Smart appliances that can be controlled remotely and will let you know if there is a fault or other problem may not be worth paying extra for unless manufacturers commit to keeping software updated, Which? has warned.

The consumer group said that smart fridges, dishwashers and tumble dryers cost hundreds of pounds more than their conventional counterparts, but in some cases could be rendered obsolete after as little as two years.

It surveyed major manufacturers about their plans to issue the software updates needed to keep the products working. It found the majority of manufacturers said they would offer updates for “the life of the product”, but did not specify how long that was.

Samsung told the organisation this was a minimum of two years, Which? said, while Beko said a maximum of 10 years.

[This update was inserted on 16 June 2020. After publication, Samsung contacted the Guardian to say that for “critical security vulnerabilities” software would be updated for “the reasonable life of the product”. A Which? spokesperson said the organisation had earlier pressed Samsung to clarify how long this would be, but without success.]

Other major firms did not give a specific time period when asked. BSH (which makes Bosch, Neff and Siemens appliances) said it would provide updates for the lifetime of the product; in this case, too, Which? was unable to establish what “lifetime” meant in practice.

Only Miele was definitive, Which? said, stating it would provide 10 years of updates.

Which? said the cost of smart items was much higher than standard products, with consumers paying an average of £855 more for a smart fridge-freezer, £259 more for a smart dishwasher and £190 more for a smart tumble dryer. 

Typically dishwashers and washing machines last for 10 years before they are replaced due to faults or poor performance, while fridge-freezers and tumble dryers last for 11 years, it said. 

Without regular updates, smart items could lose functionality and security could be compromised, leaving the owner’s network open to hackers. Many of the products will still work without their smart features, but not all.

Which? said a new sales of goods directive from the EU would force manufacturers to state upfront how long products would be updated for, but it was not clear when this would be introduced in the UK, and it did not specify how long the period should be.

Natalie Hitchins, the head of home products and services at Which?, said: “Until manufacturers are clear and upfront about how long they will support these products for, consumers could be better off avoiding smart appliances that might turn ‘dumb’ after only a few years and stick to more reliable and significantly cheaper non-smart alternatives.”

• This article was updated on 16 June 2020 to insert comments by Samsung and Which? about the duration of software updates for Samsung appliances, and for BSH appliances.