The firm analysed products including washing machines, dishwashers, televisions, smartphones, printers and smartwatches and found that hardly any brands came close to matching expected lifespans with their smart update policies.
The failure to update their cyber defences also leaves some of the products open to hacking, Which? warned.
Many brands were found to not give any guarantees, meaning consumers were unaware how long their appliance would be supported upon purchase.
Appliances with smart home integration typically cost more than their non-smart counterparts – for example, a smart dishwasher costs on average nearly £300 more upfront, at £746 versus £455
119 product brands were surveyed about their update support policies and it was found that in most cases, the support period was significantly shorter than the time that the product typically lasts.
LG dishwashers, smart TVs and washing machines for example, are all only guaranteed support for two...