What This Calculator Does
Select a household appliance, enter the hours per day you use it and your electricity rate, and the calculator returns the running cost per day, per month, and per year — alongside the energy consumption in kWh. Wattage is auto-filled from a typical preset for each device and can be overridden at any time.
This is the only tool on AixKit that takes you through the complete flow in one step: appliance → auto wattage → kWh → cost in your currency. For kWh only (no cost), use the Appliance Energy Calculator.
How Running Cost Is Calculated
Two formulas run in sequence:
- Energy: (Watts × Hours) ÷ 1,000 = kWh per day
- Cost: kWh per day × rate = cost per day
Monthly and annual figures are daily cost × 30 and × 365 respectively. The calculator works in any currency — enter your rate in the same unit as your electricity bill (pence, cents, euro cents, etc.) and the result will match.
Worked Examples
Example 1 — Air conditioner (1,500 W, 8 h/day, £0.29/kWh):
(1,500 × 8) ÷ 1,000 = 12 kWh/day → 12 × 0.29 = £3.48/day → £104.40/month. For a model that accounts for AC type, tonnage, and inverter efficiency, see the AC Electricity Cost Calculator.
A single window AC unit is typically the largest single cost in a summer electricity bill.
Example 2 — TV (100 W, 5 h/day, £0.29/kWh):
(100 × 5) ÷ 1,000 = 0.5 kWh/day → 0.5 × 0.29 = £0.145/day → £4.35/month
TVs are cheap to run compared to heating and cooling. Standby draw adds a small constant cost.
Example 3 — Refrigerator (150 W rated, cycling):
At rated wattage (24 h): (150 × 24) ÷ 1,000 × 0.29 = £1.04/day — but it cycles.
Realistic (60 W effective): (60 × 24) ÷ 1,000 × 0.29 = £0.42/day → £153.30/year
The cycling warning appears automatically when you select Refrigerator or Washing Machine.
What Affects Appliance Running Cost
- Wattage — the single largest variable; a 3,000 W central AC costs twice as much to run as a 1,500 W window unit per hour
- Usage hours — directly proportional; one extra hour of electric heating per day adds ~£21/year at £0.29/kWh
- Electricity rate — varies by country, supplier, tariff, and time-of-use; night-rate tariffs can be 30–50% cheaper for EV charging
- Cycling behaviour — cycling appliances draw rated wattage for only part of their “on” time; using full rated wattage overestimates cost
How to Reduce Appliance Electricity Cost
- Reduce usage hours — turn off heating or AC when rooms are empty; each hour avoided is an immediate cost saving
- Choose energy-efficient models — inverter ACs and A+++ rated appliances use significantly less power at the same output
- Adjust temperature settings — dropping AC target temperature by 1°C typically increases consumption by 6–10%; raising heating setpoint has the same effect in reverse
- Avoid standby consumption — plug off devices at the socket when not in use; standby draws of 2–5 W across multiple devices add up over a year
Electric heaters are among the highest single-wattage devices in any home. For a heater-specific linear cost model with type presets, use the Heater Electricity Cost Calculator.
How This Differs from Other Calculators
Three tools, three scopes — choose the one that matches your question:
- Appliance Energy Calculator: kWh only, no cost. Best when you just need to understand energy usage without a tariff.
- Electricity Cost Calculator: you supply any wattage manually. Best when you have a spec-sheet or smart-plug value and need a precise cost figure.
- This calculator: appliance → preset wattage → kWh → cost. Best for a quick real-world running cost estimate without looking anything up.
Important Limitations
- Preset wattages are estimates: actual draw varies by model, load, settings, and age. For the most accurate cost, check the wattage label or EU/UK energy rating, or use a plug-in energy monitor.
- Cycling appliances: refrigerators and washing machines do not run at full wattage continuously. The cycling warning advises halving the preset. Your appliance’s annual kWh from its energy label gives the most reliable figure.
- Electricity rate varies: rates change by time of day, supplier, and billing period. Use the rate from your most recent electricity bill for the most accurate comparison.
