10 mistakes adding £100s to your energy bill

Last updated: October 1, 2024

With the weather turning colder and the heating on more regularly, you might be concerned about what this could do to your winter energy bills.

In August, it was announced that the energy price cap would rise by 10% from 1 October 2024, which comes after two reductions to the cap earlier in the year. Ofgem estimates this will mean an extra £149 added to the average energy bill – however this amount will vary based on your EPC rating, and the type of home you live in.

So many of us might be looking for ways to reduce our bills, especially at this time of year. And there are some common mistakes and easy-to-alter habits that collectively, could be adding hundreds of pounds* to our bills.

Take a look…

Not fixing draughts
Adding to your bill each year: £40

Fixing draughts is one of the most cost-effective changes you can make in your home. Draught-proofing steps you could take include adding foam strips around your windows if you can feel they’re letting air in.

Your external doors could also be letting cold air in and warm air out, so things like a metal cover for your keyhole, a brush cover for your letterbox, or a draught excluder (a homemade one would work fine) for the base of the door can really help.

If you have a room with an unused fireplace, you could be getting a draught down your chimney – there are chimney draught excluders available if this sounds like you.

When draught-proofing, you just need to make sure that rooms that produce a lot of moisture, such as your kitchen or bathroom, are still kept well ventilated, as well as not blocking any vents that help with air flow.

Setting your room thermostat too high
Adding to your bill each year: £90

If your thermostat’s set at a high temperature, your heating won’t turn off until the thermostat recognises that your room has reached this temperature, and turning a room thermostat up won’t make the room get hotter more quickly than if it was on a lower setting. So in short, your rooms might be getting much hotter than is comfortable, or than you need them to be.

Turning your room thermostat down by just one degree, from 22 to 21 degrees, could save you £90 a year.

You could test a lower temperature to see if you’re comfortable with your rooms cooler than that, too: turning your thermostat down to 18 degrees from 21 degrees could save you £260 a year.

Setting your boiler flow temperature too high
Adding to your bill each year: £30

If you have a gas boiler, it will have a control that lets you adjust the temperature of the water that flows through your home’s radiators. This is called the flow temperature.

Combi boilers will have two controls: one for the hot water that comes out of your taps, and one for your radiators. A boiler that’s running at a lower temperature will run more efficiently than one set to its maximum heat. So you could try altering the temperature of your radiators to a setting that’s lower, as long as you’re still comfortable.

It’s important to note that, if you have a conventional boiler and a hot water cylinder, you won’t be able to lower your flow temperature to anything lower than 65 degrees. This is because set any lower, bacteria could start to grow in the cylinder.

Not insulating pipes, and hot water tank if you have one
Adding to your bill each year: £45

First off, insulating your pipes can be a good idea as it prevents them from freezing, and potentially bursting, when the temperature drops below freezing.

There are multiple low-cost pipe insulation options available, including foam, rubber, and foil tape, which come in different thicknesses.

Insulating a hot water tank helps keep the water inside hotter for longer, and you’ll need to use less energy to keep it at a high temperature, too. Even if you have some tank insulation, adding an extra hot water jacket could save you £40 a year, while adding insulation to all of your exposed pipes could save £5.

Washing clothes at too high temperatures
Adding to your bill each year: £12

Modern laundry detergents are designed to wash clothes effectively at lower temperatures, so you might find that for some loads, you’re able to switch from 40 to 30-degree washes. This will use less energy per cycle, and could save you £12 per year.

Leaving appliances on standby
Adding to your bill each year: £45

Leaving your TV on standby overnight, or a charger plugged into a power outlet might seem like it would only use a tiny amount of energy. But, added up over the course of a year, this can add £45 to your annual bill.

Leaving curtains open
Adding to your bill each year: £20

Believe it or not, not closing your curtains can add over £20 to your bill annually, as well as saving almost 60kg of carbon each year – equivalent to a 200-mile car journey. This is because the curtain’s fabric traps the warm air in the room, and can help prevent draughts.

If you have a radiator underneath a window, make sure the curtains don’t cover the radiator while your heating’s on, otherwise the heat won’t be distributed around the room.

Having old halogen light bulbs
Adding to your bill each year: £40

Lighting typically accounts for over 10% of your home’s electricity usage, so making energy efficient changes can have a big impact on your bill. If you have old halogen bulbs throughout your home, you might not know that most of the energy used to power these is ‘wasted’ heat, rather than light. And you could be paying £40 more a year than if you switched to low-energy LED versions.

Ignoring the energy label rating when buying new appliances
Adding to your bill each year: up to £65

Similar to the EPC ratings you’ll find on many property listings that show how energy efficient a home is, lots of everyday electrical appliances have energy ratings, too. They work in a similar way to EPCs, with G ratings for the most inefficient products, and A or even A+++ ratings for the most efficient appliances, which cost less to run. Switching from an E-rated freezer to a D-rated version could save you £30, while a B-rated tumble dryer can cost £65 more to run each year than one with an A+++ rating.

Not having a smart meter
Adding to your bill each year: around £40

While a smart meter doesn’t reduce your energy on its own, it can be a really useful way of monitoring your home’s energy usage. You can apply for one for free from your energy supplier, and it will show you how much power you’re using, broken down by gas and electricity. You might see your usage spiking when you’re using particular appliances around your home, which encourage you to use them less.

Energy Saving Trust estimates that it could reduce a typical gas bill by around £16 a year, and electricity usage by around £25.

* Individual savings estimates are provided by Energy Saving Trust. Total savings may vary based on the number of changes you make, and the order in which you make them. These costs looked at the average savings for a typical three bedroom semi-detached gas heated home, using an average gas price of 6.2p/kWh and an average electricity price of 24.5p/kWh. Correct as of October 2024.

What else can you do to save money on your bills this winter?

We’ve got lots of simple energy saving tips you can make right now, as well as larger long term measures that could help save money over the long term, improve your home’s EPC rating, and reduce its impact on the environment.

You might be wondering whether you could reduce your bills by switching to a different energy supplier, or locking in a better deal with your existing supplier. Our calculator will show you energy quotes bespoke to your household, including how much you could save.

READ MORE: Check our energy bill tracker to see average bills by EPC rating and property type