panel-level handling of shade, panel-level monitoring | More electronics on the roof, higher cost than plain string | Partial shade or mixed roof angles |
| Microinverters (one per panel) | Each panel works independently, easy to expand | Usually higher upfront cost; repairs happen on the roof | Complex roofs, planned expansion |
What to do: request at least three written quotes for the same target size so you can compare like with like. For each, check:
- Panel and inverter brand and model, with datasheets.
- Warranty terms: product warranty, performance warranty, and the installer's own workmanship warranty (who honors it if the company closes?).
- What is included: permits, utility application, electrical panel work, monitoring, and roof penetration sealing.
- Total price and payment schedule, and what happens if the design changes after the site survey.
- Licensing, insurance and local references you can verify yourself.
Common mistake: comparing price per kW only. A cheaper quote may leave out items another quote includes, or use components with weaker warranties.
You are done when you have a side-by-side comparison of at least three quotes with the same items listed for each.
Costs, incentives and financing rules change often and differ by place. Check current figures with official sources and your installers, and consider speaking with a qualified financial advisor for decisions about loans or leases. This guide is general information, not financial advice.
Step 5: Sign the contract and approve the design
What to do: before signing, read the contract for scope, equipment list, price, timeline, cancellation terms and warranty. After signing, the installer usually sends someone for a site survey: they inspect your roof structure and attic, photograph your electrical panel, and measure the roof. Then they produce a design with a panel layout and electrical diagram for you to approve.
Why it matters: the survey is where hidden problems appear, such as weak rafters, panel space limits, or more shade than expected. The design is what gets submitted for permits, so changes later cost time.
Pro tip: ask where the inverter, meter-side equipment and any cable runs will go. Those spots affect your daily life more than the panels do.
Common mistake: approving the layout without checking that it matches the equipment in your contract.
You are done when you hold a signed contract and an approved design that lists the exact equipment you agreed to.
Step 6: Handle permits and utility approval
What to do: in most places the installer prepares and submits two kinds of paperwork. Confirm they will do both, and ask for copies.
- Building and electrical permits from your local authority, showing the system will be built safely.
- Interconnection application to your electricity utility, asking to connect your system to the grid. Some utilities also require an approved agreement before you may switch on.
Why it matters: operating an unapproved system can violate local rules, void insurance coverage, and create safety risks for utility workers.
Common mistake: assuming the installer's date for physical work means you can switch on that day. Permission to operate is a separate approval.
You are done when permits are approved and your utility has accepted the connection application (or told you what remains).
Step 7: Follow installation day
Installers generally work through the same sequence. Knowing it helps you ask sensible questions.
- Setup and safety. Crew stage equipment, set up fall protection, and confirm the plan against the design.
- Roof attachments. They locate rafters and fix mounting points, sealing each roof penetration with flashing so water cannot get in. This is the step where roof leaks start if done poorly.
- Racking. Rails go onto the attachments to hold the panels in line.
- Panels. Panels are clamped to the rails and wired together.
- Inverter and electrical work. The inverter is mounted, cables are run to it, and it is connected to your electrical panel through the required protective devices and a disconnect switch. Grounding and safety shutdown features are installed to meet local code.
- Labels and walkthrough. Required warning labels are applied, and the crew should show you the shutdown procedure.
Pro tip: take photos of the finished roof, wiring and labels before the crew leaves. They are useful for warranty claims and future roof work.
Common mistake: leaving without asking how to shut the system down in an emergency.
You are done when the system is physically complete, tidy, labeled, and you know how to isolate it. Note that it normally stays switched off until approval comes through.
Step 8: Pass inspection and get permission to operate
What to do: where required, a local inspector checks that the installation matches the approved plans and meets electrical and structural rules. After that, your utility gives permission to operate and may swap or reconfigure your meter so it can record energy sent to the grid.
Why it matters: inspection and utility sign-off are your confirmation that the system is safe and legal to run.
Common mistake: switching on before approval because the system looks finished.
You are done when you have written permission to operate (or the equivalent in your area) and the system is energized.
Step 9: Monitor and maintain the system
What to do:
- Set up the monitoring app and note your typical production on a clear day, so you can recognize when something is off.
- Compare monthly production with what the installer predicted, allowing for weather.
- Keep panels reasonably clean following the manufacturer's guidance, and never clean them in a way that risks a fall.
- Keep your contract, datasheets, permits, approval letter and photos in one folder.
Common mistake: never opening the monitoring app. A tripped inverter can go unnoticed for weeks.
You are done when monitoring works on your phone and your documents are stored together.
Typical timeline at a glance
The ranges below are general patterns, not promises. Local permit offices, utility queues and weather change them a lot.
| Stage | Who drives it | Typical pace |
|---|---|---|
| Research, quotes, contract | You | Days to several weeks |
| Site survey and design | Installer | Days to a couple of weeks |
| Permits and utility application | Installer, authority, utility | Often the longest wait: weeks to a few months |
| Physical installation | Installer | Often one to a few days for a typical home system |
| Inspection and permission to operate | Inspector, utility | Days to several weeks |
Troubleshooting
The installation is finished but nothing is switched on
This is normal while you wait for inspection or utility approval. Ask your installer which approval is outstanding and who is chasing it. Request a written status update rather than relying on verbal reassurance.
Production is lower than the quote predicted
Compare like with like: weather, season and shade all matter. Check the monitoring app for fault messages, look for new shade (a grown tree, a new building), and ask the installer to review the data. Persistent gaps under normal conditions are a reason to request a service visit under your warranty.
A roof leak appears after installation
Contact the installer immediately in writing and photograph the area. Roof penetrations are the likely place to check. Check whether your installer's workmanship warranty and your roofer's warranty interact, since roof warranties may require approved installation methods.
The inverter shows an error or stops
Note the error code or message and check the manufacturer's guidance. Do not open equipment or touch wiring. Call the installer or manufacturer support, who can diagnose it safely.
Your bill did not drop as much as expected
Review how your utility credits exported energy, any fixed charges, and whether your usage changed. A solar system reduces the energy you buy, but fixed fees and exported-energy rates differ by utility.
Common questions
How long does the installation itself take?
For a typical home system, the work on the roof is often one to a few days. Larger or more complex roofs, battery additions and electrical panel upgrades add time. The approvals around it usually take much longer.
Will I have power during a grid outage?
Not automatically. Standard grid-connected systems shut down during an outage for safety reasons. Backup power usually requires a battery and compatible equipment, which you should discuss in Step 4.
Can I install panels myself?
Rules differ by place, and the grid connection and many electrical tasks typically require a licensed professional. Check your local regulations and utility requirements before considering any do-it-yourself work.
Your next step
Gather your last 12 electricity bills and tick off the readiness checklist. Once you can answer most of its questions, request three written quotes for the same target size and compare them using the list in Step 4.