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Working from home with the air-con always on? Tips to take the heat off your electricity bill

Plus, why do you need a chemical wash and how often should you get your air-conditioner serviced? Read the answers in this installation of the Household Hacks series.

Our location in the armpit of the equator means it takes a lot to stay sweat-free in Singapore. A lot of energy, that is.

Take our reliance on air conditioners at home, for instance. Air-conditioning accounts for up to a quarter of an average Singaporean household’s electricity consumption, according to this article. Furthermore, about 99 per cent of condominiums have air-conditioning installed.

But no one's in a hurry to switch off the air-conditioner yet, especially when many of us still work from home. So, what can we do then to help shave dollars off the electricity bill?

Set the temperature at 25 degrees Celsius or higher, said Dr Lieu Chee Fui, the programme chair of Republic Polytechnic’s Green Building Energy Management diploma course. For every degree raised, you can save about S$15 a year, he said, citing National Environment Agency guidelines

“In recent green building designs or net zero energy building designs, it is also proven that a temperature of 27 degrees Celsius, together with the use of a ceiling or standing fan, can reduce the bill while providing the same level of thermal comfort,” said Dr Lieu.

(Photo: iStock)


Getting your units regularly cleaned helps a lot as well. All the dirt and dust that accumulate in the air vents and filter can impede the cool air’s flow and cause the air-conditioner to use more energy to reach the set temperature, according to the Energy Efficient Singapore website

You can clean the filter yourself every two to three weeks if you’re a heavy user (that is, your air-conditioner is switched on day and night daily), said Dr Lieu. Clean the filter more frequently if your room is dusty, he said. “Just make sure that the filters are properly cleaned and dried before putting them back into the air-conditioners.”

In the meantime, arrange for professional servicing twice a year, if you only switch on your air-conditioner at night, said Dr Lieu. “If you are a heavy user, opt for servicing three or four times a year,” he said.

Servicing will typically involve “cleaning the air filter (and other filters, depending on the model), indoor fan coil unit; vacuuming the drainpipe; and checking the compressor motor's lubrication, compressor suction, discharge pressure and refrigerant level", he explained.

(Photo: iStock/Yurich84)

With all that regular cleaning, do you still need to get a chemical wash? Yes, you do. “The chemical agent or solution will help to remove the dirt or dust stuck to the surfaces of the internal parts such as the evaporator coils, which are difficult to clean ourselves,” said Dr Lieu.

You can opt for a chemical wash annually but if you only use your air-conditioner at night, you could wait for two years, he said.

Regular servicing is key to keeping your home nice and cool because if you don’t keep up with the servicing, you might run into the following situations. 

SCENARIO 1: The air-conditioner is blowing out air but it is not cold

According to Dr Lieu, this could be due to the depleted refrigerant. This coolant undergoes evaporation over and over again to produce the cool air that your air-conditioner emits.

Regular servicing would pick up the depleted refrigerant level, he said. The refrigerant can be topped up where necessary to solve the issue.

(Photo: iStock/justocker)

SCENARIO 2: The air-conditioner is suddenly leaking water

This is generally due to a clogged drainpipe, said Dr Lieu. “Over time, dust or mould can build up near the drainpipe and form a sticky jelly. If the air-conditioners are heavily used and are not serviced for a long time, the slimy jelly might eventually clog the drainpipe, causing the condensed water to flow out from the air-conditioners.”

The burning of essential oils or using an air purifier with an essential oil with the air-conditioner switched on may also promote the formation of the slimy jelly, said Dr Lieu, citing some studies.

“If your air-conditioner has such an issue, you can use a brush or cloth to clean the water tray regularly,” he suggested.

(Photo: iStock/Vacharapong Wongsalab)

SCENARIO 3: The air-conditioner creates rattling or squeaky noises when it’s working

Such noise might indicate that the air-conditioner is starting to deteriorate, said Dr Lieu. “Some of its internal parts, such as the motor of the compressor or fan might be loose."

Regular servicing would include checking the state of the fan, compressor motor's lubricant and/or compressor suction and discharge pressure to detect any loose or moving parts, he said.

“It’s good to conduct a quick check for loose screws or bolts, and tighten them if necessary.”

SCENARIO 4: The condenser unit heats up very quickly and it gets very hot

The condenser unit is the box that sits outside your apartment. If it heats up quickly, it is likely that the fan that cools it down is not working properly, said Dr Lieu.

“The malfunction of the fan could be due to wear and tear, which is unavoidable. But as the condenser unit is usually located outside on a ledge, it is not advisable to fix it yourself,” he said.

(Photo: iStock/UJ Alexander)

SCENARIO 5: There is a foul smell coming from the air-conditioner when it’s blowing out cool air

That odour could be a sign of mould or fungal growth, said Dr Lieu, that is caused by the high humidity level in the room. The moisture could have come from the air-conditioner or the moist air in the room wasn’t allowed to ventilate.

“You can use the dry mode (look for the water droplet symbol) occasionally and the air-conditioner will act as a dehumidifier to help remove the moisture,” he suggested. “Other than that, clean out the water tray during servicing to prevent dust or mould from building.”

SCENARIO 6: The air-conditioner doesn’t work when you activate the controller

Check that the batteries in the remote controller are not low on power. Perhaps the air-conditioner “is not able to receive the signal from the remote controller from your location”, said Dr Lieu. “Move a little and point your remote controller towards the air-conditioner; it should work.”

If it’s not a remote controller problem, check your home's circuit breaker box for any tripped switches and flip them back on, he said. “If you are unfamiliar with electrical work, please seek professional advice from air-conditioner servicing companies.”

Source: CNA/bk