We recommend one to two cleans a year, depending on the area and what your panel warranty asks for. Rain helps on a pitched roof, but it does not shift bird droppings, farm dust, sap, traffic film or salt. We clean with purified water and soft brushes, never pressure washers.
We recommend one to two cleans a year, for homes and businesses alike. Which end of that range you need depends on the area your panels are in and what your panel warranty says. Rain helps: LONGi, one of the largest panel makers in the world, says in its installation manual that panels should be tilted at no less than 10 degrees so rain can wash dust off, and that how often they need cleaning depends on how fast dirt builds up. So a steeper roof in clean air sheds more on its own than a flat roof next to a farm or a busy road.
Rain does not shift everything. Bird droppings, sap, farm dust, traffic film and salt stay on the glass until someone cleans them off.
Check your panel warranty too. LONGi, for example, makes the owner responsible for regular inspection and maintenance during the warranty period, so a dated record of each clean is worth keeping. We go through the evidence in do solar panels need cleaning in the UK?
Industry guidance does not set one cleaning schedule for every roof. Solar Energy UK's Rooftop O&M Guidelines, the current edition published in December 2025, cover cleaning for homes and businesses and treat every installation as different. These are the conditions that push a roof towards two cleans a year rather than one.
Droppings do not rinse off the way dust does, and pigeons nesting underneath produce a constant supply. This is the most common genuine reason a domestic array needs cleaning, and it usually needs bird proofing as well, or you will be paying us again next year.
The flatter the panel, the slower water runs off and the more residue it leaves behind. Flat-roofed commercial arrays are the clearest case of all, and they are the reason the commercial side of this service exists.
Sap, pollen, leaf litter, and the birds the tree brings with it. Shading is a separate problem and we will look at that too while we are there.
Ploughing, harvest, grain drying, livestock buildings. Farms are a genuine high-soiling environment, which is why it appears as a section on our farms page rather than as an upsell.
Quarries, works, and busy roads deposit a film that rain alone does not shift.
Salt builds up and does not rinse clean.
If your monitoring shows output falling and there is no fault, soiling is one of the suspects worth ruling out. It is not the first suspect. See why generation drops.
If none of those describes your site, one clean a year is usually enough. In between, look at the panels from the ground now and then: MCS's own maintenance schedule asks someone who owns their home to do that once a year.
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Light, even dulling across the whole array is what a routine clean takes off. Streaks, white deposits, dark patches or an obviously dirtier band along the bottom edge of the panels mean a clean is due sooner.
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Can you see nesting material, feathers or droppings on the roof below? That is a bird problem, not a cleaning problem, and cleaning alone will not fix it.
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Compare this month with the same month last year. A gradual decline that tracks a dry spell points at soiling. A sharp drop points at a fault.
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Panels from the ground, and the underside of the array if you can see it. We will tell you what they need and what it would cost.
We price commercial and farm cleaning by the day, typically £800 to £1,500 a day depending on the size of the system and how dirty it is. Smaller domestic jobs are priced individually.
What actually moves the price on a quote from us:
| Factor | Effect |
|---|---|
| How the array is reached | The single biggest factor. Ground-level water-fed pole is quick. Scaffolding or a platform is not |
| Panel count and layout | More panels, more time. A split array takes longer than one block |
| What is on there | A light film is a wash. Bird fouling, lichen or sap is a different job and we will say so before we start |
| Roof height and pitch | Two-storey and steeply pitched roofs need different access equipment |
| Whether proofing is needed too | Cheaper done in one visit than two |
We quote from photographs wherever we can, so you are not waiting on a site visit to find out what it costs.
You will see companies advertising that a clean boosts output by 25%, 42%, or some other confident number. Ask where it comes from.
We looked for a credible UK study establishing a universal generation uplift from cleaning a normal domestic array, and we could not find one. Solar Energy UK confirms soiling reduces output, but describes the effect as site-specific, which is a different claim entirely. A meaningful figure would need before-and-after readings on your roof, adjusted for the weather either side. A number in an advert is not that.
The Advertising Standards Authority has been upholding complaints about this kind of claim across the solar industry, including a ruling in March 2026 against an "up to 94%" bill-saving headline. The pattern in those rulings is consistent: an "up to" label does not rescue a figure that most customers will never see.
So we do not publish one. What we will do is take a monitoring reading before and after, on your system, and show you what actually changed.
Purified water and a soft brush on a water-fed pole, from the ground wherever the roof allows it.
No pressure washers. They can force water past the panel seals and damage cells, and using one is a well-known route to voiding a manufacturer's warranty.
No detergents or abrasive pads. Same reason. Purified water dries without leaving the deposits tap water leaves behind, which is the whole point of using it.
No walking on your roof unless there is genuinely no other way to reach the array, and then only with the right access equipment and a method statement.
We follow your panel manufacturer's instructions, which sometimes means isolating the system first and sometimes does not. We check rather than assume.
The cleaning itself is delivered with our partner Pristine Panels, who do nothing else. We hold the electrical accreditations and sign off every job. Two specialists working as one is a better arrangement than one company claiming to be expert at everything.
Commercial and farm roofs get dirtier than most.
Flat and shallow-pitched commercial roofs shed dirt poorly. Farm buildings sit in constant dust. Industrial sites deposit a film that rain does not lift.
What we bring to a commercial site: site-specific risk assessments and method statements before anyone arrives, the right access equipment for the roof, public and employer's liability cover of £10 million, work scheduled around your operations, and a dated report of what we found and what we did. If the array is worth inspecting at the same time, we will say so, because we are on the roof anyway and it is cheaper than a second visit. That is our maintenance service.
How often, and where. We recommend cleaning commercial and farm arrays once or twice a year, depending on the site and what the panel warranty asks for, to keep up with the warranty and the efficiency of the array. We clean warehouse, factory and farm roofs anywhere in the UK from our base in Warrington.
And a note on size. Several of the larger contractors will not quote below a couple of hundred panels. We will. The pub with forty, the care home with a hundred and twenty, the farm with one barn roof: that is ordinary work for us, not an exception.
Yes. We recommend one to two cleans a year, depending on the area your panels are in and what the panel warranty asks for. Rain helps on a pitched roof, and LONGi says panels should be tilted at least 10 degrees so it can, but rain doesn't shift bird droppings, farm or industrial dust, sap or salt, and it barely runs off a shallow roof.
We recommend one to two cleans a year, depending on the area and what your panel warranty asks for. A steeper roof in clean air sits at the lower end; birds, trees, farm dust, traffic film or a shallow pitch push it towards twice a year. In between, look at the panels from the ground now and then, as MCS's maintenance schedule asks a homeowner to do once a year.
Twice is more likely if any of these apply: visible bird fouling, overhanging trees dropping sap or leaves, a busy road nearby, agricultural dust, coastal salt, a shallow or flat roof where rain runs off too slowly, or generation that has dropped without another explanation. Check your panel warranty as well, because it may say what is needed.
It can, but by how much depends entirely on how dirty the panels were. On a lightly soiled pitched roof the change is usually small; under heavy bird fouling or farm dust it can be large. We have not found a credible UK study that supports one figure for every roof, so we don't quote one. Instead we take a monitoring reading before and after, so you can see what changed on your own system.
Doing nothing lets dirt build up that rain won't shift, and some panel makers, LONGi for one, make the owner responsible for looking after the panels during the warranty. Paying someone makes most sense when the panels can't be reached safely from the ground. If they can, you can clean them yourself the way the maker describes.
If you can reach them safely from the ground, you can. Book us when they can only be reached from a ladder, scaffold or the roof, when droppings are baked on, or when birds are nesting underneath. We price home cleans from photographs, so you know the cost before anyone visits. How to clean your own panels safely.
No. We clean the way panel makers ask: purified water and soft brushes only, no detergent and no pressure washer, and we follow your panel maker's instructions on whether to isolate the system first. If your warranty asks for cleaning at set intervals, tell us when you book and we will fit the visit around it. What panel makers allow if you clean them yourself.
We price commercial and farm cleaning by the day, typically £800 to £1,500 a day depending on the size of the system and how dirty it is. Smaller home jobs are priced individually from photographs, so you know the cost before anyone visits. Access is the biggest factor: ground-level pole work is quick, scaffolding or a platform is not.
Once or twice a year, depending on the site and what the panel warranty asks for, to keep up with the warranty and the efficiency of the array. Flat and shallow-pitched commercial roofs shed dirt poorly, and farms produce dust and bird fouling all year, so these sites usually sit at the top of that range.
Yes. We are based in Warrington and clean warehouse, factory and farm roofs across the North West and the rest of the UK. We send risk assessments and method statements before the visit, carry £10 million liability cover, work around your deliveries and shifts, and we will quote for small sites that bigger contractors turn down.
We follow the manufacturer's guidance for your specific system, which sometimes means isolating it and sometimes does not. Our teams work to method statements that cover isolation, water use and safe roof access.
One of the panels from the ground, one of the underside of the array if you can see it. We will tell you what they need, roughly what it would cost, and whether anything else is going on up there.
The form takes text only, so send the photos on WhatsApp. We reply to every enquiry within two working days, usually the same day. We clean solar panels for homes, businesses and farms across the UK from our base in Warrington, whoever installed them.
