The financial journalist told listeners of his BBC podcast about how they could slash their bills by turning down the setting on their boiler. He also recommended people take the Money Saving Boiler Challenge, which could save the average household some £112 a year.
He said: “If you have a gas combi boiler, which is the type most homes have, the flow rate on most of those boilers are set too high as a default.
“The flow rate is the temperature of the water that circulates around the system. If it’s too high, the boiler isn’t operating to maximum efficiency.
“Changing your flow rate can cut gas bills by over nine percent and you won’t notice the change.”
Mr Lewis assured viewers the quality of their heating would be unaffected by the change.
He said: “Your hot water and heating will all be unchanged.
“They might take a tiny bit longer to heat up but go and take the Money Saving Boiler Challenge, which will give you step-by-step instructions on what to do on your boiler.
“I’ve been talking about this for six weeks or so and lots of people say it’s made a big difference, and they don’t notice it.
“So it changes your bills, it doesn’t change your home.”
The Money Saving Boiler Challenge is completely separate from Money Saving Expert, which Mr Lewis founded.
The challenge encourages Britons to turn down the flow temperature on their combi boiler to 60C or below, as this can “knock pounds off your heating bill each year and reduce energy waste from your home”.
The flow temperature is the temperature a boiler heats water to before it goes around the radiators of a property.
Reducing the flow temperature will not affect the temperature of the hot water that comes out of a household’s taps and showers.
The Energy Price Guarantee came into effect at the start of October, capping the price of energy but still meaning bills rose significantly, to on average £2,500 a year, for typical households.
Appliance brand Hisense offered some tips to help Britons better understand how their household appliances use energy and how they can reduce the energy needed to run them.
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The appliance which typically uses the most electricity per household is the refrigerator, as the fridge has to be constantly powered.
A Hisense spokesperson said: “By ensuring your refrigerator appliances are set to the optimum settings, and not leaving the door open for longer than necessary, as this makes the motor work harder to stabilise the set temperature, are just a couple of small ways in which you can make a big difference.
“The way you arrange the items in your fridge can also help; for example, we’d advise avoiding any foods touching the back of the fridge to help regulate the temperature and airflow.”
Added extras on fridges and freezers such as ice dispensers can impact the amount of energy the appliances use.
The company said: “The main bulk of the energy usage goes to keeping the temperature of the fridge freezer cool and regulated.
“Having access to an ice dispenser also means that for some households this will reduce the amount of freezer space required, meaning that they don’t need to run an additional appliance.”
For appliances such as washing machines and dishwashers, Hisense says the amount of energy used can be influenced by the setting that someone uses.
The group said a full 10kg load of washing set to 39 degrees on a four-hour cycle will use 0.99kwh energy.
This compares to a full load of a 10kg washing machine, set to 20 degrees on a 129-minute cotton cycle, which will only use 0.22kwh energy. With the current kwh cost being 34 pence, 0.22kwh equals 7.5 pence.