Imagine you've just signed a solar contract. The sales visit made installation sound quick, so you cleared a weekend. The crew arrives, the panels go up, and by Friday afternoon the roof looks finished. But the system is switched off, and nobody can tell you when it will turn on.
Here is the short answer: solar panel installation is five stages in a fixed order: a site survey and design, permits and utility paperwork, the physical installation, an inspection, and the utility's permission to switch on. The roof work is usually the shortest stage, often a few days. Most of the calendar goes to approvals, which is why the panels can sit on your roof for a while before they produce usable power.
This guide walks through each stage in order: what happens, who does it, what you will see at home, and where projects tend to stall. You will also find a quick tool to point you to the right section, a few imagined scenarios, and a list of questions worth asking before you sign.
Key takeaways
- The order matters. Survey and design come first, then approvals, then installation, inspection, and finally permission to operate.
- Installation day is not the finish line. The system usually should not be switched on until inspection and utility approval are complete, where those are required.
- Your roof and electrical panel shape the project as much as the panels do. Problems found at the survey are cheap to fix. Problems found on install day are not.
- Timelines vary widely by country, utility, and local authority. Treat any promised date as an estimate and ask what it depends on.
Try it: where are you in the process?
Pick the statement that fits you best. The tool will point you to the part of this guide that matters most right now. It stores nothing and sends nothing anywhere.
The five gates every installation passes through
It helps to picture the project as five gates. Nothing moves to the next gate until the current one is open. This is also why a project can look finished and still be waiting.
| Gate | What happens | What you see at home |
|---|---|---|
| 1. Survey and design | The installer checks the roof, shading, structure and electrical panel, then designs the layout and sizes the system. | A site visit, then a proposal with drawings. |
| 2. Approvals | Permit and grid-connection applications are prepared and submitted. | Forms, signatures, and waiting. |
| 3. Installation | Mounting hardware, panels, wiring, and inverter are installed. | A crew on site, usually for a few days. |
| 4. Inspection | The local authority or an accredited inspector checks the work, where required. | A short visit, sometimes followed by a fix list. |
| 5. Permission to operate | The utility approves the connection and, if needed, updates the meter. | Often nothing visible: an email, a letter, maybe a meter change. |
Terminology differs by region. "Permission to operate" is sometimes called interconnection approval or grid-connection approval, and some places combine or skip certain gates for small systems. Ask your installer which ones apply where you live.
Why most people are surprised by the process
Most people go through the same three missteps, and each one is understandable.
- They compare quotes by headline price only. Two quotes can look similar and still differ in roof assessment, equipment, who handles permits, and what happens if the roof needs work.
- They treat installation day as the whole project. The visible work is the shortest stage. Surveys, design, and approvals happen out of sight.
- They assume the survey is a formality. The survey is where hidden problems surface, such as a tired roof, shading, or an electrical panel that needs upgrading. Finding them early is far cheaper than finding them mid-install.
The fix is to see the project as a pipeline rather than an event. With that picture in mind, here is each stage in detail.
The step-by-step process
Step 1: Decide what the system is for
Before anyone climbs a ladder, the project starts with a goal. Common ones are cutting electricity bills, covering most of your usage, adding battery backup, or preparing for an electric vehicle or heat pump. The goal drives the size of the system and the equipment, so say it clearly. Have recent electricity bills ready, since they show how much you use and when.
Step 2: The site survey
The survey answers one question: can this property host a system that meets your goal? A thorough survey usually covers:
- Roof condition and age. Panels typically stay for many years, so a roof near the end of its life is a planning issue.
- Roof structure. Mounting hardware needs to fix into solid structure, so the installer checks rafters or purlins and the framing's condition.
- Orientation, tilt, and shading. Trees, chimneys, neighboring buildings, and even vents can reduce output at certain hours or seasons.
- The main electrical panel. Its capacity, condition, and available space affect how the system connects.
- Cable routes and equipment locations. Where the inverter and any battery will sit, and how wiring will get from roof to panel.
Some companies do part of this remotely with satellite images or drone photos. That can work for a first pass, but ask whether someone will physically verify the roof and electrical panel before the design is final.
Step 3: System design
With survey data in hand, the installer designs the layout and chooses the main components. The key decision is how the panels' direct current (DC) electricity gets converted into the alternating current (AC) your home uses:
- String inverter: one central inverter serves a group (string) of panels. It is simple and often cost-effective, but shading on one panel can affect the others in its string.
- Microinverters: a small inverter sits behind each panel. Panels work more independently, which can suit roofs with partial shade or multiple orientations, at a different cost and complexity.
- Power optimizers with a central inverter: a middle path, with panel-level electronics plus one main inverter.
None of these is best for every roof. The right question for your installer is "why this choice for my roof?" The answer should refer to your shading, layout, and budget, not only to what they usually install.
You should come away with a design that shows panel positions, the equipment list, and an estimate of yearly production. Treat production estimates as estimates, since weather and shading vary from year to year.
Step 4: Permits and utility approval
This stage is mostly invisible and is where many delays occur. Typically it involves:
- Building or electrical permits from the local authority, where required, based on the design drawings.
- A grid-connection application to your electricity utility, which usually needs to approve the system before it can run connected to the grid.
- Any property-specific approvals, such as homeowner association or building-owner consent, where they apply.
Ask your installer who submits these, how they track them, and what happens if the authority asks for changes. Also confirm whether your contract includes this paperwork or whether it is extra.
Step 5: Preparing for installation day
Once approvals are in place or clearly on track, equipment is ordered and a date is scheduled. Before the crew arrives, confirm:
- Access to the roof, the electrical panel, and the planned inverter location.
- How power will be interrupted during the work, and for roughly how long.
- Where materials will be stored, and where the crew may park.
- What happens if rain or wind pushes the date back.
Step 6: Installation day
The work is physical but follows a predictable order. For a typical home system, a crew usually needs a few days, sometimes less for a small system and more for a large or complex roof. In general, you can expect:
- Safety setup. Fall protection, ladders or scaffolding, and a plan for protecting the roof surface.
- Roof attachments. Mounting points are located over solid structure and fixed down. Where they pass through the roof, they are flashed or sealed to keep water out.
- Racking. Rails or frames are fixed to the attachments and aligned.
- Panels. Panels are clamped onto the racking and connected to each other.
- Wiring and grounding. Cables are routed and secured, and the system is bonded and grounded to the required standard.
- Inverter and electrical connection. The inverter is mounted, and the system is wired to your electrical panel, usually with dedicated protection devices and isolation switches. Some regions also require rapid-shutdown devices.
- Labeling and tidy-up. Required labels are fixed, debris is cleared, and the crew documents what was installed.
A note on safety: solar panels generate electricity whenever light hits them, so the DC wiring can carry voltage even when the house is switched off. Roof work and electrical connections are also hazardous. This is why most places require qualified, often licensed, installers and electricians for the work, and why DIY is a regulatory question as well as a technical one.
Step 7: Inspection
Where inspection is required, an inspector from the local authority or an accredited body checks that the installation matches the approved design and meets local electrical and building rules. If something fails, the installer corrects it and the inspection is repeated. A short fix list is common and usually not a sign of a bad installer. How the installer responds is the better signal.
Step 8: Permission to operate and switch-on
After a successful inspection, the paperwork goes to your utility. Once the utility approves, and the meter is updated if needed, you receive permission to turn the system on. Do not switch on a grid-connected system before you have that permission, because it may breach the rules or your contract. Your installer will tell you the exact point at which it is allowed.
When the system is switched on, it should be commissioned: the installer checks that it starts correctly, the inverter reports normal operation, and you can see data in the monitoring app, if the system includes one.
Step 9: After switch-on
Make sure you leave the project with the key documents: the final design, equipment list and serial numbers, warranty papers for panels, inverter, and workmanship, the permit and approval records, and instructions for monitoring and for shutting the system down safely. Warranty periods vary between manufacturers and installers, so read the actual documents and note who to call for each issue.
Maintenance is usually light, but it depends on your climate and roof. In dusty areas or under trees, panels may need occasional cleaning. Ask your installer what the manufacturer recommends and whether cleaning on a roof is something you should do yourself or leave to a professional.
Where the time actually goes
If you've signed and nothing seems to be happening, the system is probably in one of the quiet gates. From contract to switch-on, projects commonly take from several weeks to a few months, depending on your region, utility, and local authority. The physical work is a small slice of that, and the rest is usually one of these:
- Design and survey scheduling. Waiting for a site visit or a final design review.
- Permit review. Authorities have their own queues, and a request for changes restarts part of the clock.
- Equipment availability. Specific panels, inverters, or batteries can be delayed.
- Installer scheduling and weather. Crews book ahead, and rain or high wind can postpone roof work.
- Inspection booking. The system sits finished until an inspector is available.
- Utility approval. This is often the least predictable wait, because the installer does not control it.
A good installer can tell you which gate your project is at and who currently holds the next step. If you can't get a clear answer, treat that as information.
How mounting changes with the roof type
"Putting panels on a roof" means different things depending on what the roof is made of. This table shows the common approaches. Your installer's design may differ based on your structure and local rules.
| Roof type | Common mounting approach | What to ask about |
|---|---|---|
| Asphalt shingle | Flashed attachments fixed into the rafters, with rails on top. | Roof age, and how the crew makes sure fixings hit solid structure. |
| Clay or concrete tile | Hooks that sit under tiles, or replacement tiles with built-in mounts. | Breakage risk during work, and how damaged tiles are replaced. |
| Standing-seam metal | Clamps that grip the raised seams, often with no roof penetrations. | Clamp compatibility with your specific seam profile. |
| Corrugated or profiled metal | Brackets fixed through or onto the profile, with sealing. | Sealing method, fixing points, and long-term corrosion compatibility. |
| Flat roof | Weighted (ballasted) frames or tilted racks fixed down, depending on design. | Added weight, drainage, and effects on waterproofing warranties. |
Three imagined scenarios
The following are illustrative examples, not real cases. They show how common complications play out and what the sensible response usually looks like.
Illustrative scenario 1: The roof is nearly at the end of its life
Imagine a homeowner whose survey shows the roof covering is old and likely to need replacing within a few years. Installing panels now means removing and reinstalling them later, which adds labor cost. A common response is to replace or repair the roof first, then install. Another is to proceed with a clear written plan for who handles the panel removal and reinstallation, and how it will be priced, if the roof work comes sooner than expected. Ask for the roof assessment in writing.
Illustrative scenario 2: One corner of the roof is shaded
Imagine a roof where a tree or chimney shades part of the array for some hours of the day. The installer might leave that area empty, move panels elsewhere, or pick panel-level electronics so the shaded panels do not drag down the rest. Each option has trade-offs in cost and output. Ask to see how the design handles the shade, and whether the production estimate accounts for it.
Illustrative scenario 3: The electrical panel is old or full
Imagine a house where the main electrical panel has no space for the new connection, or does not meet current requirements. The installer may recommend an upgrade or a different connection approach. This changes the budget and sometimes the timeline, and it should be identified at the survey. If it appears for the first time on install day, ask why it was missed, and ask for the revised cost in writing before work continues.
Questions to ask before you sign
These questions help you compare installers on what shapes the outcome, not only on price. A clear, specific answer to each is a good sign. Vague answers are worth noting.
- Will someone physically inspect my roof and electrical panel before the design is final?
- Who prepares and submits permits and the utility application, and is that included in the price?
- What is the realistic timeline from signing to switch-on, and what does it depend on?
- Why did you choose this inverter type and layout for my roof?
- How will roof penetrations be sealed, and who is responsible if a leak appears later?
- What does the production estimate assume about shading and weather?
- What happens if the inspection fails, or if the utility asks for changes?
- Which warranties come with the equipment and the workmanship, and who do I call for each?
- What will I receive at handover, and how do I shut the system down in an emergency?
If you are comparing quotes, put the answers side by side. Differences in the answers often explain differences in the price.
Common mistakes and how to avoid them
- Switching on before approval. Wait for the installer's confirmation that you have permission to operate.
- Choosing on price alone. Compare scope: survey depth, paperwork, equipment, and warranty handling.
- Ignoring roof age. Ask for an honest roof assessment, in writing, before design is finalized.
- Accepting vague timelines. Ask which gate the project is at and who owns the next step.
- Skipping the handover documents. Without serial numbers, drawings, and warranty papers, future claims get harder.
- Assuming the system works during a power cut. Most grid-connected systems shut down during an outage for safety. Backup needs specific equipment (see the FAQ below).
Frequently asked questions
Do I need a new roof before installing solar panels?
Not always. It depends on the roof's condition and expected remaining life. If the roof will likely need replacing while the panels are on it, doing the roof first is usually simpler and cheaper than removing and refitting the array later. Ask your installer for a roof assessment.
Will my panels keep working during a power cut?
Usually not, if the system is connected to the grid. Standard grid-connected inverters shut down during an outage so that they do not feed power into lines that workers may be repairing. To keep power during an outage, you generally need a battery and an inverter set up for backup operation. Ask about this at the design stage, since it changes the equipment and cost.
Can I install solar panels myself?
The answer depends on local law, your utility, and your equipment's warranty terms. In many places, grid-connected work must be done or signed off by a qualified electrician or certified installer. The work also involves roof access and live electrical hazards. Check your local authority's rules before considering it, and do not treat this guide as electrical advice.
Will the installation damage my roof?
Done properly, roof attachments are fixed into solid structure and sealed or flashed, and a well-installed system should not cause leaks. Problems usually trace back to poor sealing, missed structural fixings, or an already deteriorating roof. Ask how penetrations are sealed and who is responsible for roof-related issues, and get that in writing.
The takeaway
Back to that Friday afternoon, with a roof full of dark panels and nothing switched on. Nothing had gone wrong. The project was simply waiting at a gate that the sales conversation never mentioned: inspection, or the utility's approval. Once you see installation as five gates, survey and design, approvals, installation, inspection, and permission to operate, the waiting makes sense, and you know what to ask.
A sensible next step is to write down your top three questions from the list above and take them to your next installer conversation. Compare the answers as carefully as you compare the prices.
This guide gives general information only. Rules, incentives, and technical requirements differ by country, region, and utility. For decisions about your own property, rely on a licensed installer, a qualified electrician, and your local authority and electricity provider.