# How to choose a commercial solar provider: accreditations, questions and red flags

Check accreditations such as MCS and NICEIC, review references and recent commercial installs, and read the warranty terms on panels, inverters and workmanship. Ask how the system was sized, who handles the DNO connection, and what happens if performance falls short. Treat vague guarantees and pressure selling as warning signs.

## Which accreditations should a commercial installer hold?

For commercial solar, look for recognised accreditations rather than claims alone. MCS certification covers the quality of design and installation and is often needed for some incentives; NICEIC or NAPIT registration shows the electrical work is independently assessed. Membership of a trade body such as RECC adds a consumer-standards layer.

Ask to see the certificates and check they are current and cover commercial-scale work, not only domestic. An installer comfortable evidencing their credentials is a good early sign. Confirm which accreditations are relevant to your project with the provider, as requirements differ by scheme and system size.

## What questions should I ask before signing?

Useful questions go beyond price. Ask how they sized the system, and whether it was based on your actual half-hourly consumption or a rough estimate. Ask who manages the DNO connection application (G99 or G98), what monitoring you will get, and how aftercare and maintenance are handled once the system is live.

On the commercial terms, read the warranties carefully. Panels, inverters and workmanship usually carry different lengths of cover, and a performance warranty should state what output is guaranteed and what remedy applies if it is not met. If a funded route is offered, get the per-kWh rate, term and end-of-term position in writing.

## What are the red flags?

Some patterns should give pause. Pressure to sign quickly, reluctance to provide references or certificates, quotes with no clear system size or yield assumptions, and headline savings figures with no workings behind them all warrant more questions. Deposits that feel disproportionate, or a company with no traceable trading history, are worth checking too.

Ask for two or three recent commercial references and, if you can, speak to those sites about how the install went and whether output matched the projection. A credible provider expects this level of due diligence and will not rush you into a decision.

## Frequently asked questions

**What accreditations matter most for commercial solar?**

MCS for design and installation quality, and NICEIC or NAPIT for the electrical work, are the common ones to check, along with trade-body membership such as RECC. Ask to see current certificates that cover commercial-scale projects, not just domestic installations.

**How can I tell if a solar quote is realistic?**

A credible quote states the system size in kWp, the assumed annual output, and the consumption data behind any savings figure. If those workings are missing, or the savings look far higher than the numbers support, ask the provider to show how they were calculated.

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Source: [How to choose a commercial solar provider: accreditations, questions and red flags](https://ppafunding.com/guides/how-to-choose-a-commercial-solar-provider) · Author: PPA Funding team · Updated: 2026-08-03

PPA Funding is an independent introducer operated by DVC Group Ltd (Companies House 10462808), Shrewsbury — not the funder, the installer or the maintenance provider. The service is free to use; a commission may be earned from a partner at no extra cost. Content is educational and is not financial or tax advice.