Choosing an installer at a glance
The short answers. Each links to the detail further down.
| Question | Short answer |
|---|---|
| What makes a good commercial installer? | Projects like yours, in-house design, a clear safety process and warranties in writing. What to look for |
| Which accreditations matter? | MCS, an electrical scheme such as NICEIC or NAPIT, a health and safety scheme such as CHAS, and insurance. Checks |
| Local or national? | Neither is better by default. Match their experience to your project, and check how faults will be covered. Types of installer |
| How many quotes should I get? | Three is usually enough to see a fair price and more than one design. |
| How do I compare quotes? | On the same system size, equipment, assumptions and warranties, not on the headline price. Comparing quotes |
| What does PowerPilot check? | The MCS register, insurance, the Companies House record and reviews. How we work |
How PowerPilot helps you compare installers
PowerPilot is a free comparison service. We introduce your business to up to three vetted installers; they survey, design and quote, and you choose.
Tell us about your site
Your business name, the type of site and your electricity bill, then your contact details. It takes about two minutes.
Your part: a rough idea of your bill and whether the panels would go on a roof or on land.
We match up to three installers
Installers who are MCS-certified, insured and cover your area, chosen for the kind of site you have. Your details go to no more than three.
They survey and quote; you choose
Each installer calls, surveys the site (in person or from drawings and maps) and sends a proposal. Your contract, payments and warranties are with the installer you choose.
Your part: site access, 12 months of bills and time to compare the proposals.
Types of commercial solar installer
You'll come across three broad kinds of firm. Choose on how closely their experience matches your project.
| Type | Best for | Check |
|---|---|---|
| Local specialist | Rooftops up to a few hundred kWp, where a quick response matters | Whether they have the capacity for your size of job, and who does the design |
| Regional or national installer | Large roofs, ground-mounted arrays and businesses with several sites | Who will actually do the work, in-house teams or subcontractors, and fault response times |
| Electrical contractor offering solar | Sites that also want EV charging, a battery or a switchboard upgrade | How many commercial solar projects they've delivered, and of what size |
What to have ready before you ask for quotes
Installers can quote faster and more accurately with a few facts to hand. Approximate is fine; they'll confirm the detail at survey.
- 12 months of electricity bills
- Half-hourly data, if you have it
- Roof or land size and photos
- Operating hours
- Planned changes, such as EV charging
- Who owns the roof and the meter
Not sure solar suits your site yet? Commercial solar installation covers who it suits, what it costs and how long it takes.
What to look for when comparing installers
Signs of a strong installer
- Commercial projects like yours, with references you can call
- In-house design and one named project manager
- Handles the DNO grid application and says so in writing
- Explains yield, self-use and payback assumptions plainly
- Offers monitoring and a maintenance plan after handover
Red flags
- A vague quote with no equipment models or system size
- Payback claims with no assumptions shown
- No roof survey or structural check proposed
- Warranties promised verbally, not in writing
- Pressure to sign quickly
A strong regional installer is often a better choice than a weaker local one, especially for larger systems. What matters for maintenance is how quickly they'll respond to a fault, not how close their office is.
Accreditations, safety and warranties
Quick checks you can do yourself before you sign. Most take a minute on a public register.
| Check | What it tells you | How to check |
|---|---|---|
| MCS certification | The firm meets the standard for designing and installing solar PV. Smart Export Guarantee payments on systems up to 50 kW need an MCS-certified installation. | Search the MCS installer register |
| NICEIC or NAPIT | Their electrical work is assessed by a competent person scheme | Search the scheme's register |
| CHAS or another SSIP scheme | Their health and safety processes have been assessed | Ask for the certificate |
| Public liability insurance | Damage or injury during the works is covered | Ask for the certificate and the amount of cover |
| Companies House | The company is active, files accounts and how long it has traded | Search the company on Companies House |
| ISO 9001, 14001 or 45001 | Formal quality, environmental or safety management | Ask for the certificates; most useful on larger projects |
Warranties
There are two kinds, and you want both in writing:
- Product warranties cover the panels, inverters and mounting, and come from the manufacturer. Panels usually also carry a performance warranty that guarantees most of their output for 25 years or more.
- Workmanship warranties cover how the system was installed, and come from the installer. Lengths vary, so ask, and ask whether it is insurance-backed in case the installer stops trading.
Questions to ask every installer
Ask each installer the same questions, so you can compare their answers side by side.
- Which of your recent projects is most like ours, and can we speak to that client?
- Who designs the system, and who will be our point of contact during the work?
- Will you make the DNO grid application, and what happens if export is limited?
- What yield and self-use have you assumed, and why?
- Is the work done by your own team or by subcontractors?
- What warranties do you give, for how long, and are they insurance-backed?
- What monitoring and maintenance do you offer after handover, and at what cost?
- What is excluded from the price, and what do you need from us?
Comparing quotes like for like
Quotes for the same site can look very different. Line them up on the same points before you compare prices.
| A clear quote shows | Why it matters |
|---|---|
| System size (kWp) and layout | Price per kWp is the fairest way to compare cost |
| Panel, inverter and mounting makes and models | Equipment drives output, lifespan and warranties |
| Yield, self-use and export assumptions | Savings and payback depend on them entirely |
| Product and workmanship warranties | Shows who stands behind the system, and for how long |
| Exclusions and provisional sums | Roof repairs, grid upgrades and access often sit here |
| Timeline and payment stages | Avoid paying most of the price before work starts |
Prices differ mainly because of equipment choice, roof and electrical complexity, how much design and grid work is included, and whether monitoring and maintenance are part of the price. For typical prices per kWp and payback, see commercial solar panel cost.
You can buy outright, use asset finance or a lease, or let a third party fund the system under a Power Purchase Agreement. Each has different tax and accounting effects, so take independent advice. Tax reliefs and the few grants on offer are covered in solar panel grants for businesses.
What happens after you choose
The installer takes it from there: a detailed survey, the final design, the DNO grid application and any planning, then installation, testing and handover. Most commercial projects take 6–16 weeks from enquiry to switch-on, and most of that is waiting for approvals.
For every stage and what you'll need to do at each, see the installation process, step by step. On a farm? See solar panels for farms.
Frequently asked questions
How do I compare commercial solar installers fairly?
Ask each installer the same questions and get written proposals on the same scope. Compare system size, equipment, yield assumptions, warranties and exclusions before price, and speak to a client whose project was like yours.
What should a good commercial solar quote include?
The system size in kWp and layout, equipment makes and models, the yield and self-use assumptions behind the savings, product and workmanship warranties, exclusions and provisional sums, and the timeline and payment stages.
Do installers arrange planning permission and the DNO application?
Most commercial installers make the DNO grid application, and many will handle planning where it's needed. Confirm in writing which permissions they're responsible for and what they need from you.
How long does a commercial solar project take?
Usually 6–16 weeks from enquiry to switch-on. The survey and design are quick; the DNO application and any planning take longest. The work on site often takes days to a few weeks.
What checks should I do before signing a contract?
Check MCS certification on the MCS register, an electrical scheme such as NICEIC or NAPIT, a health and safety scheme such as CHAS, public liability insurance and the company's Companies House record. Get warranties in writing and speak to a recent client.
How does PowerPilot choose which installers to introduce?
We match your site type and location with up to three installers who are MCS-certified, insured and cover your area. We check each installer's MCS registration, insurance and Companies House record, and monitor reviews. It's free for you.