There is one rule that explains almost an entire electricity bill: things that make heat cost money, and things that make light or sound do not. A kettle draws more power in two minutes than an LED bulb does in a day. A tumble dryer costs more per cycle than a television costs in a month.
Once that is clear, the ranking of what to change becomes obvious, and it looks quite different from the standard advice list.
The tumble dryer is the biggest routine cost
A tumble dryer heats a large volume of air and runs for an hour or more, several times a week. It is comfortably the most expensive habitual appliance in most homes with one, and it is also the easiest to stop using.
A clothes airer costs very little and pays for itself within a handful of loads. In winter, drying indoors adds humidity you may need to ventilate — but that is a matter of opening a window, not of running a dryer.
Washing temperature
Around 90 percent of a washing machine's energy goes into heating the water rather than turning the drum. Dropping from 40C to 30C therefore cuts the cost of a load substantially, and modern detergents are formulated to work at 30.
The kitchen
- Boil only what you need. A kettle's cost scales directly with the volume of water. Filling it for one mug rather than four is a real saving repeated several times a day.
- Put lids on pans. An uncovered pan loses most of its energy as steam. A lid roughly halves the energy needed to hold a simmer.
- Use a microwave or air fryer for small portions. Heating an entire oven cavity to bake two potatoes is one of the least efficient things a kitchen does.
- Let hot food cool before it goes in the fridge, and keep the freezer reasonably full — thermal mass helps it hold temperature between compressor cycles.
The standby question
Standby power is real and it is smaller than its reputation. Modern regulations cap standby draw for most consumer electronics at a very low level, and a phone charger left plugged in with nothing attached draws close to nothing.
It is still worth switching off a cluster — a TV, console, soundbar and set-top box on one switched extension — because together they add up. It is not worth crawling behind furniture nightly for a phone charger, and framing it as the main lever distracts from the dryer.
Find your own baseline
Generic advice only goes so far, because every household's biggest waste is different. The diagnostic is straightforward and free: read the meter last thing at night and first thing in the morning. That overnight figure is your always-on baseline — everything running while nobody is using anything.
If that number is higher than a fridge, a freezer and a router can explain, something is running that you have not accounted for. An immersion heater on a timer and an old chest freezer in a garage are the two usual culprits.
What is worth spending money on
In rough order of payback: draught proofing (cheapest, fastest payback), loft insulation, LED bulbs if any remain, then glazing, heating system upgrades and solar. Appliance replacement rarely pays back on energy alone unless the existing one is genuinely ancient or failing.
The short version
- If it makes heat, it costs money. Start there.
- Air dry laundry — the single biggest habitual saving in most homes.
- Wash at 30°C, with one hot cycle a month to keep the machine clean.
- Boil only the water you need, and put lids on pans.
- Switch off standby clusters; ignore the phone charger.
- Measure your overnight baseline before buying anything.
On the kitchen side, how to descale a kettle is a small related win — a furred element has to run longer to boil the same litre.
