Monday, September 14, 2015

Midea multi-split air conditioning

When I moved to my new place, it already has a system 4 air conditioning. Although working, it is an old non-inverter system and hence electrical consumption is pretty high.

With the haze greeting us again this year, the aircon is used more. And judging by recent days, it looks like it may get even worse and so will my pocket.

While looking for a replacement, I came across this offer from Gain City for the Midea system 3 for $1799 which consists of

Indoor unit - 3 x Oasis 9K BTU MS11MI-09
Outdoor unit - 21K BTU M3OA-21CDN1-QC4 (2 ticks from NEA)



It comes with a 2/5/6 years warranty (for parts/installation/compressor respectively) with the option to extend the warranty for parts to 5 years at $299. I thought it was attractive, considering that a similar package for other brands can cost as much as $600 more.



Both the indoor and outdoor units are one generation before. The latest indoor/outdoor units currently are the Opal SMKM-09/12/18-I-04 range and the SMKY-21/28/32-O-04 compressor range which attain 4 ticks under the ELS (Energy Labelling Scheme)

Cooling Capacity

For those who are clueless on what to look out for when purchasing an air conditioning system, apart from the ELS ticks (the higher the better) the main point to take note is the cooling capacity rated in BTUs.

It may seem that the higher BTUs equals better cooling. However, EnergyStar website states that
"an oversized air conditioner is actually less effective — and wastes energy at the same time. Air conditioners remove both heat and humidity from the air. If the unit is too large, it will cool the room quickly, but only remove some of the humidity. This leaves the room with a damp, clammy feeling. A properly sized unit will remove humidity effectively as it cools"
Having said that, getting an undersized air conditioner will overwork the outdoor unit (compressor) reducing its lifespan and at the same time unable to provide the cooling capacity needed. Therefore it is best to refer to the recommended BTU to room size chart below

Cooling capacity
(BTU/hr)
Max room size
(m2)
5K
14
6K
23
7K
28
8K
33
9K
37
10K
42
12K
51
14K
65
18K
93

  • If the room is heavily shaded, reduce capacity by 10 percent.
  • If the room is very sunny, increase capacity by 10 percent.
  • If more than two people regularly occupy the room, add 600 BTUs for each additional person.
If you notice, most indoor unit (fan coil) is rated at 9K, 12K and 18K while the outdoor unit (compressor) is normally rated at 21K, 28K and 32K. These are the maximum cooling capacity of the units.

At the same time, a lot of packages will normally pair the fan coil and compressor as such as the total BTU of the fan coils exceeds the max BTU of the compressor. 

For the package I bought, the total BTU for the fan coil is 27K (3x9K) while the compressor can only generate 21K BTU. This means that if all the units are used at the same time, the max BTU the system can generate is still 21K. Therefore the fancoil will generate lesser BTU at 7K instead.

For a standard HDB bedroom, especially one that is with the curtains drawn, 7K BTU should be sufficient as it can cool a room up to 28 sqm in size. That is way bigger than any HDB bedroom that I know of, especially those newer BTOs.

Branded vs no-brand

Midea originates from China hence many consider it as a no-brand and inferior to the Japanese and Korean counterparts. However, some Japanese or even Korean brand products are not made from country of origin and actually made in China too.

Midea may not be as well known as Mitsubishi or Panasonic but Midea actually has a joint-venture with Toshiba/Carrier, a well know HVAC producer, sharing each other's technology. This is the reason why Midea is not unknown to other parts of the world where Carrier or Toshiba has made a mark.

If aesthetics and/or functions does not really matter to you, then getting a branded system may not make a difference. In terms of operating cost, the ELS rating is a good gauge therefore the cost will be the same to operate for systems with the same ELS ratings regardless of brand

Even if you purchased a branded aircon for reliability, you will still have to service it regularly for it to remain in working condition within the warranty period. This applies to any brand too.

Once the warranty period is over, the cost to maintain the system may just be as costly considering the parts and labour cost. It is also possible that after 5/6 years, aircon technology may have improved further warranting that you make a replacement hence negating the investment you have made earlier.

So if the Midea can last for 5 years, it is worth the lower cost after which you can replace it.

You can read my review of the system here