AC Electricity Cost Calculator for Dubai and the UAE

An air conditioner is rated in BTU of cooling. What you pay for is kilowatts of electricity. EER is the number that connects them.

EER means energy efficiency ratio. It is the BTU of cooling you get for each watt of electricity you put in. So a unit doing 12,000 BTU at an EER of 10 draws 1,200 watts, which is 1.2 kilowatts.

Multiply that by the hours it runs and you get kilowatt hours, which is what the bill charges for. Multiply by your rate and you have the cost.

So the whole chain is: BTU divided by EER gives watts, watts times hours gives kilowatt hours, kilowatt hours times your rate gives AED.

That is why EER matters so much. The same cooling at EER 14 instead of EER 8 costs almost half as much every single hour.

This is the number the tool cannot guess for you, and it is worth two minutes to get right.

Look at your electricity bill. There will be a consumption figure in kWh and a charge for electricity. Divide the charge by the kWh and you have your effective rate.

Do it that way rather than reading one number off the tariff table, because charges are billed in bands and most bills also carry other line items. The number you actually care about is what one more unit of electricity costs you, and dividing the bill gets you close to it.

If you are in a villa with high summer usage, work it out from a summer bill rather than a winter one. Your effective rate in August is usually higher than in January, because more of your usage falls in the upper bands.

Once you have that number, save it. Every energy tool on this site uses the same one.

This is where most people get their estimate wrong, and it goes both ways.

A thermostat does not run the compressor all the time. It cools until the room reaches the set temperature, then the compressor stops while the fan carries on. So a unit switched on for twelve hours might only be cooling for seven of them.

In a Dubai August, though, that gap almost closes. On a hot afternoon a correctly sized unit runs nearly continuously, because the room gains heat as fast as the unit removes it. That is not a fault.

So use different numbers for different times of year. In summer, the hours you have it on and the hours it is cooling are close to the same. In winter they are not.

An inverter unit muddies this further, because it slows down instead of stopping. It is running most of the time but drawing much less than its rated power. For an inverter, the honest way to use this tool is to put in fewer effective hours than the clock says.

In rough order of how much difference each one makes over a UAE summer.

Use it to compare, not to predict your exact bill.

It is very good at showing you the difference between two choices. Run it at 21 degrees worth of hours and again at 24, and the gap is real. Run it at EER 8 and again at EER 12 and you can see what a new unit would save.

It is less good at predicting a whole bill, because a home has a fridge, a water heater, lights and everything else, and because your rate moves as your usage moves through the bands.

For a whole year, including the servicing that keeps the unit efficient, use the running cost calculator instead. This one is about the electricity alone.