How it works
This is the physics equation with the most direct line to your bank account. Every appliance's cost is just power (kilowatts) × time (hours) × price (per kWh). No exceptions, no fine print — thermodynamics writes your electricity bill.
The heavy hitters are always the devices that make heat or move it: heaters, boilers, tumble dryers, ovens, saunas. A 2 kW heater running 3 hours a day costs more per year than every light bulb, phone charger and router in the house combined — usually by an order of magnitude.
The practical strategy falls straight out of the physics: attack high-wattage × long-hours devices first. Cutting one hour of daily heater use saves ~150 €/yr at 0.20 €/kWh; obsessing over standby LEDs saves cents. Physics tells you where the money actually is.
Use it in real life
Household budgeting: run this for your five most-used appliances and you'll know your electricity bill's anatomy better than most energy consultants would tell you.
Purchase decisions: an efficient heat-pump dryer costs more upfront but at ~half the kWh per load, the physics pays the difference back within a few years — you can compute exactly when.
Heating choices: a heat pump moving 3 kWh of heat per 1 kWh of electricity beats any resistive heater by a factor of ~3, always. That's a thermodynamic fact, not a sales pitch.
Frequently asked questions
What uses the most electricity in a home?
Heating and cooling (space heating, water heating, air conditioning) typically dominate at 50–70% of consumption, followed by tumble dryers, ovens and refrigeration. Anything that creates or moves heat is expensive; electronics are usually minor.
Is standby power worth worrying about?
Modern standby is ~0.5 W per device — under 1 € per device per year at typical prices. A whole house of standby devices costs less than one week of a 2 kW heater's 3-hour daily habit. Fix the big physics first.
How do I find an appliance's wattage?
Check the label or spec plate (usually on the back/bottom), the manual, or use a plug-in energy meter for the real average — devices like fridges cycle on and off, so their average is far below their peak rating.