The Solar Installation Process: Step-by-Step Timeline

Step 1: Site Assessment (Week 1–2)

After signing a contract, your installer will schedule a site assessment — either an in-person visit or a remote assessment using satellite imagery (increasingly common).

The assessor evaluates:

• Roof condition, age, and remaining lifespan
• Roof pitch, orientation (south/east/west), and usable square footage
• Shading from trees, chimneys, or neighboring structures
• Electrical panel capacity and location
• Attic access for wiring runs

If your roof needs repairs or your electrical panel needs upgrading, you'll be notified here. Addressing these before installation is strongly recommended to avoid delays mid-project.

Step 2: System Design (Week 2–3)

Based on the site assessment, your installer's engineering team designs the final system. This includes:

• Exact panel layout (number of panels and their placement on the roof)
• Inverter selection and placement
• Electrical diagrams for permitting
• Structural calculations (required by most jurisdictions)

You'll receive a final design for approval before permitting begins. This is your last chance to make changes without additional costs.

Step 3: Permitting and HOA Approval (Week 3–7)

Permitting is the phase that causes the most variability in timelines. Your installer submits your system design to your city or county building department for approval.

What Permits Are Required?

• Building permit — structural approval for roof-mounted equipment
• Electrical permit — approval for the wiring and inverter
• Utility interconnection application — approval to connect to the grid

How Long Does Permitting Take?

This varies widely by jurisdiction:

• Fast: Arizona, California (many cities), Texas — 1–2 weeks with online portals
• Average: Most US cities and counties — 2–4 weeks
• Slow: Some Northeast municipalities, HOA-governed communities — 4–8 weeks

HOA Approval

If your home is in an HOA, you may need architectural review approval. Under the Solar Rights Act, most states prohibit HOAs from outright banning solar — but they can impose reasonable aesthetic restrictions (panel color, placement). Budget 2–6 extra weeks if HOA approval is required.

Step 4: Installation Day (1–2 Days)

The actual installation is usually the fastest part of the process. A crew of 2–4 installers typically completes a standard residential system in one to two days.

What happens on installation day:

1. Mounting rails are secured to your roof rafters
2. Panels are attached to the rails and wired together
3. Inverter is mounted (usually in garage or utility room)
4. AC disconnect and production meter are installed near your main panel
5. System is wired to your electrical panel
6. Monitoring equipment is installed and configured

Your installer will not turn the system on after installation — that requires utility approval first. Don't be alarmed if your new panels sit dormant for a few weeks after install day.

Step 5: Inspection and Permission to Operate (Week 8–12)

After installation, two more approvals are needed before your system can produce power:

City/County Inspection

A building inspector visits to verify the installation matches the approved permit. This typically takes 1–3 weeks to schedule and passes in a single visit if the work was done correctly.

Utility Permission to Operate (PTO)

Your utility company inspects or remotely reviews the installation, installs a new bi-directional meter (for net metering), and issues Permission to Operate. This is the final step before you can turn on your system.

PTO timelines vary significantly by utility:

• Investor-owned utilities (PG&E, ConEd, FPL): 2–6 weeks
• Municipal utilities: 1–3 weeks
• Rural co-ops: 3–8 weeks (often the slowest)

Total Timeline Summary

To start your solar journey, use our Solar Calculator to estimate your cost and savings — it takes less than 2 minutes and gives you a real baseline before talking to any installer.