You can safely clean solar panels yourself if you can reach them from the ground with a soft brush and plain water, and if you are only dealing with light dust. Anything that needs you on the roof, and anything involving lichen, bird mess or a system that has not been touched in years, is worth paying for. The dividing line is not really skill, it is whether you have to get on the roof.
Here is the honest version of the trade-off, including where DIY genuinely makes sense.
What you can safely do yourself
- Rinse from the ground with a hose and a soft-bristled brush on an extension pole, on a single-storey home with an accessible array.
- Use plain water. Cold or lukewarm, early morning or evening. Never on hot glass.
- Clear obvious debris like leaves and branches that have collected at the panel edges.
- Check your inverter readings regularly so you notice a drop early.
Done between professional visits, this genuinely helps, particularly for pollen and light dust.
What you should not do
- Never use a water blaster. High pressure forces water past the edge seals of the panel laminate. It is one of the fastest ways to void a panel warranty, and you will not find out until you make a claim and it is declined.
- Never walk on panels. Glass looks solid and is not. Foot pressure causes microcracks that are invisible from the ground and permanently reduce output.
- No detergents, solvents or abrasives. Household cleaners leave a residue that attracts dirt faster than before, and abrasives scratch the anti-reflective coating, which is the part doing the work.
- No scrapers or hard brushes on lichen. Scratched glass is permanent.
- Do not go on the roof without a harness and the training to use it. This is the one that actually injures people.
What a professional clean adds
Three things you cannot replicate from the ground.
Pure water. We use deionised water, which has had its mineral content stripped out. It dries without leaving spots or a film, so panels stay cleaner for longer than they would after a tap-water rinse, which deposits minerals as it dries.
The inspection. Cleaning is only half the visit. Ours includes a 7-point check covering cable and conduit condition, panel fractures, moisture ingress, rust and corrosion on frames and fixings, the structural integrity of mounting and tilt kits, bird and insect nesting, and inverter operation. Those are the problems that quietly cost you money, and none of them are visible from the ground.
Documentation. Before and after photos, inverter readings either side of the clean, and a written report. That record matters, because many panel and inverter warranties require documented annual maintenance and a claim can be declined without it.
What it costs either way
DIY costs you a brush, a pole and an hour or two, plus the risk. A professional clean for most New Zealand homes is $275 to $395 including GST, set by panel count and whether the house is single or double storey. Full detail on the pricing page.
Worth knowing: you can find people who will put a water blaster over your panels for about $10 a panel. That is cheaper, and it is the single most common way we see systems damaged. A cheap wash is not the same product as a maintenance visit, so compare what is actually included before comparing prices.
So which should you do?
DIY is reasonable if your array is single-storey and reachable from the ground, the panels are only lightly dusty, and you are happy rinsing with plain water and a soft brush between professional visits.
Pay someone if your house is two storeys, the roof is steep or fragile, there is lichen or moss, birds have been nesting, the system has not been cleaned in years, your output has dropped and you do not know why, or your warranty requires documented maintenance.
Most people land on a professional clean once a year, per AS/NZS 5033 and typical warranty terms, with a ground-level rinse in between if they feel like it.
Frequently asked questions
Can I use dish soap on solar panels?
Better not to. Detergent leaves a film that attracts dirt faster, so the panels look good for a fortnight and are dirtier than before within a couple of months. Plain water, or deionised water if you want them to stay clean.
Will cleaning my own panels void the warranty?
Cleaning them gently with water will not. Pressure washing, walking on them or using abrasives can, and so can failing to maintain them at all if your warranty specifies annual maintenance.
Is a hose enough?
For light dust, largely yes. For salt film, sap, lichen or bird mess, no. Those need contact cleaning and, in the case of lichen, a dedicated treatment.
What about those robotic cleaners?
They exist and they work on large commercial arrays. For a residential roof the equipment cost is far beyond what a few professional visits would cost you.
Get a price for your roof
We service Auckland, Waikato, Bay of Plenty, Rotorua, Taupō, Whakatāne, Northland, Taranaki, Hawke’s Bay, Gisborne, Coromandel and Wellington.
Get a free quote, or read about what a professional clean includes.