BTU sizes for air con

[poppysdad]

Not sure if right forum, in the market to replace a very old air con unit so off to Home Pro. Had measured our bedroom which comes out at 20 sq metres and then googled many sites for btu recommendations and all suggested between 6-8500 btu. After a lot of deliberation we decided on a 12000 btu Mitsubishi top spec model. All going well with purchase until their salesman eventually asked me for room size and upon giving it to him he insists we need a 15000 btu unit. I dug my heels in by showing him many sites on Google with the recommendations but he’s having none of it. I nearly cancelled the purchase but he insists on coming to the house this evening to check my measurements, I assume he thinks I’m a stupid Falang who knows nothing about anything. However I’m prepared to eat my words, so who is correct the homepro employee or the many sites on Google. 

 

[topt]

if you go on the Daikin site where there is a calculator depending on the variables, sun facing, windows etc you may even come out with 17kBTU.......

 

I have a roughly 20sq m bedroom with a current 13k BTU model. For an inverter I was recommended to go up to the 14kBTU model and not take the 12k BTU model. A lot depends on how insulated/exposed the room is.

 

A lot of previous threads on here and other Thai centric sites..........

[stubuzz]

If the salesman is an ass, go elsewhere. The larger unit will not lower the humidity.

 

[steven100]

does the room get alot of sun ?  is the room usually quite hot ?  

if no ...  9000-11000

if yes ... 12000 - 14000  

I have a new ( 1 month )  Daikin in my bedroom 28sqm and it's 13000 ...and works fine.

[Pilotman]

None of our 6 aircons in our various rooms are right for the rooms they are in, according to the formulas used by the sales staff. I would  estimate that they are all up to 20% less powerful than the figures suggest that they should be.  All work perfectly well and all cool the rooms they are in very well. Our elect bills are very reasonable. 

[stouricks]

If the ac unit is 'underpowered' however, it will have to work harder to get the temperature down by staying on longer. I have two 9000 units in my big living room and was told not to run only one of them. OK, lekky is a bit more, but ac will/should last longer.

Edited June 16, 2020 by stouricks

[whiteman]

But he insists on coming to the house this evening to check my measurements, I assume he thinks I’m a stupid Falang  and he may be casing the joint for his mates ???? to see if you got a 65 inch tv for his mates. ;0

 

[tifino]

2 minutes ago, whiteman said:

But he insists on coming to the house this evening to check my measurements, I assume he thinks I’m a stupid Falang  and he may be casing the joint for his mates ???? to see if you got a 65 inch tv for his mates. ;0

 

... have you just told the world that you have a 65" TV? ???? 

[lopburi3]

It makes a lot of difference if you want a temp of 25 or if happy with 27-28 (as most of us here long time prefer).  My bedroom is 26 sm and last two AC have been 9k models which cool fine for our preferred temps.  Ground-floor with cement tile roof getting sun and a little microfiber insulation on ceiling but no windows now (but even with one 9k worked fine except for one or two days over past decade).  Remember most homes here have little or no insulation (as not needed for winter) so figures for other locations may not be that valid here.  Believe your 12k unit will be fine if inverter (do not want larger units when normal as do not remove water as well).  

[bankruatsteve]

12K BTU is more than enough for 20m².  If he doesn't want to sell it to you, get a Daikin or LG.  Probably better anyway.

[Pilotman]

As an aside, personal choice of course, but I would keep well clear of Samsung and go for Hitachi.  As we know, it's all about personal experience.  I have one Samsung (which I hate) and 5 Hitachi, which are excellent. I have stayed in other places with different manufactured air-cons, but none have come close to the performance of the Hitachi models i have fitted. 

[soi3eddie]

The Daikin (or other manufacturer) A/C calculators are useful. Things like; windows, room size, wall/roof exposure to sun and insulation will all make a difference. Go for the top of the line inverter model at the higher end of the BTU scale and any extra you pay now will be well worth it in terms of efficiency, comfort, convenience and long term power savings. BTW: depending on where you are in Thailand, I would probably not be buying from HomePro - I looked at HomePro but their prices, knowledge, range and model years of air con was nowhere near as a good as a local professional air con outfit. In the end I settled on Daikin from "Teddy Air" in Bangkok and they did a great job.

Edited June 16, 2020 by soi3eddie

[poppysdad]

Just to give more info, floor space 20sq metres, windows facing west and north, rarely have sun hitting room. As Lopburi says we prefer a similar temperature to him, we also never use during the day ever, switch on approx 1 hour before going to bed and depending on how we feel it stays on overnight or we switch off before sleeping and rely on floor fan to keep room cool. I’m more than convinced the 12000 btu inverter model will be more than adequate after reading the replies plus doing more research on the internet. Thanks for the replies everyone.

Edited June 16, 2020 by poppysdad
Used a wrong name

[Crossy]

Yup, I agree with a 12,000 BTU inverter for a bedroom that doesn't get direct sun will be more than adequate.

[Pilotman]

1 hour ago, Crossy said:

Yup, I agree with a 12,000 BTU inverter for a bedroom that doesn't get direct sun will be more than adequate.

mine is 8,000 and is perfectly adequate. 

[steven100]

2 hours ago, poppysdad said:

Just to give more info, floor space 20sq metres, windows facing west and north, rarely have sun hitting room. As Lopburi says we prefer a similar temperature to him, we also never use during the day ever, switch on approx 1 hour before going to bed and depending on how we feel it stays on overnight or we switch off before sleeping and rely on floor fan to keep room cool. I’m more than convinced the 12000 btu inverter model will be more than adequate after reading the replies plus doing more research on the internet. Thanks for the replies everyone.

yes ... thank you and god bless your aircon

[Metropolitian]

I found that roughly the room in m2 divided bt two gives the btu in K not far off.

 

17 m2 room here has 9kbtu and 24m2 room has a 13kbtu aircon. Cooling good and they even get to their pauses.

[treetops]

Get the bigger one.  As with most things in life, it's better to have it and not need it than need it and not have it.

[sometimewoodworker]

6 hours ago, treetops said:

Get the bigger one.  As with most things in life, it's better to have it and not need it than need it and not have it.

Total BS. With a inverter maybe not total BS but close.

 

An oversized AC will not run long enough to get the humidity down. So the correctly sized AC is best.

[Jeffrey346]

Just put a new 12,000 btu Daikin in my 18sm bedroom. Daikin insisted I need a 15,000 btu unit.  The 12,000 does a great job cools quickly without a struggle.

[casey1]

number one question to ask any air con salesperson i Thailand... What is insulation?

 The blank response stare will answer all your questions....energy is cheap here, house manufacture not so good even in simple terms of comfort from best use of materials....anything goes to make 4 walls and a roof...the calculations they use are based on this.. they will say you need the bigger units ... almost twice what a North Queensland Northern Territory home will use in Australia where the normal everyday temperature is 42 degrees.... they are finally starting to understand energy conservation by insulation works both ways cool in summer warm in winter..silly thing is in the same stores selling aircon units you will find insulation... and I mean the good insulation not merely the thin stuff which is working on reflecting the heat.....too much BS on this topic here on Thai Visa.... for anybody looking to make an informed decision ...go look at aircon advice for Northern Australia....clear easy concise without the nonsense spouted here ....

[jonwilly]

15 hours ago, stouricks said:

If the ac unit is 'underpowered' however, it will have to work harder to get the temperature down by staying on longer. I have two 9000 units in my big living room and was told not to run only one of them. OK, lekky is a bit more, but ac will/should last longer.

I worked out the size I required then bought next size higher, for as the above says a machine working on its max, is not efficient overall.

 

john

[stouricks]

12 hours ago, Metropolitian said:

I found that roughly the room in m2 divided bt two gives the btu in K not far off.

 

17 m2 room here has 9kbtu and 24m2 room has a 13kbtu aircon. Cooling good and they even get to their pauses.

Doesn't the height of the ceiling and number of windows and wall construction need to be taken into account. 

[Antiparovian]

Maybe I'm stupid falang but does height of room not enter the equation? i.e. measure room on metres cubed not squared?

 

[Henryford]

Just use the basic rule.

Small room 9,000

Medium room 13,000

Large room 18,000,

If it gets a lot of sun maybe bump it upto the next level.

[Kurtf]

My guess is that the Google suggestions were for a typical western house/room. Don't forget that 99% of Thai houses are NOT insulated at all. I'd go with the Home Pro guy's ideas.

[AtlasAus]

Hey mate,

 

Feel your pain.. Just been through it twice with Numchai. 

As others have stated the current units in my house were undersized when installed, but surprisingly the house does have insulation (it's about 12 y/o) and noticeably cooler than our old house. 

 

For the study we went with a Samsung inverter model, but unlike the previous house have barely used it. 

 

The main bedroom we went with a Midea inverter. Midea was recommended to me by a good friend back in Austalia for a 4 car garage I converted into a studio, it was fully insulated including the walls and worked great. We are use the Aircon at night in the bedroom.

 

In both cases I went with my research as much as the salesman tried pushing other brands (perhaps got a bigger commission) that were cheaper. 

 

The other things I noted was the star rating. Only the Midea got 2 stars, the rest 1 or 0.... 

 

The one great thing here is the install times.... Back home it could be a few weeks, here, consistently it has been same or next day ! Got to love that. 

 

Worth noting too is that Numchai pricing includes STANDARD* installation, and they were by far the cheapest of the big retailers.  

 

* Standard install is very basic, back to back and so many metres of conduit, cable etc. 

PS> I am not associated with Numchai or anything else, just found over the last 6yrs they are consistently the cheapest for electrical goods, usually by a lot. 

[DUNROAMIN]

I have a 40 SM room and have a 1200BTU inverter, has no problems keeping the room cool and does not work hard, Daikin or Mitsubishi OK. Don't listen to the BS sales people here tell you, they are told by their employer to push for bigger model, more money for them.  I googled via a air conditioner company BTU checker, cant go wrong.

Cheers 

[bronzedude]

I replaced the outside compressor unit (everything new) for my Mitsubishi AC. The older unit was over 25 years old and the outside unit made a lot of noise-a hell of a lot of noise. I replaced the compressor in the unit about 5 years ago and it still made a lot of noise. I only wanted the outside unit since the indoor part was one of those long flat units (1.5mx.5m) and didn't want to repair the ceiling after installing the new types of indoor units. I googled my room size (20 sq meters) was recommended 16000 BTU. I had it inspected by a reputable AC contractor and he said that for both to work properly, I had to replace the outside compressor unit with the same BTU strength. He opened the old unit and found it to be 36000 BTU. He called back later and said the if I wanted to replace just the compressor inside the unit 14000 baht, I wanted the entire outside unit (everything new-not rebuilted) 20000 baht. I chose the everything new unit. It works perfectly and has almost no noise louder than a hum. By the way, I went to Central Air in Pattaya for a quote (24000-new), a guy on Threpessit Road said 13500 baht for a rebuilted outside unit. I still chose the 20000 baht unit from the reputable guy.

[seajae]

we have a 24 sq mtr room and use a 14 btu daikin, temp set at 25c and even at that temp it can get too cold at times, the salesman want to get more money from you, probably gets a commision  so the higher the price the more he gets, go to another dealer and get a price