whosyourdaddy Posted August 1, 2004 Report Share Posted August 1, 2004 Am in the market for a new aircon. We currently have a 12000 older AC in the bedroom but would like to upgrade it since it is not "perfect" in the hot season. Every place we go they say we need a 18000BTU unit for the 25 sq. meter bedroom but all the websites say 9000-12000 would be fine. Any ideas??? Link to comment Share on other sites More sharing options...
zzzz Posted August 1, 2004 Report Share Posted August 1, 2004 Depends on hot hot it gets as well as size of the area to be cooled. The web sites are likely to be based on temperate climate, not tropical. I would go w/ the local recommendation. Link to comment Share on other sites More sharing options...
elef Posted August 1, 2004 Report Share Posted August 1, 2004 Hi WYD, I found this rule of thumb: Area (Length x Width) X 65 = BTU/hr E.g. Room size 10ft X 10ft - 10 X 10 = 100ft2 X 65 = 6,500BTU/hr. on a web page from Singapore so 25 sqm = 269 ft2 x 65 = 17 485 BTU elef Link to comment Share on other sites More sharing options...
Guest Posted August 1, 2004 Report Share Posted August 1, 2004 More important is the quality of manufacture, all makers will swear blind that there's is the dogs b....x, but as we all know in Thailand the culture is make it cheap sell it dear. Truth is that generally most are not up to the task. Secondly money is all important, remember the golden rule...buy cheap buy twice. If this is for YOUR home then buy the best you can get, pay a little more for known quality. Ask the bar owners about their choice and performance, but generally the more powerful a unit you buy regardless of size of room the less work it will have to do therefore the longer it will last and the longer it will perform. In the bars they're normally referred to by the ton. A 2/3 ton (not weight) will provide you with all the performance you would need regardless of room size. The mean price for a two ton is approx Bt. 40,000 fitted. This ideal will also substantially reduce the electric bills. HTH teach Link to comment Share on other sites More sharing options...
whosyourdaddy Posted August 1, 2004 Author Report Share Posted August 1, 2004 Thanks. Most of the sites that I read were western sites and I guess that the climate is not as hellish. So I guess 18000BTUs and 30000B it is then Link to comment Share on other sites More sharing options...
.. Posted August 1, 2004 Report Share Posted August 1, 2004 An air conditioner is rated at a standard set of operating conditions to enable a purchaser to select and compare various models before selecting a final product. The rating is given in Btu/Hr, and it is a relative measure of capacity. There are many factors that affect the cooling requirement for a room and we have chosen to produce a base load capacity for as "standard" a room as possible. We then introduce a set of correction factors to enable you, the consumer, to be able to correctly select the right size air conditioner for the job. The base load has been calculated for and outside temperature of 95º F, inside 75º F, 2 people, insulated walls and ceilings, double glazed windows and an attic roof cavity above the room to be air conditioned. It is better to select an air conditioner that is right for the job rather than one that is over sized. In situations where the air conditioner is too large, the compressor will cycle on and off excessively. Whilst an air conditioner compressor is running, de-humidification or moisture removal is occuring. This is an important factor in comfort levels as although a thermometer may indicate 75º F, the humidity may be high and the air will feel sticky. It is better for the compressor to run almost continuously. The base load capacity is given on the attached graph and all you have to do is choose the room size and decide whether the room has a high load due to the sun, or is heavily shaded by trees, awnings or has a northerly aspect. Correction Factors If any of these do not apply, just use "1" in the box. Factor A. Outside temperature Someone in Phoenix will need a lot more capacity than someone in Seattle for the same size room. 85º F Ambient Multiply by 0.8 105º F Ambient Multiply by 1.2 95º F Ambient is the standard, and for figures in between- just scale the above factors. Un-insulated ceiling, single glazed windows. Multiply by 1.5. If there is a room above, not just an attic space. E.g., two story homes, apartment blocks. Multiply by 0.85. Additional loads. Add these to your requirement after all the multipliers have been done. People- add 600 Btu/Hr for each person more than 2. Kitchens- add 4000 Btu/Hr. This is a variable and can be increased or decreased according to the activity levels in this area. Examples Calculate the cooling requirement for a ground floor, 800 square foot room, facing west in Phoenix, Arizona. Construction is 2 story and shading is poor. There are 4 people in the space, and a kitchen is included. Step1. Go to Base Data chart and select 800 ft² floor area. Go up to top line and read from horizontal line the required base capacity. This is 15,000 Btu/Hr. Correction factors are: 1.2 for 105º F Ambient . 0.85 for room above. Add 4,000 Btu/Hr for kitchen. Add 1200 Btu/Hr for extra people. Required size is calculated from: Base Capacity * Outside Temperature Factor * Insulation Standard * Room or Attic Above + Kitchen +Additional People. In this case we get 15,000 Btu/ Hr * 1.2 * 1 * 0.85 + 4,000 Btu/Hr + 1,200 Btu/Hr= 23,200 Btu/Hr. If this same room was in the mountains facing north with a maximum outside temperature of 85º F, no kitchen and only 2 people- the required capacity would be: 13,500 Btu/Hr * 0.8 *1* 0.85 + "0" (no Kitchen) +"0 " (2 people only) = 9,100 Btu/Hr. Link to comment Share on other sites More sharing options...
SingaporeSteve Posted August 1, 2004 Report Share Posted August 1, 2004 If its any help I am building 8 house which consist of some 90 air conditioned rooms at the moment. I have spoken to many people on this subject and have found that based on my seen results that Daikin air conditioing although relatively expensive is by far the best overall. The units are VERY quiet, almost without a sound and the engineering is first rate. For our rooms of that size we are using 12,000 BTU models however the rooms have double block cavity walls and polyeurothane foam roof insulation above the ceilings. I also rate Hitachi aircon which we have put into two houses with very good results but overall I would go for Daikin every time. In terms of price, your looking at about 18,000 baht for a 12,000 BTU model and 25,000 for 18,000 BTU. We have tried in other houses local brands and local brands using Mitsubishi compressors but have found both scenarios poor. The cheap units are noisy over time, drip water and generally look their age in double quick time. For me, I would never steer away from daikin now I have them and see them working. Cheers Link to comment Share on other sites More sharing options...
Guest Posted August 2, 2004 Report Share Posted August 2, 2004 Air conditioners are dependent upon several factors such as (1) the insulation value in the walls (2) the location of the windows (3) the size of the windows Knowing Thailand - I would say your place is built backwards like most of the homes in Thailand. Consider the larger model. If it is an over kill, you can always run it at low speed. If you buy a small unit and it is not enough, there are people on this board who will buy it. Link to comment Share on other sites More sharing options...
Soi11 Posted August 2, 2004 Report Share Posted August 2, 2004 WYD, If the 12,000 BTU unit isn't working up to par on the hottest days, you may want to upgrade to a 14,000 or 15,000 BTU unit if available. An 18,000 BTU unit IMHO would be overkill for the size of room you described. I live in Hawaii and have an 18,000 BTU unit in the living room - it also cools the kitchen and dining room - appox 40 m2. With air conditioners, bigger is not necessarily better - as mentioned earlier, one that is too large will cycle off and on too frequently, doing a poor job of dehumidifying the air, which degrades comfort. It's better to slightly undersize an air conditioner than to oversize it. Link to comment Share on other sites More sharing options...
gummigut Posted August 3, 2004 Report Share Posted August 3, 2004 That was a pretty cool post. hehe, no pun intended! <<burp>> Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.