Q. What is cooling capacity?

It is the measure of the air conditioner’s ability to cool a room / space. A common measurement is “btu/hr”; there are other measurements, too. The higher the number, the better is the equipment in cooling. e.g. a 12,000 btu/hr air conditioner can cool better than a 9,000 btu/hr one.

Q. What is a System-2?

A System-2 consists of 1 no. outdoor unit with 2 nos. indoor units; hence, the system can cool 2 rooms. There are also the System-3 and System-4 for 3 and 4 rooms respectively

Q. How do I know what cooling capacity I will need for my room?

We can assess, calculate and advise you. We look into the size of the room, the number of people occupying the room, what heat sources are there (e.g. the wall exposed to the sun) and other factors involved.

Q.Someone said I needed a 1-h.p. in each of the 2 rooms. What’s that?

That is another measurement of cooling capacity. 1-h.p. is about 9,000 btu/hr

Q.What type of air conditioner should I get if I want to cool 2 bedrooms?

Normally, for residential use, wall-mounted units are used. Depending on the size of your rooms, you may choose between 2 nos. single-split air conditioners or a System-2. The capacity for each room will depend on their sizes and other factors for which we can advise.

Q.I live in a 5-room HDB apartment. Is it possible to air-condition all 4 rooms?

Yes, it is possible. Generally, a System-4 can be installed but may not cool sufficiently all 4 rooms at the same time. e.g. a 24,000 btu/hr System-4 theoretically can provide up to 6,000 btu/hr cooling per room simultaneously if all the indoor units have the same capacities. That 6,000 btu/hr is rather insufficient.

Of course, there are larger System-4 air conditioners with outdoor units rated at 32,000 btu/hr (theoretical 8,000 btu/hr for each indoor unit) or higher. However, such units require larger incoming power supply. HDB homes have low incoming power supply and these units cannot be installed in HDB apartments unless the power supply is upgraded, which may cost a significant sum to do so.

Inverter air conditioners can provide the solution.

Q.What is inverter air conditioner?

Prior to the advent of inverter air conditioners, the compressors of regular air conditioners were (and still are) powered by standard motors. These motors, and hence the compressors, are either “on” or “off” depending on cooling needs. However, they cannot be on-and-off too often as it may

  • Adversely affect the motor
  • Adversely affect the compressor
  • There is a current surge every time the motor starts (the starting ampere may be 30 ampere or more)

So, at a pre-set temperature in the room, the compressor will re-start and stop only at about +/- 2 or 3 deg. C of that pre-set temperature. Hence, one may feel “too-warm” or “too-cold” using a standard air conditioner.

In an inverter air conditioner, however, the inverter motor

  • Starts at very low amperage (say, 5 – 10 amp); this is called “soft-start”, which does not produce a current surge.
  • Can run at different speeds depending on how much refrigerant is required to be delivered to the indoor unit/s

The advantages of an inverter air conditioner are therefore

  • “soft-starting” allows, say, 2 nos. of System-2 to be installed in an HDB apartment to cool 4 rooms efficiently without electrical up-grading
  • A more comfortable ambience can be achieved as the controls provide the required refrigerant according to the pre-set versus the room temperatures. The ambient temperature is about +/- 1 deg. C from the pre-set.
Q.Is inverter air conditioner energy-saving?

No! You pay for whatever cooling you use. If there are savings, they are
Negligible. Note that the inverter motor and its compressor almost never stops running except occasionally when the outdoor temperature is low during a very cool day.

Customers buy inverter air conditioners primarily for the advantages listed in the above tab “What is inverter air conditioner?”

Q.What is the best aircon brand?

That is a tough question to answer! Different brands have different equipment models with different strengths. You should discuss with your dealer on your needs and look for equipment that
– can meet your needs
– has proven reliability
– is supported by reliable after-sales service
– offers you sufficient warrantees (e.g. 1-year on equipment and 5-year on compressor)

Generally, Japanese brands have a higher reliability rating and good equipment ranges. More importantly, the dealer installing for you must be competent and reliable.

Q.How do I know if a dealer is reliable and competent?

The law of business applies. Good dealers stay in the business while bad ones come and go.

Look out for
– How long has the dealer been in the air conditioning business?
– Does it have repeat customers? Repeat customers are a powerful testimony of customer satisfaction.
– What after-sales service does it provide?

Q.How often do I need my air conditioner to be serviced?

As with all equipment, servicing is important so that optimum performance can be obtained all the time. It is unwise to skip servicing and call your repairman only when troubles have arisen because it can be more expensive and may take more time (deprive you of the equipment use for a few days). Servicing is a pre-emptive measure which keeps your air conditioner in good condition all the time.

The suggested servicing schedule is
– general cleaning of filter, drain pan, drain pipe and outdoor unit (including gas check) quarterly
– annual chemical cleaning

Very cheap servicing packages are available in the market but be wary about unbelievably low prices! Maintaining an air conditioner system is not about using a feather duster and a 10-minute job!