Wednesday, January 6, 2010

Basic Considerations

Inverters or Non-Inverters?

Some sales people will tell you that aircons using non-inverter technology are more reliable and/or cheaper to maintain and repair than inverter aircons. Or that R22-based aircons cost less to maintain because the R22 refrigerant is cheaper to refill than the new R410A refrigerant.

Don't believe them.

Inverter technology today is highly advanced and compressors with inverter operate more efficiently and at lower energy costs. Rather than repeat what the experts are saying, I'll give you the links so you can learn why you should buy aircons using inverter technology:




R22-based or R410A-based Aircons?

This is a no-brainer: go for the newer R410A-based aircons. Why? Simply because whether you like it or not, R22-based aircons are being phased out! The dealers know that, and whether they admit it or not, they have to unload R22-based aircons on unsuspecting and ignorant consumers, otherwise they will incur huge losses on unsold old stocks. So they tell you half-truths like "...oh, the R410A types are more expensive to refill... R410A-aircon costs more to repair.. etc, etc..."

Sure, they may be more expensive to refill initially, but as times goes on with the phasing out of R22-based aircons by 2015, it will be prohibitively expensive (or even impossible) to get R22 liquid refrigerant for your R22-based air cons!

So don't be conned!

Cooling Capacity

OK, once you have decided what type of air-con you want to install, you need to know what sort of cooling capacity is required to cool down your space, be it the bedroom, dining, study or living room, etc.

Some dealers have their own formulas. Obviously the volume of the space, rather than simply the area, and outside ambient temperature, play a part in determining the cooling capacity required, but the following rule of thumb seems to work for me:

Area (Length x Width) X 65 = BTU/hr

E.g. Room size 10ft X 10ft = 100ft2 X 65 = 6,500BTU/hr.

Placement of Fancoil and Compressor

Usually the location for the compressor is pre-determined for you if you live in a HDB flat. If not, the following energy-saving tips may help you decide on the placement of the compressor:

NEA Website

In my case, my flat was built in the 1980s when an aircon ledge was not provided for in the basic design of the apartment, and so I had to decide where to place the compressor. I could place the compressor outside the MBR, for which HDB had provided a cut-out hole in the wall. However, I decided to site the compressor below the window in the dining room. That way we would not be disturbed by the sound of the compressor operating in the night outside the bedroom window. Moreover, the dining room location was less exposed to direct sunlight and more "centrally" located to all the fancoil units. This resulted in a shorter trunking (read: less heat loss, more effective cooling) between the fancoils and the compressor.

Some have advocated placing the fancoil so that the cool air does not blow directly on the occupant(s). This is bad advice! Very bad advice indeed. You know what? I site the fancoil so that the cold air blows directly onto the occupants who wanted cooling!

The purpose of installing an aircon is to cool down the room quickly and effectively, and then to maintain the room at an optimum and comfortable level i.e. neither too hot nor too cold. If the air con doesn't blow directly at the space you want to cool, but instead blows the cold air somewhere else, it will take a longer time before the room becomes comfortably cold enough for you.

In the past, aircons did not have vanes that automatically direct the airflow around the room, so that once the room has cooled down, cold spots would develop as the aircon continued to blow directly at the same spot in the room.

Or even where the vane swung from side-to-side, the occupants would feel frigid and uncomfortable when the cold air continued to blow on them after the room has become cold. This was because there was no mechanism to reduce the airflow automatically and to reset the room temperature automatically once the room has cooled down.

Today, however, air cons are designed with a host of new innovations: not only do aircons have vanes that swing left and right, they also rotate up and down. And some are linked to fan motor speeds: to "push" out a higher or lower volume of cold air as the occasion warrants it.

I mounted my Starmex, for instance, directly above the headboard in the MBR. Now, with this placement, if I feel uncomfortably hot as I go to bed, I could turn on the aircon, and it will immediately shoot out a direct blast (because I had set it so) of cold air to cool me down fast as I lie on the bed. Refreshing!

Few minutes later, after my body has cooled down, I will set the remote control to "I Feel.." auto operation mode. That automatically sets the aircon to produce the optimum room condition for sleep with a one-touch operation. And I could not hear any motor sound from the fancoil, only feel the cool air. Amazing!

Energy Efficiency

Of all the major appliances in the home, aircons and refrigerators consume the most energy in the monthly electricity bill. Half to two-thirds of the energy consumption of a typical household in Singapore goes to operating air-conditioners and refrigerators, hence households are urged to choose energy efficient appliances when buying such goods. According to the National Environment Agency, a household choosing a 3-tick rather than a 1-tick air-conditioner can save about $500 annually through reduced electricity consumption.
The Tick Rating is defined by the NEA as follows:


Type Minimum COP 100%1 (W / W)
No. of Ticks 0 1 2 3 4
Casement, window, single-split (non-inverter) <> > 2.5 > 2.78 > 3.2 N/A
Multi-split (non-inverter) <> > 2.64 > 2.92 > 3.34 N/A
Split type (inverter)2
•Weighted COP 3
N/A<> N/A> 2.64 N/A
> 2.92 > 3.06
> 3.34 > 3.34
> 3.76
1 COP 100% is defined as the ratio of total cooling capacity to effective power input at full load cooling capacity
2 For split (inverter) type air-conditioners, the model shall meet both the minimum COP 100% and weighted COP3 Weighted COP = 0.4 x COP 100% + 0.6 x COP 50%


Ever wondered why there is condensation on aircon trunking inside the home?

If the insulation material used to cover the copper pipe is not effective or thick enough, water will condense around the plastic trunking in the home as the climate here is very humid and hot all-year-round.

The dealer knows about the condensation problem. But instead of doing a proper aircon installation, some dealers use inferior or inadequate insulation foam knowing the consumer will experience the condensation problem subsequently.

This is outrageous!

Every consumer, I believe, has the right to expect an air con to be installed correctly and properly to meet local environmental and climactic conditions. And that includes proper insulation so that water condensation problems do not occur on the trunking. If a dealer uses substandard materials during installation, and there is water condensation on the trunking, the dealer should rectify and correct the installation.

Far from it -- instead of admitting responsibility, the dealer is quick to lay the blame on the consumer. The dealer will brazenly tell the consumer that because he did not agree to pay for thicker insulation material, inferior insulation material was used, resulting in condensation on the trunking!!

And so, in the absence of strong consumer protection laws here, consumers have no choice but to timidly pay up to the dealer blackmail.

What will dealers think of next to inflate profits? Extended warranty? Thicker copper piping? Leakage prevention?

So like everyone else, I paid up meekly for 1/2-inch Armaflex insulation foam because I know full well the consequences of not having the proper insulation foam for my aircon trunking. But not before I checked that I got what I paid good money for.

Indeed, I found that Armaflex is the registered trademark of Armacell, the world's leading producer of insulation foam. Armacell is the global market leader in foams technology. The company invented Armaflex®, the world's best known and most trusted trademark in elastomeric foam insulation. With more than 50 years of experience in foams, Armacell manufactures foams and expanded rubber products for automotive, industrial, sports, leisure and packaging industries -- in addition to mechanical insulation.

Class '1' Armaflex (Fire Performance, BS 476 Part 7 1997) is a dust free, fiber free CFC & HCFC free (ozone depletion potential of zero), flexible, black, closed cell, elastomeric nitrile rubber insulation providing a highly efficient method of controlling condensation and insulating against both heat loss and heat gain.


Before you call in the aircon installers, you should study your apartment interior to decide where and how you want to run the trunking. This is important particularly for those living in flats where the trunking is exposed and not concealed behind a partition board or wall.

To minimize the risk of water flowing back into the fancoil unit and dripping onto the floor, I generally prefer to run the trunking along the bottom near the floor line. You should also check that the installer uses a water or spirit level to ensure the proper gradient of the piping so that water flows properly to the drainage outlet in the bathroom.

To minimize heat gain, the fancoil units, where it is practical to do so, should be sited as near as possible to the compressor.

Finally, place the fancoil so that the blower fan blows directly into the area you wish to cool. A central location along the wall near the ceiling is preferred to a corner location in this respect.

Electrical Issues

Older flats built by the HDB have a limitation on the amperage of the aircons that can be installed. My flat has such a limitation, and the aircon load is limited to a maximum of 8.5 amperes only.

However, the dealer told me it is unlikely for multi-split units to hit the ceiling on current usage and asked if I was prepared to authorize him to set the compressor maximum current load to 11 amperes. Obviously I agreed because that would give me higher cooling capacity when the occasion demands for it.

Obviously you would need to run the electrical wiring for your apartment before the installer comes to fix up the aircon. Without any source of electricity he would be unable to test the aircon for correct and proper operation after the installation.

Finally, you should locate the 15-amp socket for the compressor anywhere, as long as the socket is near the aircon trunking, so that the cable could run and be hidden inside the trunking itself. Thus I have the 15-amp socket located inside the MBR, although the compressor is placed outside the window of the dining room.

Quality Materials Used

As the materials used will be concealed inside the trunking, check the materials for quality and specifications, such as 1/2-inchClass 1 Armaflex insulator foam, before installation commences. Armaflex is a registered trademark of Armacell, the world's largest and foremost insulation manufacturer.

Starmex multi-split inverter aircon rated 4-Stars for energy usage by Spring Singapore / NEA

Getting down to work

Trunking for Pipes

Drainage pipe : Don't let the installer decide without seeking your direction on where and how to run the drainage discharge pipe. You let them be, and they will simply install wherever and whichever is most convenient for them. In my case, I specifically directed them to install the drainage pipe so that the water is discharged as near as possible to the bathroom drainage hole. What they had wanted to do was to run the drainage pipe to the near end, instead of the far end, of the bathroom. The near end meant less work for the installer, and the water would flow across the bathroom floor to the far end where the bathroom hole was located.

Drainage Pipe

The installer used a blow-torch to soften the plastic pipe (which was pointing upwards!) and bent it downwards so that water will flow smoothly out to the drainage hole.

You don't need to locate the 15-amp socket near the compressor but you need to locate the 15-amp socket along the trunking so that the electrical wire could be concealed in the trunking.

Bedroom: MSXY-GA10VA Starmex 9,000 BTU Inverter R410A Fancoil Unit

Living / Dining Room: MSXY-GA26VA Starmex 26,000 BTU Inverter R410A Fancoil Unit

Posted by GreenCoal at Tuesday, April 15, 2008

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