Solar panel problems and how to solve them

Solar panels are generally quite reliable. Many owners don't experience technical faults in over a decade of ownership.

The most common – and most serious – problem owners face is with the inverter. In some cases inverter problems mean you don't get any usable renewable electricity. 

It can also be a pricey problem to fix. But if you know about it, you can factor repair costs into your investment.

Here we run through some of the most common problems with solar panels. We spoke to Which? Trusted Trader Ceiba Renewables and looked at guidance from industry body Solar Energy UK and standards body MCS.

If you’re considering installing solar panels, check out our Solar panel installation guide.

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Solar panel inverter problems

Solar panels can have warranties of up to 20 or 25 years, but inverters aren't expected to last as long.

You should expect to replace your inverter at some point during the life of your solar panels. 

Find out how much you should expect to pay for a new inverter and other tips to make the most of your solar panels.

If your inverter isn't working, you won't be able to use the electricity generated by your solar panels, so it's important to get it fixed quickly.

If you have recently had a power cut, check that the solar PV breaker in your consumer unit is in the on or up position. If it trips to the off position, call an engineer; if it stays on, check the inverter for error messages. 

Refer to the manual or search online to find out what the error message means.

Check if your inverter is still within its warranty. If so, contact the company about the fault. If not, contact your solar panel installer for professional advice on replacing it. 

Find a reputable solar panel installer using Which? Trusted Traders. You can also use our Trusted Traders search tool below to find local solar panel experts in your area.

Solar panel electrical problems

Electrical problems could be caused by:

• faulty materials
• poor workmanship
• other electrical works at your home that have an impact
• loose connections
• a variable voltage coming into your home from the grid
• wear and tear to the DC electrical cables that join the panels together (caused by water getting into them or chafing on roof tiles).

Check your inverter in the first instance. Its error message (or code) could tell you the cause.

Call a solar panel mainteance professional, rather than attempting to fix an electrical problem yourself.

Birds nesting under your solar panels

Birds – or even squirrels – making their home under your solar panels is a pain, especially if they scratch them, damage the wiring or soil them.

You can buy plastic strips and attach them to the panels to help stop animals being able to squeeze underneath. Other solutions including fitting bird mesh or netting around them.

Or if you’re thinking of installing solar panels, consider roof-integrated panels. These can be complex to retrofit but are built into the roof, leaving no gaps for birds or rodents to get into.

Dirty solar panels

Dirt might be caused by bird droppings, traffic pollution if you live in an urban area, or a build-up of salt if you live near the coast. 

A heavy rain storm should usually be enough to wash off most dirt. Unless the build-up is very thick or a significant amount accumulates on one panel (perhaps a pigeon sits on your TV aerial and its droppings fall onto one panel) it's unlikely to cause a problem beyond a slight drop in generation.

Solar panels producing less electricity 

A drop in electricity generation is most likely cause by weather conditions, dirt building up or a change in the environment. 

Misty mornings will impact the generation of east-facing panels, in particular. Thick cloud will mean that your panels produce less electricity than on bright sunny days. 

Some years are sunnier than others and this has an impact on how much electricity your panels will generate.

Secondary causes are dirt building up on your panels (see above for how to solve this), trees growing above your panels and shading them, or a problem with a connection or component behind a panel.

Less-than-perfect weather conditions are a fact of solar pv life and there’s nothing you can do about it. 

If you suspect there might be something else behind a drop in electrical production, look at your panels and their surroundings closely to check for shade that might not have been present when your panels were installed.

Solar panels not working

If your panels aren't producing any electricity when you'd expect them to, it's most likely a fault with the inverter or problem with the wiring. 

Occasionally the generation meter might fail. If this happens, you’d see no recorded generation, even though the system is working.

The longer you go without your panels producing electricity, the less renewable power you'll use and the more you'll buy from the grid. Plus you'll lose out on any feed-in tariff or Smart Export Guarantee payments.

First check the solar pv breaker in your consumer unit. It should be in the on/up position. If it’s in the off/down position (which can happen after a power cut) try to flick the switch back on. If it trips back to the off position, leave it off and call an engineer. 

Also check your inverter for any fault codes or error messages.

Broken solar PV generation meter

Check the real-time and cumulative generation on your inverter (most have these options) to make sure that the solar panels are still generating electricity. 

If the system is generating at the inverter this implies a failed generation meter.

If the fault is only with the generation meter, the panels should still be generating and feeding electricity to your property. 

But if you're claiming the feed-in tariff and don't have a smart meter, you won't be able to take meter readings (required to calculate your payments).

Contact your solar panel installer or a solar panel maintenance professional.

Find a reputable solar panel installer using Which? Trusted Traders.

Cracked or broken solar panels

This rarely happens after installation. If you suspect that a solar panel has cracked it would most likely have been caused by impact. 

Solar panels from MCS-registered brands are made with tempered glass so will shatter rather than crack, like a car windscreen.

Cracking shouldn't much affect the output of the panel. See if you can get a replacement panel under warranty. 

If not, you have time to budget for a replacement panel (ideally matching in size, make and model.

You should get a professional to replace the panel.

Isolator problems with solar panels

You should have two isolators: one at the inverter and one close to the consumer unit. A problem could be caused by loose internal connections or moisture. 

Your inverter will show an error if this is the case, and the code it displays should help identify if the fault is on the AC or DC side.

If you suspect an isolator problem, follow the shut-down procedure that should have been left with you by your installer. If you don’t have one, turn off the PV breaker switch at the consumer unit.

You should get this issue investigated urgently by a qualified electrician. They will probably use the fault codes on your inverter to do this.

If you're still choosing your solar panels, use our buying advice for solar PV guide to find the right system for your home.