Many people searching for "solar panel installers" near them are confused about which type of installer they need — commercial or residential. The two disciplines are genuinely different, requiring different certifications, grid connection processes, tax structuring, and warranty cover. This page explains the differences, who needs which, and how to find the right installer for your specific project. We are commercial-only solar specialists (warehouses, factories, distribution centres, retail, hotels) — for residential and small business work we recommend specialist domestic installers via the MCS database.
Residential vs commercial solar — the five key differences
Five fundamental differences between residential and commercial solar in the UK. (1) MCS Certification: Residential = MCS Domestic, Commercial = MCS Commercial. Different audit and training requirements. (2) Grid Connection: Residential under 11 kW = G98 installer notification (no DNO pre-approval). Commercial above 11 kW = G99 with formal DNO technical study and connection offer (13-18 weeks typically). (3) Tax Structuring: Residential = Smart Export Guarantee (SEG) export tariff only, no capital allowance. Commercial = 100% Annual Investment Allowance up to £1m capex, Freeport/EZ Enhanced Capital Allowances, IETF/UKSPF grants. (4) Structural Engineering: Residential = permitted development, installer sign-off sufficient. Commercial = Chartered Structural Engineer certification mandatory for Insurance-backed Warranty cover. (5) Warranty: Residential = manufacturer warranties (panels 25yr, inverter 10yr). Commercial = additional Insurance-backed Warranty (IWA) covering 10-year design and workmanship if contractor ceases trading.
Who needs commercial solar — and who needs residential
Use this checklist to identify the right type of installer. Commercial solar (>11 kW, MCS Commercial required): warehouses, factories, distribution centres, cold storage, manufacturing facilities, large retail premises, hotels, restaurants, offices, schools, hospitals, churches, agricultural buildings, car parks (with EV charging or canopies). Residential solar (<11 kW, MCS Domestic): houses, flats, small home extensions, garden offices, small allotment buildings, residential annexes. Border cases (<25 kW): small B&Bs, small offices, small commercial buildings — can go either way but Commercial certification typically better positioned for tax structuring and growth. We refuse residential work — it requires different team skills, different supply chain, different supply economics.
How to find a residential solar installer in your area
For residential solar (homes, flats, garden offices, small extensions), use the official MCS database to find MCS Domestic certified installers in your area. Visit mcscertified.com and search by postcode. Look for installers with: (1) MCS Domestic certification (not Commercial). (2) Energy Performance Certificate (EPC) issuing capability. (3) Smart Export Guarantee (SEG) tariff registration. (4) Domestic warranty cover (Renewable Energy Consumer Code, RECC). (5) Local presence — residential solar requires multiple site visits during commissioning. We do not deliver residential work and cannot recommend specific residential installers, but the MCS database is the standard verification route. Also consider the Trustpilot ratings and Renewable Energy Consumer Code (RECC) membership.
How to find a commercial solar installer in your area
For commercial solar (warehouse, factory, distribution centre, large retail, hotel, office above 25 kW), evaluate against eight criteria. (1) MCS Commercial certification: verify on the MCS database (mcscertified.com). (2) Commercial track record: 5+ projects above 100 kW in last 24 months. (3) DNO G99 engineering relationships with your local DNO (UKPN, WPD/NGED, SSEN, Northern Powergrid, ENW, SP Energy Networks). (4) Insurance-backed Warranty (IWA) cover. (5) Chartered Structural Engineer in-house or partnered. (6) IETF / UKSPF / Enterprise Zone ECA grant application experience. (7) Customer Scope 3 audit pack capability. (8) Portfolio rollout capability for multi-site operators. We meet all 8 criteria with 500+ UK commercial installations since 2010 across all warehouse sub-sectors.
Why we are commercial-only — and what that means for you
We deliberately decline residential work. Three reasons. (1) Different supply chain: residential installers buy smaller panel quantities at higher per-unit prices, source from different distributors, and use different mounting kits. Mixing residential and commercial in one business reduces commercial-side competitiveness. (2) Different project rhythms: residential solar is small project, fast turnaround (4-8 weeks total), local installer model. Commercial is large project, long timeline (8-14 months), engineering-led project management. The skill sets are different. (3) Customer expectations: residential customers want phone-call accessibility and quick fixes. Commercial customers want engineering rigour, formal documentation, and managed projects. Trying to serve both compromises both. For warehouse, factory, distribution centre, cold storage, retail, hotel and office solar — we are highly specialised and deliver consistently. For homes, we recommend MCS Domestic installers.
Common questions about commercial vs residential
Do you install solar panels on homes?
No — we are commercial-only solar specialists. We install on warehouses, factories, distribution centres, cold storage, retail premises, hotels and offices (typically systems above 25 kW). For homes, flats, garden offices and small residential buildings, use the MCS database (mcscertified.com) to find MCS Domestic certified installers in your area.
What is the difference between commercial and residential solar?
Five key differences. (1) MCS Commercial vs MCS Domestic certification. (2) G99 vs G98 grid connection process. (3) 100% AIA tax relief vs SEG export only. (4) Chartered Structural Engineer required for commercial. (5) Insurance-backed Warranty cover for commercial. Commercial systems are typically larger (25 kW to 5 MW+), more complex, longer timelines (8-14 months), and require different installer skill sets.
Can a residential installer do commercial solar?
Generally not effectively. Commercial solar requires MCS Commercial certification, G99 engineering experience with local DNO, Chartered Structural Engineer partnership, Insurance-backed Warranty cover, and customer Scope 3 audit pack capability. Residential installers attempting commercial work typically struggle with the longer G99 timelines, grant applications, and structural engineering requirements. Use commercial-only specialists for projects above 25 kW.
What size solar system needs commercial certification?
UK rules require MCS Commercial certification (not Domestic) for any system above 11 kW or any system on a commercial building. In practice this means any warehouse, factory, distribution centre, retail premises, office or hotel install needs commercial — even a small 15-25 kW system. Homes are typically under 11 kW and use Domestic.
Why are commercial and residential solar prices so different?
Per-kW costs are actually similar (£800-£1,000/kW for small commercial vs £1,000-£1,400/kW for residential). The total cost difference is due to system size — residential 4-6 kW systems cost £4,000-£8,000 total; commercial 250 kW-3 MW systems cost £200,000-£3,000,000 total. Commercial benefits from scale economics in panels, inverters, and DNO connection costs.
Can I install commercial solar on my farm/agricultural building?
Yes — agricultural buildings (barns, sheds, storage units, processing facilities) are typical commercial solar installations. Treated as commercial for MCS certification, G99 grid connection, and AIA tax relief. Farm buildings often have excellent roof area, agricultural irradiance, and IETF/agricultural grant eligibility. We deliver farm building solar as part of our commercial portfolio.