Solar installation looks like a contracting business and behaves like one with an unusually difficult cash cycle.
Equipment and labour are paid before or during installation. A meaningful share of the customer's payment arrives at completion, at inspection, or through a financing partner afterwards, and incentives arrive later still.
This covers how these businesses earn, the revenue models in use, when revenue should be recognised, how the main federal incentive and depreciation interact, the working capital pressure that follows, and the metrics worth watching.
Overview: How Solar Installation Businesses Generate Revenue
Solar installation businesses, whether residential, commercial, or utility-scale, have a distinctive financial profile shaped by project-based revenue, long sales cycles, complex incentive structures, and capital-intensive operations. This guide walks through the key financial characteristics of a solar business.
Equipment and labour are largely paid before or during installation, while a meaningful share of the customer's payment arrives at completion or through a financing partner afterwards. A business can be profitable on every job and short of cash throughout, and growth makes that worse.
Abhinav Gupta, CPA, CA, MBA · LinkedInRevenue Models in Solar
| Revenue Model | Description |
|---|---|
| Direct install / cash sale | Customer pays full system cost; company recognizes revenue on project completion |
| Loan-financed install | Third-party lender (GreenSky, Mosaic) finances customer; company receives cash at install |
| Lease / PPA | Company retains ownership of system; customer pays monthly (lease) or per-kWh (PPA) |
| Commercial EPC | Engineering, Procurement, Construction contract; large-scale commercial/industrial |
Revenue Recognition for Solar Projects
Revenue recognition depends on the contract type and how performance obligations are fulfilled. For most residential installers:
- Revenue is recognized upon substantial completion and customer sign-off (not at contract signing)
- Deposits collected upfront are recorded as deferred revenue (liability) until the project is complete
- Progress billing for large commercial projects: recognize revenue proportional to project completion (percentage-of-completion method)
Federal Investment Tax Credit (ITC)
The federal solar Investment Tax Credit is one of the most significant incentives in the industry. Under the Inflation Reduction Act:
- The ITC reduces the federal income tax liability dollar-for-dollar (not a deduction, a credit)
- Available to the system owner, homeowner for cash/loan deals, the solar company for leases/PPAs
- For commercial systems, there are bonus credit opportunities (domestic content, energy communities) that can increase the rate
- Customers who finance with a solar loan typically own the system and claim the ITC themselves
Accounting for the ITC (Company-Owned Systems / Lease/PPA Portfolio)
If your company owns the systems (lease/PPA model), you recognize the ITC as a reduction of tax expense in the year the system is placed in service. The credit generates a deferred tax asset if not fully utilized in Year 1.
MACRS Depreciation on Solar Assets
Solar energy property qualifies for 5-year MACRS depreciation for federal tax purposes, regardless of the actual useful life of the system (which is 25-30 years). This accelerated depreciation significantly front-loads tax deductions.
- Bonus depreciation (100% in Year 1) may also apply
- ITC basis reduction: if you claim the full ITC, you must reduce the depreciable basis by 50% of the credit claimed
- State depreciation may differ from federal, some states do not conform to bonus depreciation
State Incentives
Solar incentives vary dramatically by state. Common forms:
- Net metering credits (reduces utility bill; not direct cash to installer but affects customer ROI)
- State tax credits (California does not have one; other states like New York and Massachusetts do)
- SREC markets (Solar Renewable Energy Certificates): Maryland, New Jersey, Massachusetts, DC
- Property tax exemption on added home value from solar (many states)
- Sales tax exemption on equipment (many states)
Working Capital Dynamics
Solar businesses can have strained working capital even when they are profitable:
- Projects funded upfront: installers often pay suppliers before customer payment is received
- Permit and interconnection delays: a project ready to install can sit for weeks awaiting permits
- Loan funding: third-party lenders fund installers at milestone completion, creating a timing gap
- Payroll weekly, project revenue monthly: a mismatch that requires a working capital line of credit
Pro Tip: Use a project management system that tracks each deal from contract to cash. Knowing your pipeline by stage tells you your cash position 60-90 days ahead.
Key Financial Metrics for Solar Businesses
| Metric | What It Tells You |
|---|---|
| Revenue per watt ($/W) | Total project revenue divided by system size in watts; benchmark against market rate |
| Gross margin per project | Revenue less direct costs (equipment, labor, permits) per job |
| Cost per watt ($/W) | Total install cost / system size; track against industry benchmarks |
| Customer acquisition cost (CAC) | Total sales and marketing spend / number of installs |
| Revenue per sales rep | Productivity benchmark for the sales team |
| Backlog value | Signed contracts not yet installed; forward revenue visibility |
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Frequently Asked Questions
How do solar companies handle deferred revenue?
Deposits and progress payments received before project completion are recorded as deferred revenue (a liability). Revenue is recognized as milestones are achieved or upon substantial completion.
Can a solar installer use cash-basis accounting?
Small installers (under $25M average annual gross receipts) may use cash-basis accounting for tax purposes. But for management decisions, accrual-basis project accounting gives a much more accurate picture of where money is actually being made or lost.
What is the typical gross margin for a residential solar installer?
Industry benchmarks vary by market. Gross margins of 20-35% are common for residential installers; margins depend heavily on competitive market dynamics, equipment costs, and labor efficiency. Commercial/industrial projects may carry lower margins but larger volumes.
What makes cash flow difficult in this industry specifically?
The order of payments. Equipment and labour are largely paid before or during installation, while a meaningful share of the customer's payment arrives at completion, at inspection or through a financing partner afterwards. Incentives arrive later still. A business can be profitable on every job and short of cash throughout, and growth makes that worse rather than better because each new project starts with an outflow.
What should the accounting show that a simple profit figure will not?
Profitability by project, with labour and equipment allocated to the job that consumed them, and a schedule of what is billed against what is complete. Without the first you cannot tell good jobs from bad ones, since the average hides both. Without the second you cannot tell whether a healthy profit figure is supported by work actually done or by billing that has run ahead of it.
Written by
Abhinav Gupta, CPA, CA, MBA
Abhinav works with business owners across the US on industry-specific bookkeeping, from dental practices and restaurants to construction and e-commerce. He writes about what each trade's books actually need. Connect on LinkedIn
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