Is it cheaper to have a bath or a shower? Your energy questions answered | Energy bills

With energy bills on everyone’s mind, those little questions about how to cut your use have come to the fore. We asked experts to answer some FAQs.

Is it cheaper to boil water for pasta in an electric kettle or a pan on a gas hob?

The million-dollar question. Brian Horne, a senior insight and analytics consultant at the Energy Saving Trust, says a kettle is more efficient than a hob for heating water as it is heated from the inside, whereas the pan is heated from the outside and needs to get warm first. Kettles will boil water faster and use fewer units of energy. But while gas hobs take much longer and use up to three times more energy in unit terms, the consumer group Which? says that because gas is cheaper than electricity (less than a third per unit), it works out slightly cheaper to boil water on a gas hob than using an electric kettle. This assumes you are boiling only the quantity you need, are using a lid and switch off the hob as soon as it has boiled.

Have you considered how much it costs when you boil pasta? Photograph: Delihayat/Getty

Am I wasting energy by leaving my phone charger plugged in?

Yes. British Gas estimates that as much as 23% of our electrical usage, or £200 a year currently, could be put down to what are being termed vampire devices – chargers left plugged in and switched on or items on standby. Hi-fis, televisions, set-top boxes and games consoles that sit on standby are all using power – and the older the device, the greater the standby load. However, it is also the unseen chargers, such as those for electric toothbrushes, razors, etc. “As soon as your device is fully charged, try to get into the habit of unplugging it,” says Marc Robson, a British Gas smart energy expert. “As well as saving energy, this will prolong your battery life. And it could also save you about £60 a year on your electricity bills.”

White smartphone charging on a charging pad.
Do you charge your phone for longer than is necessary? Photograph: Daniel Jedzura/Alamy

Are electric or gas hobs cheaper to cook on?

Gas, because the unit price is far less than the unit price of electricity. This is partly offset if you have an induction hob. “If you’re looking to reduce your carbon emissions, consider using an electric or induction hob rather than gas,” Horne says. “Induction hobs are typically the most energy-efficient as no energy is wasted heating space around the pan.”

Whichever you use, Robson says you can cut energy use by some careful choices: “Use the right size of saucepan for what you’re cooking and fill it with just enough water. Putting a lid on will save energy and reduce condensation in the kitchen, too.”

Should I microwave soup rather than using a hob?

If you are reheating food, microwaves are more efficient than electric and gas ovens, Horne says. “Comparing a microwave with a hob is trickier, though – the microwave is likely to use the least energy but a gas hob may still be cheaper.”

Can I wash my clothes properly at less than 40C?

Yes. “Modern washing powders and detergents work effectively at lower temperatures,” Horne says. Brands such as Ariel and Persil advertise that their products work at 30C. None seem to make claims about washes below that. However, Which? says its tests found “cleaning power was slightly worse at 20C compared with 40C” but “switching to a liquid detergent helped, and should still be enough for everyday cleaning”.

Clean washing coming out of a washing machine into a basket
Laundry detergent brands such as Ariel and Persil advertise that their products work at 30C. Photograph: Lynne Sutherland/Alamy

Just moving the dial down to 30C will make a big difference to the cost of running a washing machine – Horne says it will cut the energy needed by 40%. Robson adds: “Spin your clothes before hanging them out to dry, instead of relying on your tumble dryer.”

Should I keep my house at a constant heat or let it cool down and warm up?

You will always save money by turning the heating off when you don’t need it, Horne says. It will take extra energy to heat up when you turn it back on but this will always be less than the energy wasted by running the heating when you don’t need to. He says the only exception is if you have a heat pump, as these are more efficient if you leave them running for longer at a lower output.

Martyn Bridges, the director of technical support at the boiler maker Worcester Bosch, agrees: “It is generally more economical to turn off your heating system when you are not so much in need of it. For example, through the night or parts of the day when the house is empty.”

Does it always make sense to turn lights off when you leave a room?

Traditional lightbulbs and modern LED lights don’t take any extra energy to turn on, so you should always turn them off when you are not using them or when you leave a room, Horne says. He says this could save you about £20 a year.

Robson says LEDs are so energy-efficient that it won’t make much difference to your bills if you leave them on for five minutes when you pop out of the room “but we always advise turning them off anyway, so that you get into good habits”.

If you do still have any traditional lightbulbs, switching them for LEDs will result in a 69% energy saving.

Is it cheaper to have a bath or a shower?

Close-up of a rubber duck
Is a long, hot bath the most economical option? Photograph: Michele Adamson/Getty

A short(ish) shower. Worcester Bosch’s Bridges says: “A typical bath requires about 90 litres of water, split between 60 litres or so of hot water and 20 to 30 of cold. A normal thermostatic mixer shower head discharges about nine litres a minute, requiring about six litres of hot and three litres of cold. So, providing you shower in less than 10 minutes, it will be more economical to shower.”

https://www.theguardian.com/money/2022/mar/29/cheaper-bath-shower-energy-questions-answered-reduce-bills