How to Cut Your AC Electricity Use in a Delhi Summer

1. Settings: stop cranking it to the lowest number

Setting the AC to its coldest setting does not cool the room any faster. The compressor runs at the same output either way; all a lower setting does is make it run for longer before it rests.

• Hold a comfortable mid-twenties Celsius setting rather than the minimum. Every degree lower means meaningfully more running time over a long night, for comfort most people cannot actually feel.
• Use a high fan speed to cool the room down, then drop it. Moving air across the coil faster gets the room to temperature sooner. Once it is there, a lower fan speed is quieter and enough.
• Use sleep mode or the timer overnight. A room needs less cooling at four in the morning than at midnight, and sleep mode raises the setting gradually so the unit runs less in the coolest hours.
• Do not switch it on and off repeatedly to save power. Every restart is a fresh surge from the compressor, and on an inverter unit you are also cancelling the low-speed running that makes it efficient. For a gap of under an hour, leave it running at a higher setting.
• Turn it off when you leave. Obvious, and it is still the biggest single saving in most homes.

2. Run the ceiling fan with the AC

This is the highest-return habit on the page and the one people resist, because running two things to save power feels wrong. It is not.

• A ceiling fan uses a tiny fraction of what an AC does. Adding it costs very little and lets you hold a higher AC setting for the same comfort.
• Moving air makes you feel cooler at the same temperature. The fan does not cool the room. It moves air over your skin, which is what your body registers as cooler.
• Run it on low. Enough to stir the air. High speed fights the AC’s own airflow pattern and is noisier than it needs to be.
• It evens out the room. A split AC blows from one wall, so corners and the far side of the room stay warmer. A slow fan mixes the air, which stops you dropping the setting to fix a cold spot problem.

3. A dirty AC costs more every single day

This is the Delhi part. Dust does not just make an AC cool badly — it makes it cool badly while drawing the same power, which is exactly how a bill climbs with no change in your habits.

• Wash the filters every two weeks in season. The cheapest efficiency measure there is. Our AC filter cleaning tips cover doing it properly.
• Keep the outdoor unit clear and clean. That is where the heat leaves your home. Boxed in, covered, or caked in grey dust, it cannot shed heat into a 45°C afternoon and the unit simply runs on and on. Our guide on where the outdoor unit should sit covers what it needs.
• Get one proper wet service a year, before summer. A coil washed in March holds its efficiency through the season it has to survive.
• Treat a rising bill as a symptom. If the AC is running longer than it used to for the same room and the same weather, something is choked. That is a service, not a bill you have to accept.
• Do not run it iced up. Frost on the coil means the unit is working hard and cooling poorly at the same time. See our guide on the AC that ices up.

4. Stop the heat getting in

Every bit of heat you keep out of the room is heat the AC does not have to pay to remove. In a Delhi summer this is worth as much as anything you do to the machine.

• Curtains or blinds on west and south-facing windows, closed from noon. Direct afternoon sun through glass is the single biggest heat load in most Delhi bedrooms.
• Seal the gaps. Under the door, around window frames, and the wall hole where the copper pipe enters. Cool air escaping is cooling you paid for.
• Keep the door shut and stop cooling the corridor. An AC sized for one room cannot cool the flat, and asking it to try means it never switches off.
• Move the heat sources out. A desktop, a set-top box, an inverter and chargers all quietly add heat to a closed room. So does an incandescent bulb, where one is still in use.
• Cook, iron and run the geyser outside AC hours where you can. Especially in small flats where the kitchen opens into the cooled space.
• Top floor: deal with the roof. A bare concrete terrace absorbs heat all day and radiates it down into the room till late at night. Shade, a reflective coat or terrace tiling does more for a top-floor flat than any setting change.

For the wider view across every appliance in the house, see our guide on reducing your electricity bill in Delhi, and our summer heat and cooling tips for keeping the flat liveable outside AC hours.