Vulnerable groups may not benefit from the installation of smart meters in their homes, according to National Energy Action (NEA).
The charity states that those who are already fuel poor are unlikely to be able to keep their home warm, whether they have a smart meter or not.
Under recently-announced government plans, every home in the UK will be fitted with a smart meter by the end of 2020. It is hoped that by monitoring real time energy usage smart meters will reduce carbon emissions and produce cheaper electricity bills.
Maria Wardrobe, director of communications at the NEA, said: "Smart meters may bring financial benefits to energy suppliers and more affluent customers, but the advantage to vulnerable and fuel-poor people is less certain."
She added that they were concerned that the additional information about energy use provided by smart meters may lead to people turning their heating down too low to heat their house.
The group Consumer Focus has already expressed concerns that the cost of providing smart meters and green energy technology will be passed on to customers who are unable to afford it.
Consumer group Which? recommends comparing and switching energy supplier as a good way of reducing gas and electricity bills.
Click here to run an energy price comparison, and see if you could be paying less for your gas and electricity.