Air cooler (evaporative): units per month in Pakistan
Short answer. An evaporative air cooler draws around 190 watts — roughly a tenth of a 1.5 ton air conditioner. Nine hours a night is about 1.7 units a day and 51 units a month, which is why a cooler remains the cheapest real cooling available to most Pakistani households.
Power draw
- Low: 120 W
- Typical: 190 W — the figure used in every calculation below
- High: 300 W
Fan motor plus water pump. Larger desert coolers with a bigger blower sit at the top of the band.
Units and cost by usage pattern
Each row is 190 W × the hours shown ÷ 1,000, over 30 days. The three cost columns exist because the rupee cost of a unit depends entirely on which slab your month lands in — the same consumption costs a light user and a heavy summer household very different amounts. Rates are illustrative and not a substitute for the tariff table printed on your own bill.
| Usage pattern | Units / day | Units / month | At Rs 12.5/unit | At Rs 27.5/unit | At Rs 36/unit |
|---|---|---|---|---|---|
| Bedroom, night (9 hours) | 1.71 | 51.3 | Rs 641 | Rs 1,411 | Rs 1,847 |
| All-day use in a shop or courtyard (14 hours) | 2.66 | 79.8 | Rs 998 | Rs 2,195 | Rs 2,873 |
Rate bands: Rs 12.5 — light user, protected (≈150 units/month); Rs 27.5 — average household (≈250 units/month); Rs 36 — heavy summer month (700+ units). This appliance is seasonal — the usage patterns above assume 4 months of the year at most, so the annual figure is lower than twelve times the monthly one.
Where it works and where it does not
Evaporative cooling works by turning water into vapour, which requires dry air to absorb it. In Multan, Bahawalpur, Sargodha or Quetta during the dry pre-monsoon heat, a cooler can drop air temperature by eight to twelve degrees.
In Karachi, Hyderabad or Lahore during monsoon humidity, it drops the temperature by two or three degrees and adds moisture to a room that is already saturated. The same machine that is excellent in May in Multan is close to useless in August in Karachi.
It needs an open window
A cooler must exhaust the humid air it produces, which means a window or door open on the far side of the room. Sealing the room, as you would for an air conditioner, makes a cooler progressively worse as the air saturates.
This is the single most common installation mistake, and it turns a working cooler into an expensive humidifier within an hour.
The water cost
A cooler evaporates several litres an hour. Where water is pumped from a bore, that pumping is a real electricity cost that belongs in the comparison, though it remains small beside an air conditioner.
How to use less
- Keep a window open on the opposite side of the room — it is a requirement, not an optimisation.
- Replace the cooling pads each season; compacted pads reduce evaporation and the fan then just moves warm air.
- Run the pump only when the pads are being used; on humid days the fan alone is often the better setting.
- Position it to draw outside air rather than recirculating room air.
Frequently asked questions
How much cheaper is an air cooler than an AC?
About ten times, on power draw — roughly 190 watts against 1,800. On a monthly basis, a cooler running nine hours a night costs around 51 units against about 300 for a comparable air conditioner schedule.
Can an air cooler work during load shedding on a UPS?
Yes, and it is one of the few genuinely useful cooling loads for a domestic inverter. At around 190 watts a modest battery bank can run one for several hours, which is not true of an air conditioner.
Compare with
- Air conditioner (1.5 ton, non-inverter) — 1800 W typical
- Ceiling fan — 65 W typical
- Exhaust fan — 45 W typical
- UPS / home inverter — 180 W typical
Filed under cooling in the full appliance index. Add your own hours in the consumption calculator, or open your actual bill with the reference number lookup.