How Long Does Commercial Solar Installation Take? The Complete Timeline
Most Gauteng business owners expect solar installation to be a drawn-out, disruptive affair. It isn't. A typical commercial solar project goes from your first phone call to generating power in 4-8 weeks total, with actual on-roof installation taking just 2-4 weeks.
But that timeline depends on several factors — your roof, your municipality, your financing choice, and how prepared you are before the process starts. This guide breaks down every phase so you know exactly what happens, how long each step takes, and what you can do to keep things moving.
Phase 1 — Site Assessment (1-2 Hours, One Visit)
Everything starts with a site visit. This is not a quick sales pitch or a phone-based estimate. A proper commercial solar assessment requires someone physically on your roof and in your electrical room.
What gets assessed:
- Roof structure — load-bearing capacity, orientation, angle, shading from nearby buildings or trees, and overall condition. Solar panels add roughly 12-14kg per square metre, which most commercial roofs handle without modification, but this must be confirmed.
- Electrical infrastructure — your distribution board, grid connection, existing generator setup, and cable routing options.
- Energy consumption — ideally based on 12 months of electricity bills, so we can understand your usage profile across seasons.
- Operational patterns — when you use the most power, what loads are critical, and whether your peak consumption aligns with peak solar production hours.
What you should prepare:
Gather 12 months of electricity bills before the assessment. The more data available, the more accurate your proposal will be. If you can provide access to your roof, your DB board, and 30-60 minutes of your time, the assessment covers everything needed to design your system.
Cost: Free. Obligation: None.
At Gentricity, if solar is not suitable for your facility, we will tell you directly and explain why. No one benefits from installing a system that does not perform. Book your free assessment here.
Phase 2 — Custom Proposal and System Design (5-7 Business Days)
Within a week of the site visit, you receive a comprehensive proposal built specifically for your facility. This is not a templated quote with generic numbers.
Your proposal includes:
- A detailed system design showing panel layout, inverter selection, and battery sizing if applicable
- Energy generation projections based on your roof orientation and Gauteng solar irradiance data
- A full financial analysis: projected monthly and annual savings, payback period, return on investment, and the impact of the Section 12B tax deduction
- A side-by-side financing comparison — outright purchase versus PPA versus asset finance — with numbers specific to your case
- A clear installation timeline with milestones
- Warranty and maintenance details
Every cost is included in the proposal: panels, inverters, mounting, cabling, installation labour, grid connection, and monitoring setup. No hidden line items appear later.
We walk you through the proposal in person or via video call and answer every question until you are completely clear on the numbers and the process.
Phase 3 — Decision and Financing (1-2 Weeks)
Once you have the proposal, you decide how to proceed. This phase varies the most in duration because it depends entirely on you and, if applicable, your finance provider.
If you purchase outright: This is the fastest path. You approve the quotation, sign off, and we move to engineering. This can happen in days.
If you finance the system: We submit your application to our finance partners. Approval typically takes 5-10 business days, depending on the lender and the completeness of your financial documentation.
If you choose a PPA: The PPA agreement process involves contract review and sign-off. Allow 1-2 weeks for legal review on both sides.
How to speed this up:
- Make your financing decision early. If you know you want asset finance, start gathering financial documents (management accounts, tax returns) before the proposal arrives.
- Involve your financial director or accountant from the start. The Section 12B tax benefit is often a deciding factor, and having your tax advisor confirm the numbers early prevents delays.
- If you need board approval, schedule it before the proposal is finalised so there is no waiting period after delivery.
There is no pressure to rush. Your proposal remains valid, and we are available for follow-up questions. But if you are motivated by a specific financial year-end to capture the Section 12B benefit, timing this phase is critical.
Phase 4 — Engineering, Approvals, and Procurement (1-2 Weeks)
Once you commit, the technical work begins. This phase runs largely in parallel — engineering, approvals, and procurement happen simultaneously to keep the timeline tight.
Engineering design includes:
- Detailed roof layout with exact panel positioning
- Structural engineering sign-off (if required for your roof type)
- Electrical single-line diagram
- Inverter and battery specification
- Monitoring system configuration
Approvals include:
- Municipal notification or application, where required by your local authority
- Eskom or municipal grid connection application
- Structural compliance documentation
Procurement:
All components are ordered from verified supply chains. Lead times for standard components (Tier 1 panels, major inverter brands) are typically 1-2 weeks. Specialised or larger systems may take slightly longer.
This phase typically completes in 1-2 weeks. Engineering and procurement run simultaneously, so they do not add up sequentially.
Phase 5 — On-Site Installation (1-4 Weeks)
This is the phase most people think of when they hear "installation timeline." The actual on-roof work is efficient and, for most businesses, causes minimal disruption.
Typical installation durations:
| System Size | Installation Time |
|---|---|
| 30-50 kWp | 1-2 weeks |
| 50-150 kWp | 2-3 weeks |
| 150 kWp+ | 3-4 weeks |
What happens during installation:
- Roof mounting structures are installed first
- Panels are mounted and wired
- Inverters and battery systems (if applicable) are installed in the designated electrical area
- All DC and AC cabling is run and connected
- Electrical connections to your distribution board are completed
Disruption to your operations: minimal. Most work happens on the roof and in the electrical room. We plan around your business schedule. If critical areas need a brief power interruption for the final grid connection (typically 1-2 hours), we schedule this during off-hours or a time that suits your operations.
All work meets SANS 10142 and NRS 097-2-3 standards.
Phase 6 — Commissioning and Go-Live (2-3 Days)
The final phase is quick but important. Commissioning ensures your system performs as designed before we hand it over.
What happens:
- The full system is tested and commissioned
- An electrical Certificate of Compliance (CoC) is issued
- Municipal or Eskom notification is completed
- A net meter is installed if feed-in is applicable in your municipality
- The real-time monitoring platform is configured, and you receive access via web and mobile app
- We walk you through the monitoring dashboard so you can track generation, consumption, and savings from day one
Documentation you receive at handover:
- CoC for the installation
- All warranties (panels, inverters, batteries)
- System manual and maintenance schedule
- Section 12B documentation for your tax advisor, including a detailed, itemised tax invoice and commissioning certificate with date
From this point, your system is generating power and reducing your electricity bill.
What Affects the Timeline (And How to Keep It Short)
Several factors can stretch or compress the 4-8 week window:
Things that slow the process down:
- Incomplete electricity bill data at assessment stage
- Delayed board or management approval
- Slow finance applications due to missing financial documents
- Municipal approval backlogs (varies by local authority)
- Roof repairs needed before installation can begin
- Custom or non-standard component requirements
Things that speed the process up:
- Having 12 months of electricity bills ready before the assessment
- Involving your financial director and tax advisor early
- Pre-approving the project at board level so the decision phase is fast
- Choosing a standard system design with readily available components
- Working with an installer who handles the full process — design, procurement, installation, and commissioning — under one roof
At Gentricity, we manage the entire process from first visit to system activation. You deal with one company and one point of contact throughout. That alone eliminates the coordination delays that plague multi-contractor projects. Learn more about how we work.
The Complete Timeline at a Glance
| Phase | Duration | What Happens |
|---|---|---|
| Site Assessment | 1 visit (1-2 hours) | Roof, electrical, and consumption evaluation |
| Custom Proposal | 5-7 business days | System design, financial analysis, financing comparison |
| Decision and Financing | 1-2 weeks | Approval, finance application, contract sign-off |
| Engineering and Procurement | 1-2 weeks | Detailed design, approvals, component ordering |
| Installation | 1-4 weeks | On-site physical installation |
| Commissioning | 2-3 days | Testing, grid connection, monitoring setup |
| Total | 4-8 weeks | Assessment to activation |
For a business spending R50,000 or more per month on electricity, every week of delay costs real money — especially with Eskom tariffs increasing at 10-15% annually. The sooner the process starts, the sooner you lock in lower energy costs.
Ready to Start the Clock?
The first step takes 30 seconds: get in touch. We will schedule a site visit, assess your facility, and deliver a detailed proposal within a week. From there, most businesses are generating solar power within 4-8 weeks.
Get Your Free Assessment — no cost, no obligation, no jargon. Just the numbers you need to make a decision.
Or call Albert directly: (083) 287 5986
Gentricity is a commercial solar specialist serving businesses across Gauteng. We handle the full process — assessment, design, financing, installation, and monitoring — so you deal with one company from start to finish. Learn more about our solutions.