hi all, here's a quick guide for buying aircond, hopefully useful to everyone else wanting to buy ac.
Okay the geek in me pushes me on to write this simple guide so that you guys won't make the same mistake as I did (buying without reading!).
So my house has never needed AC before until the crazy Kuching temps hit 36-37 degrees Celsius! Out of this world indeed. Normal day temps have only ever reached 33C before. Nights are pretty cool, about 24C coolest. Because of the very hot weather, I had no choice but to go AC hunting.
As usual, guys never ask for directions right, likewise,because I was melting in the heat so I just went aircond shopping without doing much homework.
I only did my homework AFTER I had bought and installed one unit. Well, I still need at least 2 or 3 more units including one 2.5HP unit for the living room.
Here's what I've learned from browsing the forums, trawling for user comments and feedback as well as asking questions here and there.
1. Size your room correctly! A quick way to calculate aircond cooling capacity for your room is:
i. find volume of room in cubic feet - length x width x height and multiply by 6.
ii. add 500btu per person in the room to this figure.
example. 12' x 15' x 8' = 1440 cubic ft. multiply by 6 = 8640. add 500 for one person = 9140. This means the room needs an AC unit of about 9000btu/h to cool it properly.
This is very important as a unit with cooling capacity too high for your room will turn on and off frequently (when the compressor turns on, it draws A LOT OF power compared to when it is running normally, just like turning our PCs on and off frequently, you wouldn't do that right?) and unable to remove moisture from your room efficiently. A unit too low will take a long time and consume a lot of power to cool your room. So size and match your room to aircond capacity properly!
2. pay attention to the (energy efficiency rating) EER number on the unit's specification sheet. Avoid brands that do not furnish this number either on their website or product brochures. The higher the EER the more efficient it is (uses less power to do the same job as lower rated ones). To calculate EER, take the btu and divide by the unit's power input in watts. example, 9000btu/900watts = 10 EER. In general, buy units with 10 and above EER.
3. Be careful with btu/h numbers, some companies round this number up. Pay attention to the cooling capacity in kilowatts. 1 kW = 3.412 btu/h. My new SHARP is listed as 9000btu/h but on the compressor, it is listed as only 2.5kW meaning it really is only 8530btu/h with an EER of only 9.22. Bummer!
4. Inverter units are not worth the extra cost in purchase price, installation and maintenance. They will only save $$ if run continuously at temperatures around 26C or 27C and if the room is very well insulated. So if you run your aircond infrequently (only on hot days) and at 24C, it's best to just buy a normal non-inverter unit.
5. Even though units with high EER may use less power (such as the 5 star energy star panasonic models), they cost a bomb and it will take several years for you to recover the difference in cost in terms of savings unless you run it everyday for 10 or more hours per day (such as office environment). For example, even though my Sharp has a lower EER rating it is cheaper than a similar Sharp unit with high EER but costs about 300-400 more. Using a convenient excel calculator, I can save about RM50 per year based on normal usage which, in theory, means it will take 6-8 years to recover the initial cost. This does not take into account servicing costs. So decide what suits you.
6. Finally, do not ever buy based on looks alone (LG). Sifting through the forums, it seems the korean brands Samsung and LG are not reliable. LG seems to look good only but many complaints of water leaking etc. Panasonic is a bit of a hit and miss (because the components are sourced from china) but generally reliable. If you think today's Panasonic is comparable to yesterday's National, think again. Avoid cap ayam brands such as Akira and Haier. Aircond installer and service man told me Sharp is good soI hope he is right. My next two or three units will be York.
So in conclusion, go for higher EER units that don't cost a bomb (normal York 1HP units are rated at 10.2 EER and cost only RM850-RM900 with installation) and are known to be reliable.
So far I am okay with the new Sharp. It has a nice cool LED temperature display on the indoor unit which shows either room temperature (like a built-in thermometer) or set temperature. This LED also can act as a night light for the kids room and can be turned off.
It also has a quick-cool function and is able to cool my room down to 22C in about 3 hours from 29C. It takes an hour to go down to 24C from 30C. I can let it go to 22C and turn off automatically after 3 hours and my room remains comfortably cool right till morning.
There is also a power switch on the indoor unit for AUTO mode in case the remote control is lost or misplaced. However, I'm now looking at York for the living room and other rooms.
Geek out!
This post has been edited by mzms: Aug 14 2009, 06:31 PM 
Jul 14 2009, 06:25 PM
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