Solar inverter replacement in the UK typically costs between £500 and £1,500 installed for a standard string inverter — and if your system was put in during the Feed-in Tariff years (2010–2016), there is a good chance you are due one now, or will be soon. The inverter is the one component your panels will outlive, and when it goes, your whole system stops generating until it is fixed.
This guide covers exactly what you need to know: how long inverters last, how to tell when yours is failing, what replacement realistically costs in 2026, and whether this is the right moment to upgrade to a battery-ready hybrid inverter. No fluff, no scare tactics — just the honest picture.
How Long Does a Solar Inverter Last in the UK?
Most standard string inverters last around 10–15 years — significantly less than the 25-plus years your panels are designed to run. The Energy Saving Trust explicitly advises homeowners to budget for at least one inverter replacement over the lifetime of a solar PV system.
The mismatch matters. Your panels carry 25-year performance warranties. Your inverter probably came with a 5–10 year manufacturer warranty. Once that warranty expires and the unit hits its early teens, you are into borrowed time.
Why do they fail sooner? The inverter is an active electronic device working continuously — converting DC electricity from your panels into usable AC, every day, through heat, cold and damp. Capacitors dry out, cooling fans wear down, and circuit boards degrade from thermal stress. It is simply a harder life than the panels have up on the roof.
One important variable: where your inverter is installed. Units mounted outdoors or in hot loft spaces degrade faster than those in a cool, ventilated garage or utility room. And if your inverter is from a brand that has since left the market — some early models from the Feed-in Tariff era no longer receive firmware updates or manufacturer support — that can shorten effective life further and make fault diagnosis harder.
My Solar Panels Have Stopped Generating — Is It the Inverter?
Quite possibly, yes — a failed inverter is one of the most common reasons a solar PV system stops producing electricity. But before assuming the worst, run through these checks first.
- Check the inverter display or LED. A red or amber light, an error code, or a blank screen on a sunny day is a strong indicator something is wrong with the inverter itself.
- Check your generation meter or monitoring app. If output has dropped to zero (or near zero) on a clear day, the inverter is the first suspect.
- Check your consumer unit. A tripped breaker or blown fuse related to the solar circuit can cut generation without the inverter itself failing — and is much cheaper to fix.
- Check for obvious damage. Scorch marks, a burning smell, or water ingress around the inverter casing all point to a unit that needs replacing rather than resetting.
If your system is generating some electricity but noticeably less than expected for the time of year, partial inverter failure or degradation is possible. An MCS-certified installer can carry out a proper diagnostic — always worth doing before committing to a full replacement, as occasionally the issue is elsewhere in the system (a faulty isolator switch or a loose DC connection, for example).
Not sure what normal output looks like for your system? Our guide on why your electricity bill might still be high with solar panels covers how to sense-check your generation figures.
How Much Does Solar Inverter Replacement Cost in the UK?
For a typical domestic solar PV system, solar inverter replacement in the UK costs around £500–£1,500 installed for a standard like-for-like string inverter. The Energy Saving Trust gives £800 as a typical figure for inverter replacement.
Here is a breakdown of what to budget by inverter type in 2026:
- Like-for-like string inverter (3–4kWp system): roughly £700–£1,100 including labour — a single engineer visit of around 2–4 hours.
- Like-for-like string inverter (larger 5–6kWp system): typically £900–£1,500 installed.
- Hybrid inverter upgrade (battery-ready, 3–4kWp): roughly £1,400–£2,200 installed — more upfront, but avoids a second replacement when you add a battery later.
- Hybrid inverter upgrade (5–6kWp): typically £1,700–£2,600 installed.
The final number depends on your system's size, the brand you choose, how accessible the installation point is, whether any rewiring is needed, and whether you opt for like-for-like or an upgrade. These are budgeting ranges — not fixed quotes. Get at least two or three prices before committing.
A note on VAT: the 0% VAT rate that applies to new solar installations is confirmed until 31 March 2027 under HMRC's VAT Notice 708/6. Whether a standalone inverter replacement qualifies for 0% or the reduced 5% rate depends on how the work is characterised — ask your installer to confirm the VAT treatment in writing before you sign anything. If you are adding a battery at the same time as the inverter replacement, the combined job is more likely to qualify for the zero rate. See our guide on 0% VAT on solar panels and the March 2027 deadline for more detail.
Should You Just Replace Like-for-Like, or Upgrade to a Hybrid Inverter?
This is the most important decision you will face at replacement time, and it is worth slowing down to think it through properly.
A like-for-like string inverter is the cheaper option right now. It gets your system running again at the lowest immediate outlay. If you have absolutely no interest in battery storage and your system is otherwise working well, a straightforward swap makes sense.
A hybrid inverter costs more upfront — typically an extra £400–£700 over a like-for-like replacement — but it manages both solar generation and battery charging. If you add a battery in the next few years using an old-style string inverter, you will face the cost of another inverter replacement at that point. Doing both in one job also saves on labour.
The maths shifts depending on whether battery storage is on your radar. If it is, paying the upgrade cost now is almost always cheaper than two separate jobs later. If it is not, keep it simple. There is no right answer — it depends entirely on your circumstances.
Our guide to whether solar battery storage is worth it is a useful read before you decide.
What to Do Next: Getting a Fair Price
Inverter replacement is a job that requires a qualified electrician — it falls under Part P of the Building Regulations. Using an MCS-certified installer is strongly advisable: they understand the full system, not just the box on the wall, and they are accountable to a regulated scheme. You can check any installer's MCS status at mcscertified.com.
Always get at least two or three quotes. Prices can vary significantly between installers, and the cheapest quote is not always the best — check what brand and model of inverter is being proposed, what warranty comes with it, and whether commissioning and grid notification (required under G98/G99 rules) is included in the price.
A few things worth asking any installer before you agree to the work:
- Is the proposed inverter compatible with my existing panels and any monitoring system I have?
- What warranty does the new inverter carry, and who do I contact if it develops a fault?
- Will you handle the G98/G99 notification to my Distribution Network Operator?
- What VAT rate will appear on the invoice, and why?
- If I want to add a battery in future, would this inverter support it?
For a broader look at what to watch out for when getting any solar-related work quoted, our guide on solar quote red flags is worth a read before you start ringing round.
Is Replacement Worth It, or Should You Walk Away?
Replacing an inverter on a well-functioning older system is almost always worth it — provided the panels themselves are still in good shape. Your panels are likely generating close to their original output (panel degradation is typically slow — around 0.5% per year) and still have years of productive life ahead. Spending £700–£1,500 to restore a system that could run for another decade or more is usually straightforward to justify.
When might it not be worth it? If the panels themselves are significantly damaged or degraded, if the roof they sit on needs serious repair work, or if the system is tiny (1–2kWp) and a full upgrade would serve you better. In those cases, it may make more sense to get quotes for a complete new system rather than patch the old one. That is a conversation worth having with your installer — an honest one will tell you if replacement does not stack up.
Facing an inverter replacement is also a good moment to review your energy tariff. Some export tariffs pay significantly better than others for the electricity you send back to the grid. Our guide to the best Smart Export Guarantee rates in 2026 is worth checking once your system is back up and running.
If you are unsure what is wrong with your system, or you want to compare replacement quotes from vetted, MCS-certified installers in your area, get free quotes through FairSolar — it takes a couple of minutes and there is no obligation.
Frequently asked questions
How long does a solar inverter last in the UK?
Most standard string inverters last around 10–15 years — the Energy Saving Trust advises budgeting for at least one replacement over the lifetime of a solar PV system. Your panels are designed to last 25 years or more, so you should expect to replace the inverter at least once before the panels are done.
How much does solar inverter replacement cost in the UK?
A like-for-like string inverter replacement for a typical 3–4kWp domestic system costs roughly £700–£1,100 installed in 2026. The Energy Saving Trust gives £800 as a typical figure. Upgrading to a battery-ready hybrid inverter costs more — typically £1,400–£2,200 for the same system size — but avoids a second replacement when you add a battery later.
My solar panels have stopped generating — is it definitely the inverter?
It is a strong possibility, but not certain. Check for error codes or warning lights on the inverter, and check your consumer unit for any tripped breakers related to the solar circuit first — that can be a quick, cheap fix. If neither resolves it, get an MCS-certified installer to carry out a diagnostic before committing to a full inverter replacement.
Do I pay 0% VAT on a replacement inverter?
It is not straightforward. The 0% VAT rate confirmed until 31 March 2027 applies to new installations of qualifying energy-saving materials. A standalone inverter swap is generally treated differently to a new installation, and may attract a reduced 5% rate rather than 0%. If you are replacing the inverter as part of a larger job — such as adding a battery at the same time — the position may be more favourable. Always ask your installer to confirm the VAT rate in writing before agreeing to any quote.
Can I use a different brand of inverter when I replace, or does it have to be the same make?
You can usually switch to a different brand — inverter replacement is a normal opportunity to upgrade to a better or more suitable model. The key requirements are that the new inverter is compatible with your existing panels and system voltage, that the installer handles the required G98/G99 notification to your Distribution Network Operator, and that all electrical work complies with Part P regulations. Your installer should advise on compatibility before any work begins.