Commercial solar panel installers, UK-wide

MCS certified, NICEIC registered, DNO and G99 handled in-house. Rossair has been a UK building services contractor since 1973 - so the company that installs your array is the one that maintains it, and it will still be here when the warranty matters.

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Rossair is an MCS certified commercial solar panel installer working across the UK, with offices in Alton, London and Manchester. We are a building services contractor established in 1973 rather than a solar-only installer - which means DNO applications and G99 protection are handled in-house, and the same company maintains the system after handover.

Researching the technology, sizing and payback rather than the installer? See commercial solar PV systems. For installed references, see our commercial PV installations.

1973
Trading since
MCS
Certified installer
NICEIC
Electrical registration
In-house
DNO and G99 handling

How to choose a commercial solar installation company

Commercial solar has attracted a lot of new entrants. Some are excellent. Some were formed in the last three years and are selling 25-year warranties. Five questions separate them:

  • Are they MCS certified? Required for Smart Export Guarantee eligibility and most building warranties
  • Are they electrically registered - NICEIC or equivalent? A commercial PV install is primarily electrical work
  • Do they handle the DNO application and G99 protection themselves, or subcontract the longest-lead item in the project?
  • Will they maintain the system after handover, or does the relationship end at commissioning?
  • How long have they been trading? A 25-year warranty is worth what the company behind it is worth

Ask them of us too. We would rather answer them now than have you find the gaps in year three.

A building services contractor, not a solar-only installer

Most commercial solar installers only do solar. That is fine until the array interacts with everything else on the roof and in the electrical infrastructure - which it does, immediately.

Rossair has been maintaining UK commercial buildings since 1973: HVAC, mechanical, electrical and PPM across education, NHS, care, commercial and government estates. When we install solar on a building we already maintain, it goes onto an estate we understand, with one contractor accountable for the roof, the switchgear and the plant underneath it.

Same names, year after year. We show up. We do it properly. We send the paperwork.

Commercial solar panel installations across the UK

We install rooftop, ground-mount and solar carport systems nationally, from our offices in Alton, London and Manchester. Coverage is densest across the South Coast and Home Counties - Hampshire, Surrey, Sussex, Dorset and the Isle of Wight - and our maintenance contracts already run across UK-wide estates.

Every installation covers survey and structural assessment, electrical and system design, DNO application and G99 protection, MCS certified installation, testing and commissioning, and full handover documentation. Battery storage can be installed alongside - see solar battery storage.

At a glance

Rossair as your commercial solar installer

Service
Commercial solar panel installation, UK-wide
Established
1973 - building services contractor
Certification
MCS certified installer
Electrical registration
NICEIC registered
Grid connection
DNO application and G99 handled in-house
Wiring standard
BS 7671 (IET Wiring Regulations)
Installation types
Rooftop, ground-mount, solar carport
Modules
Tier-1 monocrystalline (BloombergNEF Tier-1 list)
Storage integration
Battery storage installed alongside or retrofitted
After handover
O&M and PPM contracts under the same contractor
Coverage
UK-wide; South Coast base - Hampshire, Surrey, Sussex, Dorset, IoW
Offices
Alton (HQ), London (Aldgate), Manchester
Frequently asked

Questions about commercial solar installation

What should I look for in a commercial solar panel installer?
Five things worth checking before anything else. MCS certification, which is required for Smart Export Guarantee eligibility and most building warranties. NICEIC or equivalent electrical registration, because a commercial PV installation is primarily electrical work. Whether the installer handles the DNO application and G99 protection in-house or subcontracts it. Whether they can maintain the system after handover, or disappear at commissioning. And how long they have been trading - a 25-year performance warranty is only as good as the company standing behind it.
Is Rossair an MCS certified commercial solar installer?
Yes. All Rossair solar PV installations are MCS certified, and we are NICEIC registered for electrical installation certification. MCS certification is required for systems up to 50 kW to qualify for the Smart Export Guarantee, and above that threshold it remains a meaningful quality signal for insurers and funders.
Do commercial solar installers handle the grid connection?
Some do, many subcontract it, and it is worth asking directly. Commercial systems above 3.68 kW per phase need DNO approval - a G98 notification for the smallest installations, a G99 application for commercial scale. The application confirms available export capacity and any network reinforcement the site must fund, and it is frequently the longest-lead item in the whole project. Rossair handles G99 applications, witness testing and energisation in-house.
Which areas of the UK does Rossair cover?
We install commercial solar across the UK, with offices in Alton (Hampshire HQ), London (Aldgate) and Manchester. Our densest coverage is the South Coast and Home Counties - Hampshire, Surrey, Sussex, Dorset and the Isle of Wight - but we deliver nationally, and our maintenance contracts already run across UK-wide estates.
Can one contractor install solar and maintain the rest of the building?
That is the case for using a building services contractor rather than a solar-only installer. Rossair has been maintaining UK commercial buildings since 1973 - HVAC, mechanical, electrical and PPM. Adding solar to an estate we already maintain means one contractor, one point of accountability and one set of records, rather than a separate supplier who knows the roof but not the building.
How disruptive is a commercial solar installation?
Rooftop installations can usually proceed with minimal impact on occupants, working to agreed access routes and hours. The disruptive moments are electrical connection points, which require planned shutdowns - these are scheduled in advance and normally taken outside operating hours. Estates with continuous operations, such as care and healthcare, are sequenced around clinical and resident routines rather than around the build programme.
What happens after the installation is commissioned?
You receive MCS certification, electrical certification, DNO approval documentation, O&M manuals and as-built drawings. From there, PV should be monitored and serviced - visual and structural inspection, electrical testing, performance checks against expected generation, and cleaning where site conditions justify it. Rossair carries that as a PPM contract, so the installer and the maintainer are the same company.
Can you install battery storage at the same time?
Yes, and it is normally cheaper to do both together - one design, one DNO application, one scaffold and one commissioning visit. Storage can also be retrofitted later once the array has produced a year of real generation data to size against. Both routes are covered on our solar battery storage page.

If we’re not the right fit, we’ll tell you who is

Book a commercial solar installation survey

Tell us the building, the roof and roughly what you spend on electricity, and we will come back with what is worth doing - including if the answer is not much.

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