Annual cost of running air conditioning based on usage.

Air conditioning is one of the highest-draw household appliances. Typical domestic split-system AC: 1,000-2,500W. Portable units: 1,500-3,000W. Running for 8 hours during summer on a 2kW unit: 16 kWh/day × 24p/kWh = 3.84/day. Across a 3-month summer, that's 346. Adding up quickly.

Energy efficiency varies significantly. A-rated inverter AC can use 40-60% less electricity than older fixed-speed units for same cooling output. Upgrade from old to efficient AC can halve running cost — sometimes paying for itself within 3-5 summers of heavy use.

Target room matters too. Cooling one bedroom at night differs from cooling whole-house 24/7. Budget for actual usage pattern, not theoretical maximum.

How to use it

Input AC unit wattage (check unit label or manual), daily hours of use, days per year (summer only or year-round), and electricity rate. The tool shows running cost.

What the result means

Running cost is electricity spend for AC use. Daily figure useful for short-period planning. Annual for overall budget. Compare to alternatives — fans cost 80-95% less and cool effectively for moderate heat.

Quick example

With ac wattage of 1,800 and hours per day of 8 (plus days per year of 90 and rate per kwh of 0.24), the result is 311.04. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.

Which inputs matter most

You enter AC Wattage, Hours Per Day, Days Per Year, and Rate per kWh. Frequency and unit price pull the total in different directions. The biggest surprise for most people is how small recurring amounts compound into large annual figures — that's where this calculation earns its keep.

What's happening under the hood

Wattage × hours × days ÷ 1,000 = kWh. Times rate = cost. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.

Why run the calculation

Utility bills creep. Small annual increases stack into meaningful differences over a decade. Running this once a year and switching providers when the gap widens is one of the easiest ways to keep household costs in check.

What this doesn't capture

Usage varies month-to-month; tariffs change; discounts come and go. The figure here is a clean baseline — your actual annual bill will fluctuate around it. Use the calculation to benchmark providers, not as a prediction of a specific bill.