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Air Conditioning in Thailand

2 May 2019

This article applies anywhere of course whenever one is trying to cool a home, not just Thailand. It’s a bit ironic because the reason I am spending time writing this post is that it’s 40 degrees (104 F) plus outside and so in these sort of temperatures I retreat to the cool of inside (27/80 degrees) and do some work on the blog.

The most comprehensive reference manual on building a house in Thailand. An e-book of 120,000 words arranged in a number of sections including the initial planning stages, a daily report on the construction process, later updates after we move in, a few summaries and a section on more general background topics such as land titles, Usufruct contracts, utility expenses and the daily cost of my building project.

So, what will you find here?

Firstly, I am a retired government employee not a builder so you won’t find a very specific how-to building book full of technical details. However, what you have bought is a very detailed 884-page coverage of how an enthusiastic amateur like me survived the Thai building challenges and ended up with a wonderful home that I still find hard to believe I have achieved.

Although the house we built is unique to us and may not be anything like the style of dwelling you plan to build, you will find many of the processes, frustrations and hints I share very relevant to almost any domestic construction project in Thailand. Topics covered such as creating a cool house, planning and design tips and specific topics like septic and water solutions are mostly likely generic to your situation, or parts of them will be, so will be a useful addition to your research material.

I have tried to make the book a good read and not just a dry list of dos and don’ts. It is written in a casual style as though I was chatting with you and I hope that makes it more engaging. In each chapter you will live every individual day of the build with us plus some of other events and activities and share our excitements and frustrations. Even if you aren’t about to build in Thailand, I believe the book includes enough interesting material of one farang’s story to hold your attention.

Find out how to obtain the e-book HERE and lots more information including a free sample chapter HERE

I am loving your book – just on my second read at the moment, to make sure that I didn’t miss anything first time around (which actually it turns out I did!).  

Just a note of thanks at this point ……. I am a fairly methodical sort of bloke, but there are many issues which your book highlights which I just wouldn’t have thought about – or if I had, I may well have assumed they were “standard” building practice [U-bends, drain positioning, barge-board alignment] – if it hadn’t been for your excellent descriptions!!  I will probably still “miss” something – that’s the nature of building/design – but thanks to you, it shouldn’t be anything too mission-critical. Mike

Undoubtedly, we would not have the quality home we now have without the book, we had no idea even where to start until we found Building in Thailand eBook. We did manage to avoid most of the traps that we could have fallen into, we are extremally thankful for the authors attention to detail and common-sense approach. Chris

I have had the good fortune to have used the first edition as part of Yuri and my plans to build our home here in Surin.  To say it is a good reference book is an understatement.  The practical advice and your self deprecating style make it a great read.  The anecdotes and asides all add to its appeal as both a “how to manual” and a fascinating insight into what lies ahead for people like me who have only just commenced a similar journey. Far better armed for what’s to be encountered. Greg

The income from my eBook pays for the upkeep of this blog, which is otherwise commercially free unlike so many others.


Our lounge room. Windows that connect you to the outside but are sited so as not to allow any sunlight to enter the room, overhead fans for quiet air movement and air conditioning for the peak heat times of the day.

Regular readers will know of my obsession to encourage people to design and build a cool house as the first defence against long periods of extremely hot weather. If you have a look at the temperature chart below for our home-town of Si Bun Ruang April 2019, this is a serious heat, not just a one or two-day phenomenon but as an everyday occurance for weeks.

I say it every time I write on the subject but it is a complete mystery to me why expats ignore this long-term heat reality and continue to build Thai-style houses that rely 100% on air conditioning to keep them habitable. I am sure that there are farang who are happy to live in constant heat but I am certainly not one of them.

April 2019. This has been a particularly fierce hot season arriving early and with higher temperatures.

Air Conditioning Unit Size Calculator

My thanks to for this calculator. It has been designed for Australian conditions but if you select the city of Darwin, which is a tropical state capital having the closest climate conditions of Thailand, you will get pretty close.

BTW, when I used this calculator I downsized the recommendation by one size 9,000 BTU in the bedrooms instead of 12,000 BTU etc) because I had confidence that my house would be so cool I could get away with smaller air conditioners. I was proven right. 

I am not an expert in air conditioning but a happy user of it when necessary. I have done the research for you and have added other people’s words with acknowledgement in the headings below combined with my actual experience.

Inverter Air Conditioning

I chose inverter air conditioners, not so much for the power saving but because they are extremely quiet in operation. I have a ‘thing’ about noise so this was a priority for me but won’t be for others. Inverters are much more expensive to buy and more complex in their operation so the power savings may take some time to balance out the initial cost. However, for me, having air con that ticks over in the background is a price worth paying for especially in the bedroom. I have been in hotels and resorts where when the non-inverter air con kicks in it wake the entire neighbourhood.

My thanks to this Singapore air conditioning site HERE for the following article

Inverter Air Conditioners are newer  in the market and they usually come with a different rating. While non inverter aircon have energy efficient rating, inverter aircon are marked with inverter rating. Let’s take a look at the basic differences between inverter AC and Non-inverter air conditioner

Function Of The Inverter:
The biggest difference between these two types of aircon lies in the functionality of the inverter, the best tool to save electricity. The inverter in Inverter aircon helps to control the speed of the compressor motor, thereby changing the temperature as per requirement. This can reduce the electricity consumption of your air conditioner While in Non-inverter air-con’s the compressor motor it operates at complete capacity or non at all and switched off. This can cause unwanted current consumption and high electricity bill.

Difference Between Compressor Units:
How much heating or cooling is needed by your AC unit varies a lot depending on the external temperature and the internal temperature of the room. Inverter air-con’s generally operates by a controllable compressor unit. When cooling or heating capacity is needed to be increased, the compressor works at a high speed that increases the quantity of refrigerant. On the other hand when normal temperature is modest, the compressor operates at a low speed and reduces the amount of refrigerant.

However in non inverter air conditioners, there is no way of controlling the compressor. It operates either at full capacity or none at all. When high amounts of refrigerant are needed it turns on, while the need is low, it turns off, causing unnecessary energy consumption.

Eco Friendliness:
When compared to non inverter air-con’s, inverter aircon are much more friendly to the environment. Inverter aircon can detect sudden fluctuation in the room temperature, which leads the compressor to slow down or work faster. As soon as the room temperature reaches the set temperature, compressor slows down, thereby maintaining a constant temperature. This highly helps to save energy. Generally inverter air-con’s need 30-50% less electricity than non inverter air conditioner

Money Always Matters:
The only drawback of inverter air conditioners is the huge price. Initially, the unit and the installation cost a lot than non inverter aircon. But when you think about it in details, you will see that the price is justified. Inverter aircons save up to 50% electricity than non inverter aircons. So, if you are planning to use AC for a long term, buying an inverter AC will be better, cause in the long run, the money you would be saving on electricity will make up the huge price.

Difference Between The Unit’s Working:
The short it can be said that inverter aircon are more precise. Non inverter AC provides a fix heating or cooling by a fixed power with the compressor running at a fixed speed. The compressor has to start and stop when required. On the other hand inverter aircon have a controllable compressor that provides the exact amount of heating and cooling as needed. So, in terms of efficiency and precision, inverter air conditioners are much better.

This bedroom got early morning sun but we have planted outside to stop any sunshine getting inside. You get the benefit of the view without the heat.

I can’t say how much money we save having inverter units over ‘normal’ air conditioners but I can show you the benefit of efficient air conditioning when they are combined with a cool house design.

The last six months average temperatures have varied as follows below (yes, we do have a lovely ‘cool’ season in the northeast) and I have shown the electricity bills we paid for each month:

Nov 2018: 28 degrees/2,312 baht

Dec: 26 degrees/2,294 baht

Jan 2019: 26 degrees/2,467 baht

Feb: 32 degrees/2,301 baht

Mar: 34 degrees/ 2,586 baht

Apr: 36 degrees/2,974 baht.

Please note that our power bills also reflect the fact we run a 60 sprinkler garden watering system powered by two large pumps that are run every day as the heat increases. So from the cool season, when we mostly didn’t use air con, to April when we use it every day plus all night in the bedroom, our power bill, including the watering system, has increased by 700 baht or A$30.00 a month. Not bad.

Both the compressor unit and the kitchen gas bottle neatly hidden to minimise ugliness 🙂

The Dry Mode

When selecting an air conditioner it is worth looking to see if the brand you are interested in has a ‘dry’ function mode. Basically, this is a low-cost way of running the air con using it as a dehumidifier with a bonus of cooler conditions at a low running cost. I have borrowed other people’s words again to explain. This time my thanks go to this site HERE:

Air conditioners are very convenient devices especially when the temperatures are ridiculously high. When it is cold you can do something about it – wear as many warm clothes as possible. However, when the temperatures become unbearably high, there is only so much you can do about it. Removal of clothes has its limits. A good air conditioning system comes in really handy as it will keep the cool air running in your home and office to make life all that much easier. But what if you have no idea on how to use it? For instance, very few people know how to use the dry mode function that comes with most air conditioners nowadays.

What Is The Dry Function Mode In Aircon?

What exactly is dry mode? 

Dry mode is often compared and confused with the cool mode. To some extent they do not feel different. Nonetheless, they are very different in terms of function and the result- even the remote control will tell you. On the remote, the dry mode is shown by a symbol which is a water drop on the other hand the cool mode symbol is frequently a snowflake. The dry function, as aforementioned, is not a common feature of all air conditioners. It is mostly on some varieties of central air conditioning units and window units. The main point of the dry mode is to reduce the humidity in a room. As you probably know, an increase in humidity translates into an increase in temperature. When it is humid, temperatures even those that are relatively low tend to be a bit too uncomfortable. 

So, basically the dry function reduces the temperature in a room by lowering the humidity. This function is most convenient during those times of the year when it is humid for instance during the rainy season. During this season the temperatures might not be hot enough to necessitate the need for cold air. The humidity however, is high and quite irritating. One point worth noting is that the dry mode is not meant to remove all the moisture in the room. 

The working of dry mode 

When the air conditioner is function in dry mode, the fan and other inner components of the device will be running. However, the unit does not blow out any cold air. The air in the room passes through the air con and the water vapour condenses on the evaporator. Dry air will then exit the unit and flow back into the room. This working of the dry mode is almost similar to that of a dehumidifier. A standalone dehumidifier can be found at just about home improvement or hardware store. This one is better than the air conditioner working on dry mode in the case that you are working on a large room. The air conditioner will only remove some moisture and not all.

Assuming that the thermostat is set to 25C and that the humidity in the room is about 90%, the air conditioner will reduce humidity till the temperature is 250 C in that room. When the air con is switched on, the fan will start running to suck in the air and the compressor cuts in to facilitate the condensation of the humidity. Once the room temperature has dropped to 25C then both the fan and compressor will stop. Humidity rises steadily again and so does the temperature. When the temperature goes to 26C the unit starts running again- the cycle repeats itself. 

Cool or dry- which is better? 

Cool mode works almost similar to the dry mode only that when the temperatures drop to 25C the compressor stops running and the fan is left on alone. In dry mode, it is all about keeping the relative humidity at a comfortable 60%. This happens in both the cool and dry mode but in dry mode this value is maintained. In cool mode, humidity keeps increasing dramatically as the fan continues running. Benefits of using dry mode include: 

• Lowering moisture in the room significantly

• Maintaining comfortable temperatures without really cooling 

• Energy efficient

Dry mode does not really cool the room. The cooling effect comes from the removal of excess moisture not that the unit is actually cooling the room. By using the dry function of your air conditioning unit you will be spending less money on energy bills. It is a really effective way of keeping the temperatures comfortable.

We ended up buying Mitshubishi Electric inverter air conditioners, two 9,000 BTU for the bedrooms, one 12,000 BTU for the kitchen/dining area and an 18,000 BTU for the living area. Thye all have a ‘dry’ mode and I have to say it works really well. I only use setting and the house is maintained at a very comfortable 27 degrees 

Photo taken at 3:00 pm. 27 degrees inside with air con running on ‘dry’ and fan on lowest setting. Outside 38 degrees, with the sensor in a shaded insulated area so add a couple of degrees. You will also note that the humidity inside is low as without the dry setting it sits on about 65%.  

I hope this post adds to your knowledge, for those of you who are thinking of living in Thailand at some stage, and is of general interest to others.

Please leave a comment. It makes my day or otherwise make a supreme effort and click the ‘like’ button!

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  1. Roy Leslie

    Would anyone have a contact for fitting solar powered air con. I’ve saw one guy on social media but can’t get hod of him. I’m in Prakonchai, Buriram.

    • Tony

      Do you know a company in the Nong bus lamphu or udon thank area who do reverse cycle split systems?

      • Tony in Thailand

        Do you use Facebook Tony? There’s a local NBL group that might be helpful: I bought my air con locally in Si Bun Ruang, but researched the prices first to get a comparable deal.

  2. Es

    Is one better for the ocean environment. specifically part degradation. Local air Macanic told me the non inverter is much more reliable. But you never know if that is because he doesn’t have stock of that one…

    • Tony in Thailand

      Yes, a non-inverter is less complex but the advantage of inverter with very quiet operation and lower running costs is a big plus for me.

  3. Dave

    that the airconditioner size calculator is one of the most handy tools around.
    Agree that selecting Darwin as being the most similar climatic Australian regional equivalent to Thailand from the list.
    But, as Thailand lies in the northen hemisphere you need to invert the compass points. North becomes south , south to north, north west to south west etc etc but East and West inputs remain the same.
    would expect the further north you are in Thailand the more important these changes would become.

    • Tony in Thailand

      I am glad you found it useful, or maybe you have already found it yourself. Thanks for the reminder to people to change the hemisphere for Thai expats. A bit confusing otherwise.

      I appreciate the comment.



      • Bill Gaudette

        Tony, my fiancee wants to cool her current home in BKK, problem is home is open on one end, one block wall in back other two are loose wooden walls and other is open to outside and cannot be closed in. Trying to advise her on what AC could possibly work in this type of poorer home construction. Fans just not doing the job but I cannot imagine a wall unit will be very effective, any suggestions as everyone wants to sell her these high end units we’d we’d use back home.

        • Tony in Thailand

          That’s quite a challenge Bill. Obviously the ideal is to at least have walls that are complete and don’t let in too much outside air. The situation you describe sounds as if brute force is required because of the loss of cooled air through the front and side walls. Is there any chance of at least sealing off some of that space so that you can have an effective air conditioned space and an area that is only fan cooled, maybe for mornings and evening when the temperatures are lower? My house is super insulated but I still have very underused air con in the living areas. If I had to I could comfortably live in those spaces just with fans, and in fact do just that for most of the year, but I do use the cooling in the bedroom most nights. Would a split design like that work for you? Otherwise you are stuck with large capacity and large cost to battle the amount of hot air in that space.

          • Bill Gaudette

            Thanks Tony, I have tried to close things up, it’s rather frustrating for me as they are a poor family, its merely a metal roof. I could close things up a bit more so that much of the cool air would stay in the sleeping areas but with so much cool air bound to escape I cannot image the unit every slowing down nor shutting off!! and when I’m not there as I am not there full time just yet, they’ll probably leave it on 24/7 so eating electric I am afraid and the unit they are pretty intent in buying is 19,000 baht so it will not last long at that rate and is just a waste of money, I feel.
            I do intend to purchase a piece of property, I have tried to push for property NOT in or near BKK as I’d love to live in Non Din Daeng, about an hour thirty south of Buri Ram where I have a couple freinds but they can’t seem to part of family in BKK. That’s why my interest in your building plans as I will eventually build – somewhere!!!

          • Tony in Thailand

            Bill thanks for getting back. For some reason I didn’t get notification of your reply so am way late in responding. It sounds as if the air conditioning will end up a no-win situation. I look at Thai building standards, even ‘proper’ houses, and the wastage in electricity powering cooling for badly design homes must be enormous. Very sad to see when the alternatives are easy to research. Like you say people with such little money don’t have the luxury of doing more than basic shelter.

            I must say that I am with you on building somewhere a bit quieter and most likely cheaper than BBK. I haven’t been to Buriram but a lot of farang base themselves that way. We had a friend visit us and his wife is from there. She couldn’t talk Isaan and my wife can’t speak Buriram so they both had to resort to Thai! One country but many dialects.

            I hope you get settled one day. Keep in touch.

            Cheers. Tony

  4. Ted Lesher

    I presume your sprinkler system is automated. Where does one find controllers, valves, etc. for such a system in Chiang Mai?

  5. Ted Lesher

    Hi Tony, I presume your sprinkler system is automated. Where in Chiang Mai does one find controllers, valves, etc. for such a system?

    Thanks, Ted

    • Tony in Thailand

      Hi Ted. No, they are on a manual system. We have seven different zones that get about 10 minutes of watering each. I could automate it but we have the time and sometimes simple is better. I time switching between zones with topping up my evening drink, so all good 🙂 I have a friend in Udon Thani and he installed a full automated system but he’s away more than I am. As far as I know he got everything from Global House, who have a garden watering section. I will check with him and let you know.

  6. Nobby

    Fascinating reading Tony will have to certainly think about Inverters as and when I have to replace any of our aircon units!


    Chris and Nong

    • Tony in Thailand

      Thank you Chris. I am pleased that was useful. As air conditioning is such a central part of life here I think the extra expense for an inverter is worth it because of the way it operates.

      We have hit cooler weather after a few days of late thunderstorms with decent rain. No sprinklers for three days! Isn’t it funny when the definition of ‘cooler weather’ is mid-30s, which is what it is now. I might have to dig out an extra doona for tonight 🙂

      Cheers mate.

  7. Jim Busby

    I guess this is part II of your “Thailand is Hot” Post from March. Yes, good insulation is key for the roof/attic and good sealing windows and doors too. Variable speed motors are the rage for all things motorized to save energy and components. I notice that you have wall mounted units, which I have seen in most other people’s photos, and was curious whether anyone opts for full house air conditioners with ductwork? I am fortunate to have a drier summer climate where I can open the windows at night when/if it cools down. I put box fans in the windows to draw in the cool air, and then close the windows the next morning to keep it cool for much of the day. Of course, with my windows open, I am not expecting to be awakened early the next morning by Monk or Village announcements over a loudspeaker at dawn, just raccoons playing in my pool. I love the dry mode example where the superscript doesn’t work for 25C and comes out 250C. I was going to say that’s exactly where I set my thermostat for my vacation house on Venus.


    • Tony in Thailand

      Hi Jim. I had forgotten about that connection but will link the two now that you have raised it. I did come across a home that had the full ducted system but the vast majority of houses I have seen only use the individual units. It’s funny because in Canberra I had a central ducted heating system (gas) but I never even considered looking at a central cooling system here. I think from vague memory that we did the air con in stages. The two bedroom units went in first. I then decided later that the kitchen/dining area needed help and we installed the 12,000 BTU. The 18,000 BTU in the lounge area went in the next year (?) I originally wanted to trial the house to gauge how comfortable it would be basically without air con during the days. It is certainly livable just with fans but more so with a bit of cooling. It’s 10:00 am here and we are at 35 degrees already. Inside is 28 degrees (no air con).

      I suspect that many people, myself included, come to Thailand with the ‘open windows at night to let the cool breeze through’ mentality. In Canberra,which is 1,900 feet above sea level, summer evenings did cool down and we often opened up the house in the evening before shutting it up with closed curtains before going to work to trap the air inside. Here, outside temperatures may get slightly cooler than inside later in the night, but when we go to bed it is often still cooler inside. As I have mentioned before we get NO breezes at night so opening windows has a lesser effect. The final aspect many might not consider is that Thai people are extremely superstitious and trying to convince your partner that having a window open at night thereby giving spirits access to the bedroom might lead to you sleeping alone 🙂

      You are also right about the noise. I know I am super sensitive and others don’t care, but what’s the point in installing double glazing to keep the noise out if you then open windows up at night when the dogs are at their loudest followed by the early morning roosters and loudspeakers?

      With another burning day on its way I suspect there will be another post for you to comment on later! Thank you as always.


    • mark

      G’day Tony thanks for another great read, if I may I’ll butt in and tell Jim my experience on ducted aircon. G’day Jim I live in the north west of Western Australia that has very hot and quite often humid summers. In the town I live most of the houses originally had ducted aircon’s installed. They cost a lot lot more to run than splits and are a lot noisier to as well. If your ducted breaks down you have no aircon, with splits e.g if your bedroom stops working you can make do sleeping in a spare room or the lounge for a few days. When I bought my first house up here the first thing I did was pull out the ducted unit and put in splits, a lot of people have done the same thing. If there is one couple living in the house there is no need to pay a lot extra to cool the whole house. I have since sold that house and am living in a rental as I don’t want to retire in this town as my goal is to retire in Thailand, The house I’m in now has ducted. From winter to summer my power bill more than doubles and that is using the aircon sparingly, I only turn it on at night for sleeping and on weekends during the day if i’m home. And the thermostat is set to cool 25 the house not make it cold18 Ducted aircon would be nice if you were filthy rich and didn’t have to care how much you spent.

      • Tony in Thailand

        Hi Mark. Thanks for your reply to Jim. I hadn’t thought of that aspect to central ducted – all in or nothing. I think you can zone them but I doubt that would be to individual rooms and there would be extra costs involved I am sure. The possibility of losing all air con with a fault in the central system is a good point too. I am typing this reply in the ‘office’ in the main bedroom and we have the air con on ATM set to 26 degrees. The rest of the house is not being cooled so no cost.

        Best regards.

  8. Frank Bond

    Hi Tony, you’ve certainly put some thought into this article, it’s appreciated. Now I know what dry mode does! The importance of proper building techniques for humid countries is a must as you’ve said before, otherwise any AC unit will be so inefficient. No wonder some westerners drink so much beer to knock themselves out to sleep!! Cheers Frank

    • Tony in Thailand

      Thanks Frank. I come across some of this information by accident so I am not trying to sound like an expert. Always try to share whatever I pick up along the way. I only discovered the ‘dry’ mode this season because I am a typical male and don’t bother to read the instruction manuals 🙂 Oh well, better late than never. 10:00 am and it’s 35 degrees outside. If I leave the air con off maybe I will need a beer shortly!

  9. Daniel

    I always wondered about dry mode. Of course, cool mode also acts as a dehumidifier. And dry mode seems to blow cool air. Anyway, my air conditioner has a heat mode too. These things are getting complicated.

    • Tony in Thailand

      You may have got people shaking their heads about the heat mode Dan but as you know the evenings and early mornings during the cool season in the north can get very chilly by ‘normal’ Thai standards. The insulated house works in reverse as we walk from a warm interior to a cool outside for morning coffee. Bliss!

  10. Mike

    Thanks Tony! I’m a fan of fans year round but it’s definitely not cool to be without aircon during the hot season. I’d also recommend the inverter unit FWIW.

    • Tony in Thailand

      We use fans mostly during the year but in this heat a touch of air con is bliss. Because it is so cheap to run why not?

      Thanks Mike.

  11. Bob

    Thank you Tony for your valuable information.
    I have miss placed one of my manuales.

    • Tony in Thailand

      Do you have Mitsubishi Electric? I can give you a copy if you do.

      • Jon Rogers

        Hi Tony,
        Really enjoyed this article! Before moving to Thailand I lived in the USA at 9000ft in Colorado so I never needed airconding before. We’re getting our land ready to build a house here in Isaan and this article was very informative for me.


        • Tony in Thailand

          Hi Jon. Yes, where I came from we were nothing like you but it was 1,900 feet so even in the summer the evenings were often cooler and one could open the house to let the air inside. OUr summer temperatures used to hit 40 degrees C but only for a day or two, nothing like the weeks we get here. One can survive here without air but it is so much more comfortable with it, especially in a bedroom at night if nowhere else, and I think that comfort is a built-in aspect of retirement!


  12. Geoff Anstey

    Hi Tony

    Very good timing with your info, we are close to putting up the roof. Thanks.



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