Solar panels on a commercial roof
A rooftop array generates electricity you use on site, which is worth far more than electricity you export. That single fact decides most commercial solar cases.
Panels are fixed to the roof of your building and wired into your incoming supply. Whatever the array produces is used by the building first. Anything left over goes out to the grid.
The value is lopsided. Electricity you use yourself displaces the grid rate you pay. Electricity you export earns the export rate, which is a fraction of it. A warehouse running plant through the day therefore does far better than a building that is empty on weekdays.
It suits single storey buildings with a wide roof and daytime load. Distribution units, manufacturing, retail parks, cold stores, leisure centres and offices with air conditioning are all normal cases.
It suits you less if you lease the roof and cannot get the freeholder's authority, if the roof is at the end of its life, or if the building sits empty during daylight hours.
- -Usable roof area, and how much of it is clear of plant, rooflights and shading.
- -Roof condition and remaining life. An array is a twenty five year asset on a roof that may not have twenty five years left.
- -Your export headroom at the connection. A site can have plenty of roof and no permission to export.
- -How much of your consumption falls in daylight hours, which is why half hourly data changes the answer more than anything else on this list.
- -Who owns the roof, and whether a lease permits the work.
The figures Meridians models with. Your building replaces them with its own data as soon as we have it.
- Installed cost
- from 450 to 620 per kWp
- Derived from real commercial installer proposals rather than a published average.
- Roof area needed
- 5.5 to 8 square metres per kWp
- UK commercial rooftop market data, 2026.
- Annual yield
- 750 to 1,100 kWh per kWp per year, depending on region
- UK regional solar yield data, 2026. Southern England sits at the top of that range and Scotland at the bottom.
- Share used on site
- 50 to 85 per cent
- Typical commercial rooftop range. Your own half hourly data replaces this as soon as we have it.
Grid electricity is taken at 20 to 27 pence per kWh, from 2026 UK commercial rates.
Cost leads with the low end. Payback leads with the longer one.
The card a client sees, rendered by the application itself.
Modelled from the consumption figure you gave us, so an installer survey may land elsewhere in these ranges.
- -The array is sized to the roof rather than to the load, so a large share is exported at a low rate and the payback lengthens.
- -Export headroom is discovered late, after design work has been paid for.
- -The roof needs replacing within a few years and the panels have to come off and go back on.
- -A single annual consumption figure is used instead of half hourly data, so the daytime share is a guess.
On site generation reduces the modelled energy use of a building, so it can move an EPC rating.
See it on your buildings
Add your sites and their energy data, and you get a modelled range for this measure at each one rather than a market average.