Commercial vs domestic solar — why business rules are different
Most solar advice online is written for homeowners, and applying it to a business will mislead you. VAT, tax relief, consumption patterns, consumer protection and planning all work differently. Here's what actually changes.
Search for solar advice and you'll mostly find guidance written for households — the 0% VAT, the evening-battery sizing, the consumer-protection reassurances. Almost none of it transfers cleanly to a business decision, and some of it will actively mislead you. If you're buying solar for a company, here's everything that's different — and why it matters.
1. Scale and engineering
A typical home system is 3–5 kWp. A commercial system is usually 30 to 250+ kWp — ten to fifty times larger. That changes the engineering: three-phase electrics, a formal DNO grid-connection process, structural loading assessments, and a proper site survey. It's a different class of project, not a scaled-up house.
2. VAT: 0% for homes, 20% for you
This one trips up businesses constantly. Domestic solar installations carry 0% VAT (in place to 31 March 2027). That relief does not apply to commercial premises, which pay the standard 20% VAT. The saving grace is that VAT-registered businesses reclaim it through their normal VAT return — so for most it's a cash-flow timing issue, not a true cost. But if you read "solar is 0% VAT" and budget on that as a business, your numbers are wrong. (Detail in grants and funding.)
3. Capital allowances: a business-only win
Households get no tax deduction for solar. Businesses do: commercial solar qualifies for the Annual Investment Allowance, a 100% first-year deduction that's worth roughly a quarter of the system cost back in corporation tax. This is one of the biggest financial differences, and it's entirely on the commercial side of the ledger.
4. Consumption shape: businesses often win here
Homes consume most of their electricity in the evening — after work, when the solar day is over. That mismatch is why domestic advice leans so heavily on batteries. Many businesses are the opposite: they consume during the working day, exactly when the panels generate. That means commercial sites often achieve higher self-consumption — using more of their generation directly at the full retail rate — which materially improves the economics and changes the battery calculus. (See south-facing vs east-west and battery storage.)
5. Tariffs and demand charges
Households pay relatively simple flat or time-of-use tariffs. Commercial electricity contracts can include capacity and demand charges — costs based on your peak power draw, not just total energy. That opens up value levers (peak shaving with a battery) that don't exist for domestic users, and it means a business's savings calculation has more moving parts.
6. Consumer protection: it protects homeowners, not businesses
Domestic buyers are covered by consumer codes like RECC and by consumer law generally. As a business, you're typically not a "consumer" in the legal sense, so those protections largely don't apply to you — your safeguards have to be written into the commercial contract instead. This is a crucial, widely-missed distinction; we cover it in MCS vs RECC.
7. Planning
Domestic and commercial both benefit from permitted-development rights, but the specifics differ. For commercial rooftop, the old 1MW cap was removed in 2023, so most business rooftop solar now needs no planning application at all — subject to conditions. (See planning permission.)
8. The payback verdict
Domestic payback varies widely with usage and battery choices. Commercial payback is currently 7–9 years on a well-suited site, sometimes faster where daytime self-consumption is high — after which the system delivers for another 15+ years. The combination of scale, capital allowances, daytime usage and high commercial electricity prices is what makes the business case distinct.
The bottom line
Don't run a commercial solar decision on domestic rules of thumb. You don't get 0% VAT, but you do get capital allowances; you probably self-consume more; your tariff may reward a battery in ways a home's wouldn't; and the consumer protections you'd assume as a homeowner don't shield your company. Read business-specific guidance — which is exactly what the rest of this site is.
Start with the numbers for your building: run the calculator. Then the payback and grants and funding guides cover the money, and the Brief keeps you current.
General information, not tax or legal advice. Confirm specifics for your business with your accountant and solicitor.