The rollout of 50m smart meters to UK properties has been delayed by more than a year, the government has revealed.
The Department of Energy and Climate Change (DECC) will now start the £11.7bn scheme in the autumn of 2015 rather than the originally-proposed summer of 2014.
Energy secretary Ed Davey said in a written statement to parliament on Friday: "The consistent message was that more time was needed if the mass roll-out was to get off to the best possible start and ensure a quality experience for consumers."
The announcement comes after the government asked the energy industry how long it would take to design, build and test the communications systems that would be used to send meter readings to energy suppliers from people's homes.
The smart meter technology is designed to show people exactly how much gas and electricity they are using in their homes each day, which could enourage some to be more energy efficient.
Davey said: "The government has decided to move the completion date for the mass roll-out from end 2019 to end 2020 — although I expect the vast majority of smart meters to be in place against the original 2019 deadline."
He said that the national rollout of smart meters would be an enormous logistical and technical challenge.