By Judith Burns
Science and environment reporter, BBC News
There are a number of electricity monitors available in the UK
The government should require power companies to provide clear visual displays when they install smart meters in homes, says a report.
All houses are set to have smart meters by 2020, as part of efforts to cut household emissions of CO2.
But the report, from the Energy Saving Trust, says smart meters will be less effective without monitors.
Real-time graphics will allow people to see how much power they use and help them cut their consumption, it says.
The government announced the plan to install smart meters to monitor electricity and gas consumption in 26 million homes earlier this year.
As well as bringing benefits in terms of costs and emissions, the new meters will also mean an end to estimated bills and having to wait at home for readings.
However, the Energy Saving Trust says the government's plans do not require energy companies to provide separate energy monitors when they install the new meters.
It fears that without visual displays householders will find it harder to benefit from the smart meters and save power.
Focus group research presented in the report, The Smart Way to Display, shows a consumer preference for simplicity in visual displays of energy use.
Most people preferred a graphic indicator of their real-time rate of energy consumption, expressed in terms of expenditure per day.
A gauge of cumulative spend was also a popular idea. Consumers thought that these features would help them track consumption and pinpoint areas of high usage.
The focus group members also felt that the ability to access historical data on consumption and compare it with current levels was essential.
The trust's energy efficiency strategy manager, Ben Castle, told BBC News that only stand alone in-house display monitors could offer the immediate, direct and real time feedback on consumption that consumers need.
He said: "With a display, you have it in your house. It moves and it can catch your eye and it is very little hassle for you to check how you are doing. It gives a much greater certainty that people will receive this feedback.
"Other alternatives, such as online services and mobile phone technology, don't give that immediate feedback that people need to inform their behavioural choices.
"I think having good, well designed displays accompanying smart meters is key to the objective of saving energy, saving carbon, saving money for householders."
The display monitors would be either attached by a wire to the smart meter or they could work on a radio connection.
This would enable householders to put them in the most convenient place and to move them round the house in order to monitor electricity consumption.
The report says a minimum specification for energy displays is required to ensure that they give consumers the information they most need.
Old-style meters could be phased out by 2020
However it says that only one of the devices available in the UK meets these requirements.
The report focuses on electricity use, but says that the same design features should apply to gas or dual-fuel display monitors.
Responding to the report, a spokesperson for the Department of Energy and Climate Change said: "In the government's recent smart meter consultation we stated our view that a stand-alone real-time display should be provided with a smart meter to empower all consumers to monitor their own energy use and make reductions in energy consumption and carbon emissions as a result.
"We will say more on this in the autumn when we publish our response to the consultation."