A third of smart meter owners have had problems with their devices, ranging from them "going dumb" to failing to function entirely, a survey suggests.
The figures come as one in five households (20%) say they have been offered first-generation SMETS1 meters since March, despite the Government and Ofgem saying they should be installing second-generation SMETS2 devices after this date.
Some 31% of households have had problems such as displays not working (39%), devices "going dumb" after switching (32%), or meters ceasing to function entirely (13%), the poll for uSwitch indicates.
A third of households (33%) with SMETS2 meters - which are supposed to remain in smart mode regardless of switching and which were not expected to experience technical problems - have also encountered issues since they were installed, the poll suggests.
More than half of households (53%) believe their supplier did not fully explain the benefits of their meter prior to installation.
However, more home-owners (29%) now believe that owning a smart meter has helped decrease their energy bills, up from 16% in 2018.
This awareness has led to 38% of meter users saying they now turn off lights when they are not in the room compared with 33% last year, and 22% now washing clothes at a lower temperature, up from 18% last year.
Smart meter owners say changing their habits has helped them save around £108 a year on average.
More than a fifth of homes (22%) still report feeling pressured by their supplier into taking a smart meter, though this is down from 30% last year.
Some 5% said their supplier tried to install a meter without their permission, but this is also down from 11% last year.
Rik Smith, energy expert at uSwitch.com, said: "While it's great to see smart meters improving energy habits and helping consumers to save on their bills, there are still far too many issues with the rollout which are damaging consumer confidence in the whole scheme.
"There is a real opportunity to build more confidence in smart meters now, if households are given the right information to make the most of their new device and they're only offered a second-generation meter which shouldn't go dumb if someone switches supplier."
Robert Cheesewright, of Smart Energy GB, said: "Thousands of second-generation smart meters are being rolled out every day - in the coming days the two millionth second-generation meter will have been installed.
"As more and more smart meters are installed, we are all playing a part to upgrade and decarbonise our outdated energy system."
Energy UK chief executive Lawrence Slade said: "Customers with smart meters continue to report high levels of satisfaction and it's pleasing to see from this survey an increasing number of people are reporting their smart meter is helping them reduce their bills and make them more aware of their energy usage.
"Additionally, smart meters are essential if we are to deliver the flexible energy system that will help us to achieve our net-zero target by 2050."
A Department for Business, Energy and Industrial Strategy spokesman said: "The replacement of traditional gas and electricity meters with smart meters is a vital national energy infrastructure upgrade that will make our energy system cheaper and more efficient for consumers.
"Anyone experiencing problems with their in-home display should contact their supplier, which is obliged to replace it free of charge if it's not working properly."
Opinium surveyed 2,011 adults who have a smart meter, online, between July 26 and August 1.