Consumers could save £336 a year – more than £3,000 over a decade – on their energy bills and help reduce their carbon footprint just by switching to more energy-efficient appliances when their old white goods need replacing, according to a study by consumer watchdog Which?

The consumer champion’s newly-launched running cost tools aim to help people save money on their bills by calculating the energy efficiency of tumble dryer, washing machine, fridge-freezer, oven and dishwasher models Which? has tested against the energy price cap.

The least efficient models in each category would collectively cost £490 a year to run, claims Which? Consumers could save £336 annually by opting for the most energy-efficient appliances – which cost just £154 a year to run.

Which? energy cost data comes from independent lab testing and is based on real-world scenarios. It often reveals big differences between A-rated machines, and that in some cases B and C-rated machines can actually cost less to run.

While some of the most efficient appliances may be more expensive up front, Which?’s research has found they are cheaper over the average product’s lifetime due to their lower running costs.

For example, the most energy-hungry vented tumble dryer Which tested costs £260 to buy while the most energy-efficient, costs £800.

However, the most energy-efficient tumble dryer costs just £29 a year to run – if drying roughly three loads a week – compared to £135 for the other model. Factoring in the cost of both tumble dryers, consumers would save £1,580 over the course of the appliances’ lifetimes if they opted for the most energy-efficient machine due to its lower running costs.

Heat pump tumble dryers tend to be both more energy efficient and pricier than cheaper condenser and vented models but can easily pay for themselves in energy savings, said Which? On average, condenser dryers cost £109 per year to run while heat pump models cost just £42.

Consumers also stand to make big savings by choosing carefully when they buy their next fridge-freezer. The least energy-efficient fridge freezer tested, costs £134 in energy bills a year. People could cut this cost by £104 by a more energy-efficient model, which runs up just £30 in annual energy bills, claimed Which?

The type of fridge-freezer people opt for will also have an impact, said Which? On average, a freestanding fridge-freezer will add around £61 per year to people’s energy bills, while a large American-style fridge-freezer will add around £92 per year.

Consumers could also save £55 a year by choosing a more energy-efficient washing machine when they need to replace their existing model. On average, a washing machine will add £46 per year to people’s bills, but running costs can vary from under £20 to as much as £70 per year if running four 40°C washes per week.

Washing machines which use more energy tend to wash better, the research found. Which?’s Eco Buy reviews highlight the products which are long lasting, energy and water efficient and easily repairable, while still doing their job well.

Ovens are not typically as energy-hungry as other large appliances such as fridge-freezers or tumble dryers, but it is still worth checking out their energy-efficiency before buying, said Which? On average a built-in oven costs £53 a year to run.

Which? is advising consumers who are looking to cut their energy bills to use its running cost tools to check the efficiency of appliances before purchasing new white goods.

While many white goods already come with an energy efficiency rating, Which?’s surveys have found that UK consumers use appliances differently from the official rating tests. For example, the ratings for washing machines are mostly based on washing at 60°C, but most people wash at 40°C.

The consumer champion’s running cost tools calculate the energy efficiency of appliances based on how consumers have told Which? they use their white goods. However, as the tool only looks at the energy efficiency of appliances, Which? is advising people to check its Eco Buy reviews to ensure the appliance they choose is high performance and offers the best possible value for money.

Lisa Barber, Which? home products and services editor, said: “Choosing the right appliances for your home could cut hundreds of pounds a year from your energy bills and reduce your environmental impact. This is crucial at a time when most of us are already facing higher energy bills and having to tighten the purse strings.

“Which?’s running cost tools allow consumers to easily compare the energy efficiency of popular household appliances – helping them buy better and choose the best product in the long run.”