Air Conditioning — Commonly Asked Questions

In this FAQ, we attempt to answer all sorts of frequently asked questions (FAQs) from customers in Singapore, ranging from what air con professionals provide, to the details of chemical flushing and whether you should do it yourself.

Table of Contents

General questions

What do air conditioning professionals provide?

Different air conditioner service providers offer different services. As different brands of air conditioner may require different know-how to repair/service, it is important to clarify their services before engaging them.

The most common types of services are:

  1. Regular contract servicing/maintenance
  2. Air conditioner installation works
  3. Air conditioner repairs
  4. Chemical overhaul
  5. Chemical cleaning / Chemical flushing/ chemical wash
  6. Evaluate and advice
  7. Aircon installation
  8. Diagnostic and inspection
  9. Gas top ups and inspections
  10. Troubleshooting

Why is the room not cold enough?

The main reasons why the room isn’t cold are as follow:

  1. The filter is dirty
  2. Temperate settings of air conditioner is too high
  3. Area capacity for air conditioner cooling is too large (i.e. not enough aircon units to cool the entire)/ the air conditioner installed is under-sized
  4. Thermostat is faulty
  5. Not enough compressor gas
  6. Refrigerant leakage
  7. Components of aircon may be faulty
  8. The indoor fancoil is dirty resulting in weak dissipation of cool air.
  9. The outdoor condenser is dirty resulting in incapable of producing cooling refrigerant.
  10. There may not be enough refrigerant in the air conditioning system.
  11. There might be some problem with the air conditioning system resulting in non-continuous operation of he system.
  12. Check if the door and windows are shut.

Regular aircon servicing in Singapore of at least once per year is advised to maintain the working conditions of the air conditioners.

Why is the aircon leaking water?

The main reasons for this:

  1. Clogged drainage pipe: Normally, the air conditioner’s water will condensate inside the fancoil. This will usually be released in the drainage pipe. If the drainage pipe is clogged or choked then water will start leaking. General aircon servicing normally involves the vacuuming of the drain pipe which may rectify the choked pipe problem.
  2. Wear and tear of the air conditioner
  3. Poor installation of air conditioner
  4. The gradient of the piping between the fan coil and drainage is too gentle causing leakage

Why is that water dripping from the outdoor condenser / compressor?

This is normal as condensation happens when condenser cools the surrounding warmer air.

Why does the aircon produce a foul smell?

There may be several reasons for this:

  1. Surrounding smell may be absorbed into the unit. Example could be small from furniture, cigerattes, food.
  2. Bacteria formed by microbes in the warm dark humid environment in the indoor fancoil unit may be causing the smell. Sometimes when the smell is very bad you may need a more intensive chemical treatment to rectify this problem.
  3. Pollutants like smoke from cigeratte or haze could be absorbed by the unit. The solution to this is intense chemical treatment of the air conditioner.

Why is my air conditioner noisy?

There cold be several reasons:

  1. Vibration noise resulted from dirty indoor fancoil/ outdoor condenser.
  2. Noisy draft resulted from dirty indoor fancoil
  3. Some components in the air conditioning system may be mounted loosely
  4. Faulty parts in the air conditioning system.

Why is the aircon not working?

One common reason is that the electrical power is not being supplied to the air conditioner. It could be loose wiring or that the electrical panel is malfunctioning. A qualified professional should be engaged if it is more complicated than a simple repair.

When do I need a gas top up and or inspection?

Gas top ups is necessary in the case of unsealed leakage. Before topping up the gas, it is essential to seal the leaking areas. Once it is done, you do not need gas top up until there is a leakage issue again. A number of factors may lead to gas leakage.

These may include improper installation, poor quality copper pipe and more. We recommend you to ask an air con professional before attempting any gas top up on your own.

How often should I service my air-con?

The basic maintenance that is recommended is the cleaning of the air filter and outer panel of the air conditioner every 2 weeks. This will helps to improve the air conditioning of the room.

For a more in-depth servicing, it is recommended to service 3-4 times a year for residential properties, and once a month for commercial.Please seek the assessment of a qualified technician.

What does regular contract servicing/maintenance includes?

Regular contract servicing/maintenance. Includes:

  1. Cleaning & checking air filter, front panel & cover
  2. Checking purifying filter
  3. Cleaning & checking indoor evaporator coil
  4. Cleaning & checking indoor drainage tray
  5. Vacuuming of drainage system
  6. Checking fan bearing and lubrication (if necessary)
  7. Checking compressor suction and discharge pressure

What benefits should I expect if I services my air con unit? What happen if I do not do any aircon servicing?

The benefits are as follow:

  1. Improved efficiency:Regular air conditioner servicing help improve the efficiency of the air conditioner unit. This saves electricity and cost over time (with lesser repairs needed and it working longer). The electrical consumption of the air conditioning equipment will be lower.
  2. Cooler rooms:Air conditioner units that are regularly maintained perform at their optimum capability leading to a cooler room.
  3. Lesser repairs and longer lifespan of air conditioner: If you don’t maintain your air conditioner regularly, like all products it will not last as long as it possibly can. Problems such as leakages will be minimized.

We strongly advice you to get the air con unit regularly serviced. Find more reviewed and rated professionals from our platform.

Can I DIY the general aircon services myself?

Whilst you can do simple maintenance work such as washing filters and cleaning the fancoil cover yourself, it is best to contact your air conditioner servicing provider so as to ensure your air conditioners are thoroughly serviced and checked.

Why does the air con needs chemical cleaning / chemical washing?

When an air conditioner is badly clogged or choked and a general service can’t improve the condition, an overhaul is necessary.

Chemical cleaning is a more thorough process in servicing an air conditioner unit. It is advisable for those units which are badly clogged. In an overhaul, the air conditioner is dismantled part by part and chemically wash.

What does chemical flushing and overhaul include?

Chemical overhaul, includes:

  1. Lubricates fan bearings to ensure the unit operates quietly without producing any noise
  2. Checks thermostats and controls of the unit
  3. Cleans pipes, blower wheel and drain pans with appropriate chemicals
  4. Cleans fan evaporator coil to facilitate smooth transfer of heat without the build up of dust and grime
  5. Replaces faulty bearings and eliminates operational noise

Can I do my own chemical flushing?

It is not advisable to do your own chemical flushing — if not done properly, many other problems may occur.

Why must the fancoil unit be dismantle for chemical cleaning / chemical washing?

By dismantling the fan coil unit, the air conditioning individual components can be washed thoroughly, as compared to justinserting a water tray to wash away the chemical.

This will help better clean the unit and also not leaving behind chemical residue that may leas to the corrosion of the fan coil.

How should I know if my unit is set to its optimal temperature?

An air conditioner’s optimum temperature is 25-26 degrees. If you set at 1 degree higher, this could lead to an increase of operating cost at up to 15%.

Why does ice forms on the copper pipes of the condenser (outdoor)?

Ice forms for 2 primary reasons:

Ice forms on the copper pipes of the condenser if:

  • The gas in the system is insufficient
  • Ice-formation on the suction pipe could be caused by a dirty fancoil unit or, a dirty filter or, the indoor unit blower is not rotating..

What should be done if there is a air conditioner refrigerant gas leaking problem?

A trained technician should perform pressure testing to trace and repair the leakage point. Upon completion of leaking repair, a correct amount of refrigerant gas should be top up.

What is the advantage of Air Purifying Filter and how often do we have to replace it?

Air purifying filters can remove smoking odour, human smell, impurities and harmful particles in the air condition space. Most new model of air conditioner comes with air purifying filter. Leaving dirty air purifying filter in the air conditioning system will affect its cooling performance.

Its recommended that the purifying filter is replaced every three to six months.

Why should I sign an aircon service maintenance contract?

Having a regular service maintenance importantly ensures you have a healthy living environment. The second benefit is that it usually prolongs the lifespan of your aircon. Lastly, having a regular maintenance allows you to buy packages at a discount which could save you more money overtime.

What should I look out for when buying an air conditioner unit?

There are 4 areas of consideration to choose an aircon and aircon services in in Singapore:

  1. Areas required for air conditioning.
  2. Cooling space and power required.
  3. Determine the brand and type of aircon you desire, such as aircon servicing efficiency.
  4. Budget for an air conditioner.

Which air conditioner brands are better?

There are many brands of aircon in Singapore and each brand has their own flagship models (with different strong attributes).

Talk to our air conditioner professionals in Singaporeand ask them for their opinions regarding your air conditioner installation.

What is the average lifespan of a residential air conditioner?

With professional aircon servicing and installation, an aircon can last about 6-7 years.

What is the warranty period of aircon units?

In market, the norm is that for residential units, warranty period for the spare part is 1 year and for compressor is 5 years, depending on the supplier/contractor.

What is the difference between a window unit and a split system?

A window unitis a single unit that is installing in any wall or window opening. All the components required for the aircon to function is packaged in it, and no piping in required for its installation.

A split unitconsists of an outdoor (external) compressor unit and an indoor (internal) fan coil. The fan coil unit (FCU) helps to cool the room while the external compressor cools the surrounding air and provides it to the FCU. Hence, piping is required for installation.

A multi-spilt unit consists of an outdoor compressor and more than 1 FCU. It enables cooling of multiple rooms simultaneously.

For performance wise, there are two main key differences between a window unit and a split/multi-spilt unit are:

  1. Window units generally requiresmore electricity to operate, hence are generally incur a higher monthly electrical bill.
  2. Because of the way a window unit is designed, it generates more noise during operation.

What does an inverter air conditioner means?

An inverter aircon consists of an inverter circuit which helps to balance and regulate the workload of the compressor. At such, the compressor will work more efficiency and helps to reduce on the electrical bills.

How do I determine the power capacity required?

Generally, use the simple equation below to calculate the amount of power required for a room/space:

Area (length x breath) x 65 = BTU/hr

Example: Room (10 ft x 10 ft) x 65 = 6500BTU/hr

Take the BTU/hr and multiple it with 0.000293 to convert it to KWh (energy unit used in Singapore utility system)

This means that in 1 hour, aircon will require 6500BTU of energy which is about 1.9KWh (6500 x 0.000293) of energy.

Why is the air con switches OFF by itself and the aircon indicator light is blinking / flashing ?

The blinking / flashing of indicator light usually indicates that there is a fault with the air conditioning system. Hence the air conditioner switches off by itself. It is a protective function to prevent the air conditioner from further damage.

A qualified air con technicianis needed to diagnose and repair the indicator light problem.

Why does the air con switches ON and OFF by itself ?

This usually happens when there is a fault with the indoor electronic circuit board. The circuit board controls the operation of the indoor fan coil and damage causes it to lose its operational control. A repair or replacement of the circuit board is necessary.

Why the air conditioner cannot be switch ON using the remote control ?

The fault might lies in the remote controller or the indoor printed circuit board. Try the remote controller on other fancoil and if it works, your remote controller is fine. If the fault lies in the printed circuit board, you need to engage a qualified technicianto do repair on the printed circuit board.

Why is the fan coil unit still operating when the condenser is not?

The fan coil unit and condenser operate independently. The fan coil transfer the cooled air from the condenser to your room while the condenser cools the air. Hence, even if the condenser is faulty, the fan coil will since transfer the air for the condenser to the room.

Do we need to service the condenser (outdoors) ? If, yes, how often?

It is recommended to service the condenser (outdoor air conditioning unit) at least once a year to make sure the air circulation of the unit is not blocked. Having a blocked condenser will affect the cooling efficiency, a shorter compressor life and higher electrical consumption.

Sometimes, it is subjected to environmental condition, which requires a qualified aircon technicians to give recommendations.

What is pressure testing of air conditioning system and why it is needed?

When the refrigerant gas in an air conditioning system depletes away and the air conditioner needs to regularly top up refrigerant gas, we can suspect that there is air conditioning refrigerant leaking in the system.

Pressure testing work will help to identify which is the leakage area. Normally high pressure is induced into the condenser, fancoil and refrigerant piping to identify where is the leakage. Further repair work will be quoted upon identifying the leakage area.

Note: Pressure testing work is a testing process (not repair work) to identify the leakage area. This work will not be able to rectify the fault but it’s a necessary process to define the scope of repair deriving from the result of the testing work. The leakage area defined herein is an indicative section of the refrigerant system.


Job specific questions

What types of aircon services do you provide?

Different air conditioner service providers offer different services. As different brands of air conditioner may require different know-how to repair/service, it is important to clarify their services before engaging them.

The most common types of services are:

  1. Air conditioner installation
  2. Repair and maintenance
  3. Chemical flushing
  4. Chemical overhaul
  5. Evaluate and advice
  6. Aircon installation
  7. Diagnostic and inspection
  8. Free gas top up and inspection
  9. Troubleshooting

The different types and brands of air conditioner include:

  1. Window air conditioner
  2. Casement air conditioner
  3. Residential split air conditioner
  4. Commercial air conditioner (Daikin VRV system)

What should I look for when engaging an air con professional/contractor?

When engaging an air conditioning company (air conditioning contractor), you should go for a company that is established and reliable. Find out their profile and experience and their after-service warranty

Does the professional provide warranty for the service?

We also provide 30 days of post service warranty for all jobs rendered. Usually air conditioners have warranty for one year and its compressor for five years. Please clarify this with the professional whom you have engaged.

How long does the air conditioner installation take?

Typically takes between 4-6 hours depending on the scale of installation.


This post is subjected to disclaimer.

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SGHomeNeeds’ vision is to provide comprehensive, unaltered and honest feedback about all home service providers in Singapore. Our platform aims to empower homeowners to select the home service providers which can best suit their needs.

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