Extended Inverter Warranties

rustybucket43

Our PV system was recently commissioned and is working well.

We paid an extra £250 to extend the inverter warranty from 10 years to 15 years.

We have received an extended warranty certificate from the manufacturer (Growatt) saying that the warranty ends in June 2039. That's just over 14 years from installation.

Growatt seem to base their warranties on the date the product leaves their factory. The warranty procedure says:

"10 years starting from the date of installation and for no more than ten and a half years from the delivery date from Growatt".

In my case it seems as if the inverter I received spent much longer than 6 months getting from the factory to being installed.

I queried this with the installer and they showed me an invoice showing it had been purchased from a trade distributor in the UK in April 2025. It was installed in May 2025.

Is it reasonable that I lose some of my extended warranty due to circumstances beyond my control? The inverter must have spent months in storage in various warehouses and being shipped around before coming to me.

Where do I stand legally? Can I expect the warranty to start on the date of installation or commissioning?

It would be just my luck that the inverter fails in July 2039 after the warranty has expired !

Any thoughts?

Netexporter

I wouldn't buy an extended warranty in the first place. Assuming it is a 3.68kW inverter, for a G98 connection, a new inverter will probably not cost much more than the cost of the extra warranty.

rustybucket43

Netexporter said:

I wouldn't buy an extended warranty in the first place. Assuming it is a 3.68kW inverter, for a G98 connection, a new inverter will probably not cost much more than the cost of the extra warranty.

It was for a bigger (G99) inverter than that but the question wasn't about the merit of having an extended warranty or if it's good value.

Rather, I am interested in whether the date an inverter leaves the factory (in China) can reasonably be used as a starting point for a warranty.

Netexporter

IANAL but you have paid for a 5 year extension to a standard warranty, which you have got. If the terms of the base warranty fall foul of the Sale of Goods Act then you might have a case but whether it is worth perusing is your decision. 

born_again

Manufacture can set whatever warranty terms they want.

Just how much are you losing?

Screwdriva

rustybucket43 said:

Rather, I am interested in whether the date an inverter leaves the factory (in China) can reasonably be used as a starting point for a warranty.

It's a terrible way to word a warranty (typical Growatt for you). You can try challenging them in court but I suspect the magistrate will rule in their favour given that the warranty terms were available to you prior to purchase. 

I recommend leaving a factual review on Trustpilot to make sure others learn from your experience. 

Netexporter said:

I wouldn't buy an extended warranty in the first place. Assuming it is a 3.68kW inverter, for a G98 connection, a new inverter will probably not cost much more than the cost of the extra warranty.

This is not correct. While I can't speak for Growatt as I refuse to advocate for those types of brands, SolarEdge extended warranties cost ~15% the cost of new inverter but covers the inverter for 20 years (vs 12).

So far, I know of 4 inverters that have failed (of 150+ installs I have helped others with). All 4 units were replaced within 3 weeks of failure - no prorated compensation offers. No gimmicks. Their warranty starts from the date of installation. 

All installations I have helped with include an extended warranty as part of the quote (the installer must include this at zero premium to the end user)  as I am convinced this is beneficial over the life of the system. 

rustybucket43

Netexporter said:

IANAL but you have paid for a 5 year extension to a standard warranty, which you have got. If the terms of the base warranty fall foul of the Sale of Goods Act then you might have a case but whether it is worth perusing is your decision. 

It's true that it's a 5 year extension to a standard warranty. I totally get that.

rustybucket43

born_again said:

Manufacture can set whatever warranty terms they want.

Just how much are you losing?

I'm losing about 10 months. So, the warranty will be 14 years and 2 months rather than 15 years after installation.

I'm more interested in the principle. What if the inverter had left the factory in 2020 and spent 5 years languishing in a dark dusty warehouse until it made its way to me? That could happen if a distributor doesn't rotate his stock or products get misplaced in his warehouse.

It doesn't seem reasonable that a significant period of the warranty can be consumed by factors outside my control. That makes buying a complete lottery as we have no idea when it will have left the factory.

Netexporter

Caveat emptor. You could have read the terms of the standard warranty and chosen another brand if you didn't like the terms.

QrizB

Screwdriva said:

..  SolarEdge extended warranties cost ~15% the cost of new inverter but covers the inverter for 20 years (vs 12).
So far, I know of 4 inverters that have failed (of 150+ installs I have helped others with).

Those 150 installations have paid SolarEdge for 22.5 inverters (15% of 150) and SE have supplied 4 inverters in return (and those 4 were covered under the original 12-year warranty). That's a pretty good deal from SE's perspective.

A paid-for warranty, like all insurance, will on average cost more than the value you get back. It's only worth taking if it's for an eventuality you can't afford to pay for.

Waywardmike

After looking at the Growatt Trustpilot page posted above it looks like things are improving. Their Trustscore used to be appalling but now it's better than SMA or Victron energy and not too dissimilar to SolarEdge.

Looking at the reviews it appears the support is somewhat hit or miss, so whether your inverter dies at 1 year, 10 years or 14 years, I think the support you receive will be luck of the draw. Read the reviews for all the solar equipment companies, it appears that's an industry wide problem.