Solar Installation Process: Complete Step-by-Step Guide

After watching dozens of solar installations over the years, I can tell you this: the process involves a lot more than just slapping panels on your roof. But once you understand what's happening at each step, you'll feel way more confident navigating it—and you'll know exactly when to push back if something seems off.

Installation Timeline Overview

The total time from signing a contract to generating power is typically 6-12 weeks. Here's where that time goes:

Step 1: Getting Quotes (1-2 Weeks)

Start by getting quotes from 3-5 different installers. This is crucial—prices can vary 20-30% for the exact same system.

What to Compare

• System size (kW) — Are they sizing to cover your usage?
• Equipment — Panels, inverter brand and model
• Price per watt — Total cost ÷ system watts
• Warranty — Workmanship warranty (installer) vs. equipment warranty
• Financing terms — If using a loan or lease
• Timeline — When can they start? When will you have power?

Types of Installers

• National companies (Sunrun, etc.) — Higher prices, but more resources
• Regional installers — Often best balance of price and service
• Local contractors — May have lowest prices; verify licensing and experience

Step 2: Site Assessment (1-2 Hours)

After you choose an installer, they'll schedule a site visit to inspect your property. This is when they verify everything and finalize your system design.

What They Check

• Roof condition — Age, material, structural integrity
• Roof measurements — Exact dimensions and angles
• Shading analysis — Trees, chimneys, neighboring buildings
• Electrical panel — Capacity, age, need for upgrade
• Attic access — For running conduit
• Utility meter — Location and type

Potential Issues Discovered

• Roof replacement needed — Should be done before solar
• Panel upgrade required — Older 100-amp panels may need 200-amp upgrade
• Significant shading — May reduce system size or require tree trimming
• HOA restrictions — Design may need approval

Step 3: Design & Permits (2-6 Weeks)

This is typically the longest phase. Your installer creates engineering drawings and submits them to your city/county for permit approval.

What Happens

1. System design — Engineers create layout showing panel placement
2. Structural analysis — Verify roof can support panels
3. Electrical design — Wiring diagrams, inverter placement
4. Permit application — Submitted to building department
5. Utility application — Submitted to your electric company
6. HOA approval — If applicable

Why It Takes So Long

Building departments are often understaffed. Solar permits are relatively new to many jurisdictions. Some cities have 2-week turnaround; others take 6+ weeks. Your installer should communicate expected timeline.

Step 4: Installation Day (1-3 Days)

Once permits are approved, installation is scheduled. For a typical residential system, expect 1-2 days of work.

Day-by-Day Breakdown

Day 1: Racking and Panels

• Crew arrives (usually 7-8 AM)
• Install racking system on roof
• Mount solar panels to racking
• Run DC wiring from panels
• Duration: 4-8 hours depending on system size

Day 2: Electrical (if needed)

• Install inverter (usually in garage or on wall)
• Connect to electrical panel
• Install monitoring system
• Install rapid shutdown device (code requirement)
• Duration: 3-6 hours

What to Expect

• Noise — Drilling, hammering, crew talking
• Power outage — Brief (1-2 hour) outage for electrical connection
• Vehicles — Trucks and equipment in driveway
• Crew size — Usually 3-5 workers

You don't need to be home, but someone should be available to answer questions and let the crew access necessary areas.

Step 5: Inspection (1-2 Weeks)

After installation, a city inspector must approve the work before you can turn on the system. Your installer schedules this.

What the Inspector Checks

• Work matches permitted plans
• Electrical connections are safe and to code
• Proper labels and warning signs installed
• Rapid shutdown device works correctly
• Panel attachments are secure

If Inspection Fails

Don't panic—minor issues are common. Your installer fixes the problem and reschedules. Common issues include labeling, minor code violations, or documentation problems.

Step 6: Power On (Permission to Operate)

The final step is utility interconnection—getting "Permission to Operate" (PTO) from your electric company.

What Happens

1. Installer submits inspection approval to utility
2. Utility schedules net meter installation (if needed)
3. Utility issues PTO approval
4. You can turn on your system!

Timeline Varies

Some utilities issue PTO within days of inspection. Others take 2-4 weeks. Large utilities like PG&E and SCE are notoriously slow. Your installer should manage this process.

Choosing an Installer

What to Look For

• Licensed and insured — Verify C-46 solar license (in CA) or equivalent
• Years in business — At least 3-5 years; warranties need backing
• Reviews — Check Google, Yelp, BBB, SolarReviews
• References — Ask for recent customer contacts
• Workmanship warranty — 10-25 years for installation work
• Communication — Are they responsive? Do they answer questions clearly?

Questions to Ask

• Who does the actual installation—your crew or subcontractors?
• What's your average timeline from contract to PTO?
• What happens if something goes wrong after installation?
• Can I see the system design before signing?
• What's included in the price, and what costs extra?

Installer Red Flags

Watch out for these warning signs:

• High-pressure sales tactics — "Sign today or lose this price"
• No site visit before quote — They're guessing at your situation
• Price seems too good to be true — It probably is
• Won't provide written contract — Verbal promises mean nothing
• Vague about equipment — Can't tell you exact panel/inverter models
• Pushy about specific financing — May get kickbacks from lenders
• No local office or presence — Hard to get service later
• Won't provide references — What are they hiding?