Use the correct wattage
Prefer the published cooling power input for the exact model. Cooling capacity in BTU/h or kW describes heat removal and is not the electrical input to enter. Do not substitute a retailer's generic range.
TONIGHT'S SCENARIO
Can I cool my bedroom for £1 tonight?
Use your own tariff and a product's verified electrical input. The result is an estimate, not a promise about compressor cycling.
ESTIMATED TONIGHT£1.17
4.68 kWh. This entered scenario is above £1.
Actual cycling changes with weather, room heat gain, set point and installation.What changes the result?
Room heat gain, set temperature, outdoor conditions, hose sealing and compressor control all affect cycling. Compare rated maximum input separately from a cycling scenario.
Open the full annual calculator →Keep rated input and likely cycling separate
The price of one night depends on the appliance input, tariff, operating time and how often the compressor actually runs. A single headline figure hides those assumptions.
Run more than one duty case
A full-input case provides a cautious upper scenario. A lower duty cycle can illustrate compressor cycling, but room heat gain, thermostat setting, exhaust sealing and outdoor conditions decide whether that assumption is realistic.
Use the accepted tariff
Enter the unit rate that applies during the operating hours. Keep standing charges outside a marginal overnight comparison unless the decision actually adds or removes an energy account.
Limit: The result is an electricity scenario, not a bill forecast, comfort guarantee or efficiency test. It excludes purchase, maintenance, accessories and unknown tariff changes.
Continue with evidence
Your next checks
Move from the current answer to sizing, evidence and a clear commercial next step.
PARENT TOPICRunning-cost centreReview tariffs and calculation boundaries.DECISION TOOLFull running-cost calculatorModel weekly and annual use.DECISION TOOLCheck tonight's heat riskAdd live outdoor context.GUIDEAC running costs explainedUnderstand watts, duty and tariff.GUIDENoise at nightBalance cost with bedroom comfort.NEXT ACTIONCompare rated inputUse verified product power figures.