ENERGY firms are heavily promoting smart meters as a way to save cash, but they may be the real financial beneficiaries, while customers miss out on far more effective ways to slash their bills.

The devices, which are installed by providers in place of traditional gas and electricity meters, use the mobile phone network to automatically relay usage data, doing away with the need for estimated bills and manual readings.

They also communicate with an in-home display that shows the householder exactly how much power is being used, in theory helping them spot ways to cut back.

However, according to Government figures quoted in a report by the British Infrastructure Group - a committee of MPs and peers - the average annual saving per customer for gas and electricity combined is likely to be just £11.

Meanwhile, the new meters may actually boost suppliers’ profits by encouraging people to remain on uncompetitive tariffs rather than shop around for cheaper options.

Georgie Frost, consumer advocate at GoCompare Energy, explained: “Because smart meters are installed by your current energy provider, there is a danger that customers feel tied to that provider once they have the meter installed.

“This will only be reinforced by the report’s finding that half of all smart meters ‘go dumb’ when the customer switches to a different provider.”

According to the Energy Saving Trust, making a few small changes around the home can produce far more significant savings than simply installing a smart meter.

Turning down the thermostat by a single click from, say, 22 to 21 degrees could reduce costs by £75 a year, while programming heating and hot water to come on only when needed, rather than running them all day, might save £150.

Leaving electrical equipment on standby wastes money as devices use power even when they are not charging or operating. Switching them all off at the wall could cut costs by £80.

Boiling only the amount of water needed in the kettle, washing clothes at 30 degrees, rather than 40 or 60, and putting on the tumble dryer only when the weather is too bad to hang washing outside might save a further £33.

Replacing less efficient halogen lightbulbs with LEDs could cut annual electricity consumption by a further £40.

However, the single most effective way to lower power bills is to change to a less costly tariff or supplier.

Ms Frost said: “Faced with a potential saving of £11 a year by sticking with your smart meter provider, or saving £210 by switching to a better deal, the smart move currently must be to switch provider.”

Customers languishing on the big players’ standard variable tariffs (SVTs) typically have most to save, especially since the latest round of price increases.

This week British Gas announced its second rise of the year, meaning its SVT customers can typically expect to pay £104 more than they did in 2017.

Energy switching service Look After My Bills calculates that the average customer on ScottishPower’s SVT will pay £63 more this year than last, while the rise at SSE is £76, at EDF is £86, at Npower is £64 and at E.ON is £85.

Even those on cheaper fixed-price tariffs are not safe from increases.

According to price comparison site Compare the Market, 169 fixed deals run out between the start of July and the end of September this year, affecting 588,000 households.

Peter Earl, the website’s head of energy, said: “It is easy to forget about your energy bill during the summer months, particularly with record-breaking temperatures hitting the nation.”

Those who do not immediately switch to a new deal will be automatically moved onto their supplier’s SVT, adding considerably to their annual costs. The 392,000 consumers with tariffs ending in August face the highest average hike of £268.

Ms Frost added: “Energy price rises seem suspiciously common around this time of year, as we are about to start needing to use more energy to light and heat our homes. While prices have been rising, there’s no need to sit by and accept it.

“It takes a matter of minutes to compare deals and sign up to a new tariff using a comparison website, and if you’re switching supplier, your new provider will keep you informed throughout the process.”