Do's and Dont's of operating an Aircon


Do not overcool the room

  • Excessive cooling is a waste of electricity and bad for health.

Avoid high heat load in the room

  • Prevent direct sunlight into the room by using curtains, awning, sun shade, etc.
  • Do not open windows or doors for a long time while the unit is running.

Do not block the outdoor unit

  • When there is no air circulation, heat cannot be discharged, thus resulting in short circuiting.

Do not install your air-conditioner's piping exceeding the recommended length

  • Cooling capacity is reduced when your piping exceeds the recommended length.
  • The compressor would fail too as a result of overwork and insufficient oil return.
  • Warranty may be forfeited.

Do not pull out the power cord when the power is on

  • Serious electrical shocks may occur and cause fire.

Do not attempt to replace blown fuse with a metal wire or the like

  • Always use properly sized fuse to prevent fire outbreak.

Do not put heating apparatus too close to the air-conditioner

  • It will also increase the room's heat load, causing insufficient cooling.
  • The plastic panel may be deformed due to excessive heat.


Service and maintain your air-conditioner regularly
* Clean the air filter of the indoor unit regularly

  • Clogged filter may freeze up the coil, reduce airflow and cooling capacity.
  • Clean the filter once every two weeks, with vacuum cleaner, or by tapping lightly and washing in lukewarm water (below 40° C) with neutral soap.
    * Check indoor fan for unusual noises.
    * Clean indoor/outdoor coil.
  • Remove any dirt that may clog between the fins at least once a month.
    * Engage contractor for preventive service
  • At least once every two years, check the gas pressure, wiring connection and running current.
  • Clean the blower fan and chemical cleaning for the coil, if necessary.

Set the thermostat between 22° C - 26° C for optimum comfort

Turn on the air-conditioner early

  • If you expect a hot day, it is better to turn on the air-conditioner early rather than wait until the room is hot. That way, it will be easier to cool the room

Keep the room temperature uniform

  • Adjust the vertical and horizontal vanes to ensure good coverage of airflow to the room and to distribute uniform temperature.

Install indoor unit at a position where airflow is evenly distributed.

Ensure that there is no irregularity on the power plug and socket

  • If the plug is loosely plugged or there is any damage to the electrical wire cord, danger of short circuiting is great.

Remove the power plug when the unit is not used for a long time

Place your outdoor unit at a shady place

  • This would ensure higher efficiency.
  • Also make sure there is no obstruction to the airflow coming out of the outdoor unit

Make sure your air-conditioner is protected with a starter

  • TNB regulation requires a starter to limit running current as well as to act as a default-off switch.
  • A starter will prevent fire hazards as a result from overloading and over current.


Often, the selection of an air-conditioner's size is a guessing game. To many, buying an oversized air-conditioner may seem to be the solution to ensure that coolness is achieved. Far from truth, an oversized air- conditioner's high initial cost, high electricity consumption and eventual discomfort due to poor selection would definitely spell disappointment at the end of the day. Here's a checklist to help you understand and select a suitable air-conditioner for your home.

A. How large the cooling capacity needed depend on :

  • The SIZE of the room
  • The PLAN and ORIENTATION of the room
    Different room plans and orientations require differing cooling capacity even with the same room size. For example, rooms facing east and west, require higher cooling than rooms facing north and south.
  • The PURPOSE of the room
    Rooms with differing purposes will exude different heat loads. The higher the heat load, the higher cooling capacity is needed. A room's heat load is influenced by many factors (see above drawing). How much heat is insulated also depends on the kinds of material used for the walls and ceilings.
  • The LOCATION of the indoor and outdoor unit
    Higher cooling capacity is required when the indoor and outdoor units are located in places with excessive heat exposure.
  • OCCUPANTS in the room
    The number of people as well as their activities in the room affect the heat load of the room.

B. What are the differences and features to consider when buying an air-conditioner?

  • Cooling capacity
    For 1 hp, coolling capacity ranges between 8,500 Btu/hr and 10,000 Btu/hr in different brands. The higher the Btu/hr, the higher the cooling capacity.

Electricity Consumption
For 1 hp, EER (Energy Efficiency Ratio) ranges between 8 and 12 in various brands. The higher the EER, the higher the efficiency.

  • Airflow
    For 1 hp, airflow varies from 210 cfm to 300 cfm. Higher airflow provides faster cooling as well as better air circulation.
  • Built-in or external starter
    Built-in starters are maintenance free and more accurate.
  • Remote control
    Whether it is wired or wireless.



Did you know that an oversized air-conditioner consumes more energy, works less efficiently and provides less comfort when a smaller unit will suffice? Most people don't know that. Neither are they aware that by installing proper insulation such as awnings, curtains, glass shading, etc, in an air-conditioned room, the room's heat load will decrease and their cooling comfort will increase.

To facilitate your understanding, TNB and YORK in collaboration with the Ministry of Energy, Communications & Multimedia, have complied a list of tips to help you use your air-conditioner in a safer and more efficient manner.


You are attracted by the advertisement and the hot weather is making you feel very uncomfortable. So you decided to buy an air conditioner. What now, you may ask. What do I have to know before I decide on which air conditioner to buy?

Time and again we found out from surveys that people do not buy something just because it is the cheapest model around town. As for the air conditioner case, the situation become a little more complicated by the fact that buying an air conditioner does require some knowledge.

First we have to know what is the required cooling capacity for the room. This, we have to consult the contractor or dealer. They can help to do some estimation as to what Btu/hr or Horsepower that you need. Some brands offer higher cooling capacity for the same Horsepower. Buying the proper capacity air conditioner will save you on operating costs and breakdown costs. High efficiency air conditioner is also available in the market. Select a unit with high energy efficiency ratio or EER. EER is the ratio of cooling capacity of the unit per input power. In another word, the higher the EER, the more efficient is the unit.

Compare the features of the units, like air swing, wireless remote control and some other more sophisticated feature like auto faults detection. Price, of course is of great concern. But often, it is not the price that we are paying, but the value that we can get out of it. Value added features like after sales service, availability of spare parts, warranty period and of course, aesthetics are also important, if not more important. In the long term, unit with high efficiency ratio will save on the electricity. Another important feature to look into is the safety of the unit's operation, such as in the case of built-in starter.

One other area that we have often overlooked is the installation of the air conditioner. Good workmanship will save you a lot of troubles and time. Some of the problems that may arise from poor workmanship are like water leaking, unit trip due to incorrect power connection, compressor breakdown, and gas leaking. All these faults will bear serious consequences and are very costly.

Besides providing faultless installation job, a good air conditioner installer will be able to advise you on the cooling load required, best position of the indoor and outdoor unit, and your service maintenance needs.

So, it is always good to find out more about the air conditioner unit as well as the contractor before you buy anything. Again, it is not the price that you pay, it is the value that you get for what you pay.


One of the most dominant questions in our mind when we want to purchase an air conditioner is, what is the right air conditioner to use? This question points not to what brand of air conditioner to buy, but rather what is the cooling capacity required. To understand the selection of air conditioner, we first have to know the definition of cooling capacity.

Cooling capacity for a room is basically the heat load in a room that we have to remove in order to achieve certain room temperature and humidity. For most design, this temperature is 24oC and 55 percent humidity. Heat load is measure in Btu per hour. 1 Btu per hour is equivalent to the heat energy required to increase 1 pound of water by 1oF.

A compressor with 1 horsepower capacity is able to remove approximately 9000 Btu/hr of heat. To make things easier, it is generally taken that 1 horsepower means 9000 Btu/hr cooling capacity, even though there are some brands which give you higher than that, some as high as 10,000 Btu/hr from a 1 horsepower compressor. The higher the Btu, the higher the cooling capacity.

Heat in a room comes from many sources. From outside, heat come through windows, roof, floor and walls. The more exposure to the heat source, the greater the heat load will be. Therefore, rooms facing east and west have higher heat load than rooms facing north and south. Even the material of the glass and bricks affect the heat gain.

Internally, the heat sources are the number of people and their activities, electrical appliances, lighting, heat stove and fresh air that flow into the room. Of course, the bigger the room is, the higher the cooling capacity is required.

It is not easy to estimate the actual heat load of a room without going through some tedious calculation. You are advised to consult air conditioner contractors before you decide on the equipment. Bring along the plan and measurement of your room and be specific what is the function of the room, is it a bedroom or a living room?

There is however, a rule of thumb that could give you a rough estimation of the required cooling capacity. This can be achieved by doing a simple calculation.

First, multiply the volume of your room in cubic feet with a factor of 6. Determine the number of person using the room and multiply with 500Btu/hr, as each person produces 500Btu/hr of heat for normal activity. Add these two together, and you get the estimated cooling capacity.

The calculation just now is for bedroom only. For other applications, the factor has to be changed. This rule of thumb calculation is just for estimation purposes. It is advised to reconfirm with your air conditioner contractors again before you place your order.


When you are not sure what is the right horsepower air conditioner for your use, do you just buy the bigger ones to ensure you have sufficient cooling?

It may sound strange to you, but that is what we have found out in many cases.

An oversized air conditioner means installing an air conditioner far exceeding the required cooling load. On the surface, it may look like a good idea, but looking deeper, it has other consequences that may spell disappointment for you.

First of all, an oversized unit runs for shorter periods of time than it should. At higher capacity, it is obvious that it could cool the room in a very short period of time, thus causing frequent start and stop of the compressor to maintain the desired temperature. That would lead to higher power consumption because the starting power consumption is 6 times higher than normal running condition. A properly sized unit will run on longer cycle and are more efficient.

Because of the frequency of the start and stop of the compressor, the room temperature will fluctuate and this will lead to discomfort.

On top of that, it always costs more to buy a bigger unit and don’t last as long. A compressor that is subject to on and off too frequently will have more wear and tear and as such will have shorter life span. A larger than required air conditioner will also incur higher installation costs with bigger refrigerant pipe as well as more expensive spare parts.

Of course, a bigger unit will also produce more noise, because of the higher air flow.

Therefore, it is important to install the correct horsepower air conditioner for your use. However, it is not easy to calculate the exact cooling required for a particular room without going through all the detailed designs. Nevertheless, for home usage, some simple heat load estimates are quite close.

The best is to consult your air conditioner dealer or contractor who is competent to advise you. There are a lot of air conditioner specialists who represent reputable manufacturers in the market. When you purchase your air conditioner unit, bring along the plan and the measurement of the room and be specific about its usage.


There have been a lot of arguments about starter nowadays. Some people tried their very best to hide it, some think it is not necessary, and yet some insist they should have one. Starter is not part of air conditioning system but yet it is a necessary device in any air conditioner installation.

Let's find out why it that so. There are 2 main functions that starters perform:

a. As a device to limit running current

b. As a default off switch

The first function is to protect against electrical overloading and overcurrent. Overloading may be caused by dirty coil, faulty wire, loose wiring connections, irregular power supply, etc. The thermal overload protector act as a device that will trip the unit should there be high current. This is to prevent fire hazards as well as to protect the compressor.

The second function is to protect the unit when there is disruption in power supply. Imagine all the air conditioners in your area start at the same time when power supply is resumed. The power pull will be tremendous, causing overloading and other power related problems. This is especially serious for air conditioner due to the power usage of compressor, where for split units, the starting current is 6 times the running current. Starter act to cut off supply to the unit, so that the air conditioner will not start automatically by itself.

TNB regulation stated clearly that a starter is required for air conditioners. Therefore it is illegal to bypass a starter. Up until Built-In starter, mechanical starters are used. However, in a mechanical starter, the setting of the overload protector is manually adjusted. The problem lies in settings that are not accurate or mis-adjusted. Air conditioners with different cooling capacity require different current setting. If this is not done properly, you may not get the right protection.

On the other hand, YORK Built-In starter settings are all pre-set in the factory, providing a safer environment. Most importantly, all starters must be approved by Jabatan Bekalan Elektrik Dan Gas, the regulatory body of electrical applications.


You may like to know that it costs 19 cent per hour to run a one horsepower air conditioner. In a fully air-conditioned house, energy consumed by air conditioners could be as high as 40% of total electricity used. Even though air conditioner is among the higher energy consumers in a household, there are many ways to keep it running efficiently and thus, give you more value for your money.

High electricity bills are normally caused by inefficient systems. Some of the main factors that caused an inefficient system are:

a. The air conditioner is not properly maintained. Dirty coils limit the air-flow as well as smaller face area for exchanging heat. This will reduce the cooling capacity and thus the air conditioner has to work harder and longer.

b. If you use an improper horsepower air conditioner for your room, a lot of energy will be wasted. Whether it is undersized or oversized, the compressor will find it difficult to maintain the pre-set temperature.

c. Some other faults like loose wiring connection, refrigerant piping exceeded the recommended length as well as blocked air discharge, are also contributing to high energy consumption.

Here are a few tips that would make your air conditioner work for you. Some of these tips are easy to apply but there are also some that require some adjustment to your air conditioner.

1. Set the thermostat between 22 to 26 degree Celsius for optimum running condition. Don’t overcool the room. If you do not feel the coolness, it is more likely that your air conditioner is undersized or the cool air could not reach you due to the position of the blower.

2. Saves on your energy usage by installing proper insulation. Glass shading, curtain, blinds, awning and special roof insulation are some of the permanent insulator that will save on the long run.

3. Do not block the air outlet of your outdoor unit. Keep good air circulation for efficient heat discharge and install your outdoor unit at the shady side.

4. Get the right horsepower of air conditioner for your use. An oversized or an undersized unit will run inefficiently.

5. Adjust the vertical and horizontal louvers for maximum air distribution.

6. Maintain your air conditioner regularly. Wash the air filter every two weeks. On top of that, engage a specialist to do preventive maintenance every two years. If the coil is too dirty, chemical clean may be needed.

Those are some of the keys to keep your air conditioner at optimum running condition. You will face less breakdown, longer life span, saves more and less inconveniences.