Eid holidays: Should you leave the AC on or off when away?

Do you leave your AC on where you go on holiday? And when you go to work? Do the benefits of a cool house weight up to the electricity bill at the end of the month? Or not?

The decision is tricky if the cooling system in your building is included in the rent. In that case, the bill will never occur to you and you may opt for a cool house in all cases. But you may want to consider energy efficiency.

If you do have to foot the electricity bill, you might even be more aware of the matter, and toss and turn whether you want to save money, energy, or just be comfortable.

“I always turn off my AC; when I go to work and when I go on a holiday. I pay the bill at the end of the month and I prefer to save the money for something else,” said Vanessa Veringer, a Norwegian resident living in Al Nahda.

Mariska van Visseren, a Dutch resident living in Tecom, too says to switch off the AC. However, she does not pay for the service. “I do not see why I would keep the AC switched on when I am not there. When I return home, it takes about 5 minutes for the apartment to be at a comfortable temperature.”

That being said, not all residences are easily cooled and well maintained in high temperatures. A larger structure can take longer to cool down, and requires more than one AC unit.

Further, some people complain of the accumulation of mould whenever the AC remains switched off. “I always keep my AC switched on. When I leave the house for 7 hours without the air conditioning, I find water on the floor, fog on the windows, and the upper floors have a mouldy smell to it,” says Vashna Kapoor, an Indian resident living in Bur Dubai.

Going on a holiday

“For sure, there is a risk when you switch off the AC for a long period of time,” said Stephane Le Gentil, CEO of Etihad Esco, a Dewa venture specialising in energy efficiency. “You do save money and energy, but you may face damage in your home.

“There is not really an optimal solution to this question. It depends on the time you are away, on the property, and on the items kept inside the property,” he added.

Colin Summers, Managing Partner at maintenance firm Jim Will Fix It, describes several scenarios and suited solutions possible.

“When you go away for a long time, there is the problem of humidity, which will lead to condensation on the walls. The lack of air circulation will further lead to a sewage smell in the house. What you need is a consistent temperature, and air circulation to erase the humidity.

“In an open apartment or villa the solution can be in switching on one air conditioner upstairs. The cold air will zinc down and the hot air will move upwards. If you leave all the doors open [inside the house], the air will circulate through the house.

In a narrower residence, this solution might not be suitable, and more ACs may have to be switched on to ensure air circulation in all parts of the house, Colin adds.

When deciding to leave the AC on, setting the right temperature is a step that can be taken to save what can be saved in energy consumption.

“The AC does two things; it cools the air and it removes humidity. It is the last function that we need when nobody is in the house,” comments Stephane. “When nobody is there, nobody will care for the right temperature, and to save energy this can be set a higher temperature than usual.”

“A temperature of 25-26 degrees would be suitable in these circumstances,” added Colin.

However, leaving the AC switched on carries risks too. “Leaving the AC on for a long period of time can lead to a blocked waste pipe. This can create damage much more regrettable than that of humidity.

“Somebody should be able to access your house while you are away. If this is not an option, I recommend switching the AC off,” said Colin.

Going to work

A different situation arises when the house is left for a shorter period of time, such as on a workday. In this situation the AC does not need to be switched on, thinks Colin.

“Here, the energy wastage outweighs the benefits of the cooling. The property is not likely to get very hot within the timeframe of a working day when the AC is switched on in the evenings. During that time, the walls will be cooled, and will maintain some of that temperature during the day.”

However, this will only be true if the air conditioner is functioning at its full capacity, and it is capable of cooling the air of the whole area, he adds.

“If your central or room air conditioner is more than 10 years old, it could be doubling your cooling costs,” warns the Dubai Electricity and Water Authority (Dewa). “Clean or replace your air conditioner filter monthly so your air conditioner runs efficiently.”

Further, drapes, shades, awnings and reflective materials can be useful to reduce the heat entering through glass, so can weather stripping and caulking around all doors and windows to keep the chilled air inside your house, tips Dewa.

Using the switch button too often

Do I waste energy whenever I switch the AC on and off? Some people fear that switching off the AC is the trigger to the high electricity bill, as it takes the AC a lot more energy to cool down the temperature from scratch.

True, energy consumption is higher when the room is hot and the AC has been switched off, says Stephane. However, it is not sure whether more or less energy is used when the AC remains on for a day long, as this depends on the size of the property, strength of the AC etc., he argues.

“One could try that out by going one way for one month, and the other way in the second month, comparing the bills of both months.”

According to Colin, there is not often a justification for the 24/7 air conditioning. “The energy used to cool a space all day is mostly more than what is used to cool a heated room. It usually takes about 35-40 minutes, and the house should be cool,” he concluded.

(Home page image courtesy Shutterstock)

Follow Emirates 24|7 on Google News.