It also means that many customers are, as before, have credits on their accounts of hundreds of pounds.
Errors with meters also mean that wrong information is being sent and acted upon by suppliers.
Angela Forman, who lives in East Sussex, agreed to have a smart meter installed after being told it would remove the need to send monthly meter readings. She had been on an Economy 7 tariff, which takes separate readings in day and night, when energy demand and cost is lower.
However when she received her first bill under the smart system it was for £114, much higher than her usual £94. Her meter had a fault and was sending her energy company an estimated reading, actively costing her money.
And horror stories have swamped social media of customers being billed tens of thousands of pounds incorrectly.
Mark Umpleby tweeted SSE with a photo that said he had used £33,183 of gas in one day - 2,765,175 per cent over budget. Another customer, Usman Hussain, tweeted a picture of his meter saying he would be charged nearly £9,600 for his day's electricity and gas.
3) Smart meters won't work if you have a poor signal in your area
The successful operation of smart meters can also be a postcode lottery. Live in an area with poor mobile signal? There's a chance your smart meter won't work.
This was the issue for Mrs Forman. The mobile reception was not good enough, which forced her smart meter to revert to "dumb mode" and send estimated readings.
Another reader, Suzanne Harvey, had a smart meter installed in 2014 and was told by the engineer who fitted it that the poor reception might create difficulties. This proved to be the case and she failed to receive a bill for almost a year.
Smart Energy GB expects the rollout of the national network to make the meters independent of mobile coverage - effectively fixing this problem.
4) The display units linked to smart meters are crude and difficult to understand
Many have complained that the "smart interface" of their meter - the device which sits inside the house and displays data about usage and cost - is difficult to understand.
The hope is that mobile apps will be developed which are more user-friendly.
Ovo, one of the newer providers and an advocate of smart meters, has an app which shows usage and readings updated by week. It also shows any current balance as well as usage and cost over recent months.
5) There's little evidence so far that smart meters will save energy - or money
The policy on smart meters was first championed by former Labour leader Ed Miliband - and later by the Tories - as a way of bringing down Britain's energy use. They had been popular in Europe for this reason.
However, some argue that there is no real evidence to back up the claim that the smart meter could revolutionise our energy habits.
In fact, devices which are designed to reduce usage, including energy-saving LED lightbulbs and dimmer switches, can actually "change the shape" of electrical currents and distort readings. A Dutch study found this resulted in readings up to six times higher than they should have been.
The policy on smart meters was first championed by former Labour leader Ed Miliband.
If consumers are using a smart meter to track and reduce their daily usage, their efforts could be stumped by such glitches.
Even where meters are working as planned, savings are small. Little data exists as yet but one provider, British Gas, has said that its customers using smart meters save on average £30 a year.
6) Smart meters 'pose security and other risks'
Before the smart meter rollout many experts highlighted security fears about the devices, claiming they could be hacked.
Security experts warn that the smart meters can be infected with a virus that can spread between different devices, and cutting some individual energy supplies off. Others warn that they could even be hacked and used for terrorism.
The Financial Times reported a year ago that intelligence service GCHQ intervened to protect the network, after fears that a hacker could gain access to every smart meter and "start blowing things up". The authorities consistently reassured the public that the devices were secure and safe.
An investigation by BBC Watchdog, which aired in late July, also raised questions about the links between smart meters and fires. It was not clear whether the meters themselves, or their installation, was at fault.