After reading many threads here on the subject of aircon I have advised my wife (in Thailand - I am in the UK at the moment) that she's probably best looking at either Mitsibushi (Electric) or Panasonic for good quality at a reasonable price.

All I want to know is roughly what size BTU the room needs and what the various models and prices are that fit the bill.

The problem we have is that we don't trust the 'professional' person who has come to look at the room. They say that we need 18,000 BTU (I don't know the dimensions of the room but believe it to be no more than 6m x 3m) and they are trying to push for Daiken which is the most expensive. After much hard work, they are now suggesting the Panasonic CS-PC18HKT which I believe to be one of the dearer options too.

I don't really want to spend more than 20k all in because although it is our bedroom, we are only there for a month a year at most. Not sure if this is realistic though.

Being in the UK and with my wife struggling with them I'd like to find out as much info here as possible to arm her with but all of web searches return Thai script pages that I can't understand. Are there any English language pages with any of the info that I'm after on?

Many many thanks for any advice at all here!

a few topics is this search should give you a start

http://www.thaivisa.com/forum/index.php?ac...onditioning+btu

Thanks Stumonster. I've had another look but I'm drawing a bit of a blank because many threads touch the edges of what I'm looking for but don't quite tell me what I need to know.

Looking again, it does seem that 18,000 BTU is excessive.

Perhaps some people with aircon already would be kind enough to let me know what room size they have and what BTU size they use?

I know it's a more complicated calculation but as the room is being built new with concrete, cement covered walls, proper windows, tiled floor and closed flat cement roof I would hope that it retains the cool temperature quite well and therefore doesn't require something over and above what you might normally expect for a room of that size.

I would go for a 12000 btu for that size room

18 Square meters sounds rather small - that would be less than most hotels where about 24 seems to be the norm. I surly would not expect it to require 18k BTU unit. I have two bedrooms of about 27 square meters but little glass area. One has 18k unit and the other 13k unit and both are fully cooled. Believe I would be looking at 12-13k range for your use (if small to normal size bedroom) - that should be fully adequate, especially at night.

Thanks for this. I will get the room measured and post back.

I just call for a new cleaning contract for the Mitsubishi electric cond I have, papers, brochure out & can answer some of your questions:

My room must be 4 * 4 but high ceiling, I have a closing partition I use when aircond is ON, if not the room will be 8 * 4.

In the models I did want (Wild & Long) they have, size start at 18 BTU / 24 BTU / 30 BTU

I paid for the 18 BTU.

I do not find it to be excessive at all for my usage.

Looking at the chart, it said 18 BTU room Sqm 22-30

When I went there, Mitsubishi did have a 13 BTU (room size 14-22) but not the Wild & Long, I choose the 18 and did not regret it.

Plenty of information on the internet about how to calculate British Thermal Units. a 9,000 BTU would in fact do the job, but it would be "working", go to the next size up for cheaper running costs. alternatively go into any store that sells Air Cond give them the room size and they will calculate it for you, this way you can visit a few stores and see if the information is all the same.

Plenty of information on the internet about how to calculate British Thermal Units. a 9,000 BTU would in fact do the job, but it would be "working", go to the next size up for cheaper running costs. alternatively go into any store that sells Air Cond give them the room size and they will calculate it for you, this way you can visit a few stores and see if the information is all the same.

:D

It doesn't depend on the square metre area of the room but the volume of the room so you have to allow in for the height also.

You also say the room is being built new with concrete, cement covered walls, proper windows, tiled floor and closed flat cement roof I would hope that it retains the cool temperature quite well

Well no it wouldn't. Concrete will retain the daytime heat from outside very well, and then emit it at night. So will the bricks that you use which if they are the Thai red bricks have no insulation properties at all. And on top of that you have a flat concrete roof to absort all the heat of the day also.

So considering that it's the bedroom and you may only use the aricon at night when the heat has already had the whole day to buid up it would maybe be best to tell your wife to get a second opinion from another aircon specialist if you think the first is trying to con you.

It doesn't depend on the square metre area of the room but the volume of the room so you have to allow in for the height also.

not necessarily. it depends at what height the aircon is mounted. in high rooms an aircon should be mounted not higher than 2.5m in order not to waste cooling capacity on the upper air volume which should be left "undisturbed".

You also say the room is being built new with concrete, cement covered walls, proper windows, tiled floor and closed flat cement roof I would hope that it retains the cool temperature quite well

Well no it wouldn't. Concrete will retain the daytime heat from outside very well, and then emit it at night. So will the bricks that you use which if they are the Thai red bricks have no insulation properties at all. And on top of that you have a flat concrete roof to absort all the heat of the day also.

both correct. a flat roof is the biggest problem. but the OP is most probably mistaken by claiming the room is built with "concrete".

looking at the room size only i'd say 12/13,000 btu is more than enough. taking the "flat roof" into consideration i say 18,000 btu for sure.

I assumed that he was incorrect that the room is built in concrete also.

Most likely concrete columns and beams with red brick infill which will not provide any insulation properties against the heat and will emit the stored heat like a radiator at night. (unless he has some external shading)

Thanks Stumonster. I've had another look but I'm drawing a bit of a blank because many threads touch the edges of what I'm looking for but don't quite tell me what I need to know.

Looking again, it does seem that 18,000 BTU is excessive.

Perhaps some people with aircon already would be kind enough to let me know what room size they have and what BTU size they use?

I know it's a more complicated calculation but as the room is being built new with concrete, cement covered walls, proper windows, tiled floor and closed flat cement roof I would hope that it retains the cool temperature quite well and therefore doesn't require something over and above what you might normally expect for a room of that size.

For such a small space (small bedroom ?) 9,000 would normally be adequate ... What do you mean

by a "closed flat cement roof" Do you mean ceiling ?

If you really do mean a flat roof with no shading or insulation then you do have a problem

Naka.

For such a small space (small bedroom ?) 9,000 would normally be adequate ...

Naka.

a lot depends on what temperature the OP wants to achieve in this room. is 26-27ºC ok or does he want the room be cooled to 18º when the ambient temperature is 32º?

no offence meant for the OP and/or other posters who quite often have questions or well meant suggestions when it concerns airconditioning. BUT for somebody who is familiar with the different factors a bunch of questions sound like "i need a car in Thailand to drive daily 50km. which car should i buy?" and then there will be suggestions "buy a fortuner, i bought one two years ago and i am very happy with it! excellent mileage, a quiet engine and my wife loves the car too."

Aircon is for wimps.

I use large large fans on the ceiling - so much more stylish

Thank you for all of the time spent helping me out, your comments are all very much appreciated.

Yes, I did mean ceiling and as for the materials used to construct the inner walls (a small room is being made from an existing large space) all I know is that the walls have been put up and are being covered in cement. Building, alas, is not a specialist subject of mine!

The BTU requirement calculations that I've seen are all quite complex and I don't have the full information to allow me to work it out myself. I now know that the room is 6.1m x 3.8m and is between 3m and 3.5m high. As my wife lives in a rural village she is reliant upon local aircon vendors' advice and my concern is their seemingly finger in the air approach. But we would seem to have little option other than to trust them (a second opinion also recommended 18,000 BTU).

Unfortunately the price quoted for a Panasonic (model CS-PC18HKT) is 28,000 baht and I don't even know if this includes fitting. I've drawn a blank too on trying to find out if this is a fair price as web search results are all in Thai and the English Panasonic website makes no mention of this model. Does anyone know of any way that I can check this price or even look at other 18,000 BTU models (either Panasonic or Mitsubishi Electric) and their prices?

I only wanted to spend 20k!

Edited March 25, 200818 yr by qpgwmh

Here are a couple of calculators, one simplistic the other more technical, for

the first calculator suggest you use south florida as the location.

Calc 1

Calc 2 simple

Naka.

Edited March 26, 200818 yr by naka

I only wanted to spend 20k!

for that money you won't even get a 12k btu delivered and installed.

Aircon is for wimps.

true! and ceiling fans are for poor people

Aircon is for wimps.

I use large large fans on the ceiling - so much more stylish

And you wonder why people don't sit close to you.........

I would strongly urge you to use a 12k unit - you say it will only be used at night one month a year? 12K should be fine for that size room, even if it is the hot season (which it may not be). If not enough you can use small fan to increase the cooling effect. I seriously doubt you can power the unit recommended without serious disruptions to your neighbors if a typical upcountry electric power source. That unit draws over 1,600 watts. Full specs are http://panasonic.co.th/web/pid/2353/Spec

I would seriously consider a no brand unit for such use if cost is a factor - believe they run about 1 baht per BTU to buy. And they should do everything you need. I currently use a fuji aire inside unit on an old (modified) LG outside unit 24 hours a day.

If you buy Panasonic I paid 14,500 baht for a 9k unit installed (not from store - from serviceman) about six months ago so expect you could obtain the 12k unit for 20k price.

Now the OP has told us that the cubic volume is not 6*3*2.4 but more like 6.1*3.8*3.3. My Burmese 100-baht calculator says we are talking about 76.5 cubic meters, not 43.2 cubic meters. This room needs 77% more BTU than originally thought.

cubic meters... more BTU

Just curious, but have you looked for a 2nd hand 2 or 3 year old unit? I bought a 43,000 BTU second hand and it worked fine and was much cheaper than buying a new one.

... 43,000 BTU ...

Thought you'd try to get your bedroom cooler than naam's larder eh?

... 43,000 BTU ...

Thought you'd try to get your bedroom cooler than naam's larder eh?

43k must be a typo. most probably it's a 13k unit.

placement of the secondary ( the heat exchanger ) with split systems should also be a large consideration - make the installer put it where you tell them to.

>>43k must be a typo. most probably it's a 13k unit.

Negative on the typo there Naam

Take into consideration that some of the cheaper units are very, very noisey. If you have neighbors nearby, they may complain. If nobody is nearby, then you should be OK.