Air conditioner bafflement

[Nuddy]

I wish to help you as well and I reckon the TVers on here are correct about checking room size and converting that to BTUs and to then go look at whats available.

I lived in two different houses here in Thailand before and am now in my third home. This one is owned by my wife (funded by u know who) so I brought the air conditioners from each property as I moved on. In this, our last home I hope, it is larger and on the advice of the local aircon guru we placed the old units in rooms suitable to them.

Being a larger house than we previously had I did need more units. I had before one LG and two Mitsubishi. All proved ok to move in and work well. So I bought more Mitsubishi's. Never had any other brands so I cannot comment other than on these. The mitsubishi's work better than the LG which gets there but takes a bit more time.

One thing is that you need to buy from the local shops rather than going all around Thailand chasing a deal. Why, its because of the servicing. All these units need a power flushed water bath every year to continue to work properly. Some need re gassing every two years. Choice of your retailer is important as well. Its no good buying a Mitsu from a guy who majors in LG and vice versa for instance. The Mitsus are a bit dearer for same btu quoted but last longer and tend to eat less electricity. As I said they all need a bath every year and sometimes re gassing.

Regards

[mikiea]

I've done that - I'm just seeking corroboration from those with experience that the figures I have come up with seem correct and I haven't overlooked anything, plus answers to all the other questions

answer to question 1, you do not know how a/c works, it always takes the moisture out of the air, thats its job, thats what it does, i do not understand the cool humid feeling you want, maybe you should look into a water air cooler. oh and do not try to save a few bucks by buying smaller, they run longer & the cost is greater on the ele. bill.

[manarak]

9000 and 7000 inverter units are adequate for the sizes of OP's rooms if the walls receive no energy from the outside.

If the walls receive direct sunlight and are simple layered concrete or brick, more power might be required.

The best practice is to insulate the room, ideally have temperature-blocking wall structure and keeping the outer walls in the shadow.

[laislica]

I fully cool my bedroom with 9k unit and it is about 26 sm so your largest at 18 sm should be fine at 9k (I use 24 hours but ground floor and no large windows - for night use 9k should be fine and probably most days. 9k is about the smallest unit so would get same for both rooms. If only one to get much use would get inverter for that. Recommend you have air conditioner professional clean every six months (here in Bangkok one even 10 months has resulted in complete blockage for fan coil unit - and fliters were cleaned weekly). There is a lot of dirt that gets through and needs to be removed with pressure cleaning.

I have two Panasonic 9k units (normal compressor) and one Mitsubishi 9k inverter that all seem to work well. (and are replacements for much larger units - normal recommendation is over the top here unless you want meat locker temps (but some seem to want that). We prefer temp in the 26-27 degree range - if you want low temps then the stronger units will be required.

You may find a local person who maintains units can sell you a unit at a lower price as some have wholesale access.

You can clean the filters in the heat exchanger inside the room.

Just open the cover and take the filter out to wash and dry it.

You will be amazed at how much lint and dust can clog the wiremesh.

If it becomes too clogged, safety circuits will stop the unit from running at all.

Your wife will easily find a local "Man" who will service the outside compressor unit, he will check if it is losing any gas as well as the pressure wash.

My wife used to like the temperature set to 24-25C and it was way too cold for me!

What's the point of having to put extra clothes on the bed whilst you pay a lot of monney to freeze yourself?

I have now got her to be comfortable at 27 - 26C.

Someone else pointed out that the constant drone of the fan can be a sleep aid, drowning out intermittant noises from vehicles, dogs, gecko's etc.

We run the fan at top speed to achieve noise suppression.

Set at 26 before we get into bed and change to 27 for the rest of the night.

We winter in Thailand and Summer in Spain. We need aircon in both places except, in Spain we have the option to heat the rooms, essential for the winter.

If I lived in Chiang Mai/Rai, I would consider asking the local aircon vendors about that.

[bangmai]

the life of a compressor on a mini-split is going to be less than 5000 hours.....that's why they push so many btu here....the more it runs, the quicker it wears out. To prevent short cycling, which happens when the unit is big and powerful, you need to set the differential on the thermostat to the max, which is usually 1.5c (was 3F on Honeywell). A ceiling fan on low speed is a great complement to an a/c, and will keep the living areas more consistent. Adding refrigerant is a myth and indicates a leak. My parent's is 20 and has never had refrigerant added. They live near the USMC Jungle Warfare Training Center, so it gets used, but much more seasonally than here. Buying something that "works good at night" or "most of the time" means you are undersized. It should be able to cool the entire room on the hottest day of the year. For some reason life-long renters always feel the need to run them excessively cool, and if they do that on an undersized unit; it's going to overheat and die.
"

[GOLDBUGGY]

I think you are quite accurate with your estimates. I have a 13K BTU Unit which is a bit of an overkill. But the hottest days haven't come yet. My room also doesn't have the large windows and is in a shaded area, so a 13K for you might be the best one to get.

There are 9K Units around but I haven't seen many. Part of the reason mine is an overkill is I have only been using it at night and set on 25C. The main maintenance is the regular cleaning of the dust filter located at the front of your AC Unit. I have my AC Unit recharged yearly, plus have then do an outside cleaning. Professional AC Maintenance is cheap here so use them.

[recycler]

I would go for Mitsubishi inverter types, than the dimensioning is not a big problem if you have too much capacity. But you better have them a bit over dimensioned than too small, if it's too small it will be running full all the time and cost you more than a bigger one running low.

We have a few installed in the house and they are the most silent, great for bedroom use.

Since we replaced the older Amena in our bedroom with a Mitsubishi Inverter we use it much more and I don't see it on our bill.

[IMHO]

9000 and 7000 inverter units are adequate for the sizes of OP's rooms if the walls receive no energy from the outside.

If the walls receive direct sunlight and are simple layered concrete or brick, more power might be required.

The best practice is to insulate the room, ideally have temperature-blocking wall structure and keeping the outer walls in the shadow.

There's no such thing a 7000 BTU inverter - so what units of measure are you talking? HP or kW both seem a bit excessive

[rapom]

Just hunt around for prices, sometimes an a/c shop gives better service.

Just picked up a new model 12 Samsung at Big C for 10,900 installed. Once the real heat hits prices usually go up.

The Big C in Surin, has put up a new display of AC units, in the last 3 weeks, with some good prices. I brought a Carrier 18000 btu in Feb. for 17,000 baht delivered, that was marked down from 28,500. Over 8,000 baht cheaper than Home Pro or Power Buy. I also brought a Hatachi refrigerator, on sale for 2,000 baht less than the competitors.

[oldmanofhoy]

This is the most accurate AC sizing guide I've found, based on real world experience: http://www.rung-ruengair.com/new/InformationAir.html

The website may be accurate, but it is unreadable.

Take a look at the website using the Google Chrome browser and it will do a machine translation of the content from Thai into English. It's a statistical-based translation so hardly 100% accurate, but I find it's usually enough to get by.

Many thanks for all the reponses and in particular this reference - it's exactly what I was hoping to find. I now feel I understand a lot more about the entire process and how many BTU are required. I have decided to go with 12,000 BTU with inverter for the main bedroom, and 9,000 without inverter for the spare bedroom, on the grounds it will get much less use, so not so important to have the comfort benefit of an invertor, and would take forever to pay back the additional cost. Should these turn out to be bad decisions I will report back.

[bangmai]

Just hunt around for prices, sometimes an a/c shop gives better service.

Just picked up a new model 12 Samsung at Big C for 10,900 installed. Once the real heat hits prices usually go up.

The Big C in Surin, has put up a new display of AC units, in the last 3 weeks, with some good prices. I brought a Carrier 18000 btu in Feb. for 17,000 baht delivered, that was marked down from 28,500. Over 8,000 baht cheaper than Home Pro or Power Buy. I also brought a Hatachi refrigerator, on sale for 2,000 baht less than the competitors.

that's a good deal. Some of the best appliance deals I have seen in Thailand were at Big C. Carrier brought refrigeration to LOS in 1936.....Often at 7-11, there will be an especially cold one blowing on me; I look up and it is frequently a Carrier.

[IMHO]

This is the most accurate AC sizing guide I've found, based on real world experience: http://www.rung-ruengair.com/new/InformationAir.html

The website may be accurate, but it is unreadable.

Take a look at the website using the Google Chrome browser and it will do a machine translation of the content from Thai into English. It's a statistical-based translation so hardly 100% accurate, but I find it's usually enough to get by.

Many thanks for all the reponses and in particular this reference - it's exactly what I was hoping to find. I now feel I understand a lot more about the entire process and how many BTU are required. I have decided to go with 12,000 BTU with inverter for the main bedroom, and 9,000 without inverter for the spare bedroom, on the grounds it will get much less use, so not so important to have the comfort benefit of an invertor, and would take forever to pay back the additional cost. Should these turn out to be bad decisions I will report back.

For the inverter unit that will be used more often, I would like to recommend the Daikin FTKM 12NV2S, which can be bought for under 22K, and is actually about 7.4/5 stars for energy efficiency. For about 3,500 Baht more you could get the 15K BTU version (FTKM 15NV2S) - which you can be absolutely sure will do the job, no matter how hot it gets.

[oneday]

We just bought 3 AC units for our new house.

Our large bedroom is the same size as your large bedroom...we got a 15BTU which may have been a little overkill, but the next smaller one I felt might have been a little undersized. The smaller bedroom is a little larger than your small one; for that one we got a 12BTU unit. Your alternate choice is to get a 9BTU and 12BTU, respectively. I just asked my wife and she said the 12BTU in the smaller bedroom was just fine...not humid.

I just feel that a 9BTU is undersized for only the smallest rooms. Also, depending on brand you can find 12BTU or 13BTU.

As far make...I had heard many good things about Daikin and so that is the manufacturer we settled on.

As far as inverter, yes...go for it. It saves money and puts much less stress on the motor by only slowing down or speeding up the motor as demand requires to maintain the temperature set, rather than turning it on and off. The only drawback is they are a bit more expensive, but from what I read you can easily make up the extra cost in about a year due to less electricity used.

You should also look at the type of refrigerate used if you care about the environment. I believe we got R32.

Maintenance is simple. Clean the filter about once every 6 months depending on how much dust is in the air. Clean the first time after 3 months of use and see what the filter looks like and then you have your gauge. Cleaning the filter is fairly quick and simple.

Lastly, about price. That's simple. First you pick the brand and model numbers you want and then shop around for those models only. Do not let someone try to talk you into something else or divert your attention. These are what you choose due to your research and so that is what you stick with for an Apple to Apple comparison. If makes shopping around very simple. If someone cannot get those models then you move on. Call the company of the manufacturer you choose in Thailand and get a list of places near you that sell those models.

The best price you get is who you buy from, but you need to also look at cost of installation and cost of the weather protection covers. Ours came with free installation and 5 meters of free weather covers. If we had lived in Bangkok we could have gotten better prices.

[lopburi3]

Clean filter every six months? Are you located in a hospital operating room? That filter should have regular cleaning in normal operation and the units itself pressure cleaned at least once or twice a year to get the dirt that gets through the filter.

As far as needing 15,000 btu for an 18sm bedroom - there must be a lot of gymnastic activity going on.

[femi fan]

I think the 12,000 and 9,000 estimates are correct. I have two rooms almost exactly the sizes you have, and these are the size of the split units I have in each of them. I am also in Chiang Mai. I purchased my units from Dragon Air on highway 1001, very near to Theppanya hospital. Their quoted price included the installation, and you can also purchase a one or two year cleaning/maintenance contract from them. I went with the Mitsubishi Slim Econo units. Be sure to bargain with them. When I informed them that I had a slightly lower estimate from another shop, they reduced their price by 1000 baht per unit.

Ah! I was hoping to find out about any air-con shops in chiang mai. Just could not think of any i have passed while driving around, but i've never been looking before. I know that hospital. Is this shop on the same side as the hospital or the other side of the road? I assume you mean the road leading up towards mae jo, i'm not very good at road numbers!

Some have said here, or elsewhere, that units should cost approximately 1 baht per BTU. Was that the kind of price you got? I've been quoted about 40% more than that at niyom panich.

What did you mean by 'split units'?

[jacko45k]

We had two units changed out from our old york brands, which are just plain horrible. Went with two Diakin inverters, and man am I happy. Before, with both units running the power consumption was over 6 kw per hour. Now, with both running it is just over 1 kw per hour. Amazing. And they are very quiet and regulate the temperature very very well. PM me if you want the name of the aircon company. But what ever you do, don't buy from homepro unless you like paying more.

I have 2 Daikin units too, inverter type and have been happy with them.

The initial cost was higher than other brands, but after replacing a Samsung that had given me grief recently and ultimately a compressor failure I decided to spend more. The Daikin service centre is near my house. The other old unit I have is Saijo Denkin, reversible...... and I think these are good units, but not well supported in my area.

[IMHO]

Some have said here, or elsewhere, that units should cost approximately 1 baht per BTU. Was that the kind of price you got? I've been quoted about 40% more than that at niyom panich.

Most of the big chain stores (Home Pro, Power Buy, Global House, Thai Watsadu etc etc) will always have at least some AC's on promotion that will be in the 1 Baht/BTU range (or less), and their prices are the same country-wide.

If the unit is only going to be used occasionally, these make perfect sense. If you'll be using the AC daily though, they might work out to be a false economy.

When shopping for either, always look at the bottom line number on the "Number 5 label" - that's the energy efficiency rating. Higher numbers are better. Poor performing units are in the <= 11.x range, average units are 12.x, good performing units in the 13-16 range, the best in the 17+ range. Running costs scale linearly with this number, and this number nearly always decreases as BTU increases (but not always - look carefully).

Outside of this, you should also look at the refrigerant used.

Some R22 units are still being sold, and should be avoided as it's already getting hard to find refill gas.

R410a units are fine.

R32 is the newest gas, has better cooling efficiency than R410a, and indicates the AC is an actual 2014-15 model.

Edited March 12, 2015 by IMHO

[Tywais]

Some R22 units are still being sold, and should be avoided as it's already getting hard to find refill gas.

R22 is being banned beginning Jan 2015 in most developed and developing countries including Thailand.

[bangmai]

They will still sell compressors that use it; just like they do in America, 3-4 years after the ban. They will not be charged, though. There have been some shortage scares of R-22, which is mostly BS, but has given technicians an extra opportunity to extort people. No one has been forced to do a retrofit, and very few have chosen to....different refrigerant requires different oil for one thing.

[IMHO]

Some R22 units are still being sold, and should be avoided as it's already getting hard to find refill gas.

R22 is being banned beginning Jan 2015 in most developed and developing countries including Thailand.

The rotal ban comes into efect Jan 1, 2018 in Thailand

[jcisco]

Are you able to just purchase one condenser unit and two head units with the low btu total. Also living in Singapore for a long time I became a fan of the quarterly maintenance regime required for aircons, a full clean of the filters and heat exchangers and a flush of the condensation line. It won't cost you much for the service and saves having to clean it yourself or having water in your home with mold soon to follow. They also check the gas at each cleaning visit.

[sandyf]

My main bedroom is 20 sq m and has 2 windows 4ft x 3ft. It is a bungalow and the bedroom is on the SE corner, the walls are cavity wall construction so quite well insulated. Unfortunately the same cannot be said for the roof.

When I built the house I ran out of money so we just lived in the bedroom initially. I had a 13k BTU Panasonic fitted but it just could not cope in the height of the hot season, set at 27 it just never switched off.

When my pension kicked in, the first thing I did was change the bedroom AC. I think a 15K BTU unit would have been ok but just couldn't find one that size so I settled for a 18K LG model. I moved the 13K unit into the small bedroom, bit of an overkill as that is only 12 sq m., and I also put another 18K in the lounge. The lounge is about 36 sq m so that is only used when I am watching TV. The LG in the bedroom works ok but not to be recommended as they are a bit basic and noisy.

When I can afford it I will get a better unit for the bedroom and move the LG 18K into the other end of the lounge.

AC is subject to so many variables it can be extremely difficult to get it right. Particularly when many cannot agree on what is right.

Good luck.

[IMHO]

Are you able to just purchase one condenser unit and two head units with the low btu total. Also living in Singapore for a long time I became a fan of the quarterly maintenance regime required for aircons, a full clean of the filters and heat exchangers and a flush of the condensation line. It won't cost you much for the service and saves having to clean it yourself or having water in your home with mold soon to follow. They also check the gas at each cleaning visit.

Yes, you can purchase big compressors that are able to support multiple indoor units. They're very expensive - much more than just the sum total of single systems - and they're very, very energy inefficient compared to what the same money or less could buy. The only real use-case for such systems is condo's where you just don't have the balcony space for a bunch of compressors.

[masuk]

We rented a house in QLD a couple of years back. it was like a sauna!

I got onto a wholesaler and had some 150mm insulation supplied (the minimum required for the tropics).

Installed this and it made a huge difference. Daytime room temp went from 45C down to low 30s.

A pity the land lady didn't pay us for this, 6 months later.

[Beardog]

We have 2 of the same size rooms with 9000's fitted they work fine. we only timer 2-3 hours in the night & then it goes off & we keep the windows open with a drape so some cold air escapes I am sure. We keep it at 25 degrees & like Tywais was saying the only time it will be different is in the heart of hot season & it is still no problem we just let it run for all night. The other room is my internet room & I only run it when it gets too hot. We have sunlight fans in the rooms so it gets plenty of circulation & built the house right & made sure nothing is facing direct west.And we also have trees we grew to shade all the walls with basic 7.5 cm super block. Single story so we don't have the upstairs to get hot. But really Unless you need an icebox the 9000's will do the job & if you do get tempted a 12000 at most. But it all depends on the western exposure Did they put in the solar wrap under the roof. If your ceiling is only 2.5 meters height it will be a tad warmer. Our ceilings are 3.2 meters to avoid head swelter. If it is a newer house it most likely is 3 meters. That is now pretty much standard unless your a hobbit. I run the air in the internet room for 2 hours every month regardless of the temperature get rid of humidity & keep the compressor working. air cons are pretty cheap on the newer ones an inverter if your not using it a lot you will be long dead before you see any savings. If you use it a lot by the time you move or are sick of it you may break even That is based on people I know in Pattaya. the ones that use a lot OK the ones that use a little it is just a waste of money. We have regular Daikins & they work well the remote is a little weird but a great air con. My favorite is Toshiba Because it does the same as is quieter at high speeds the Diakin noisier if you crank up the fan, they give you a longer warranty & any idiot can use the remote.Don't go over you are just creating more problems. Bigger not better in Ac's

[ywamer]

In my experience, Siam TV is the best place to buy air-conditioners in Chiang Mai. They all come with free installation, however, the install waiting list might be few weeks long now that you've waited to the hot season.

Also, I 100% agree that oversizing is bad. It leads to humid-feeling rooms and greater temp variation... which means you feel cool, then a bit too warm, then cool, them warm... especially when under a blanket or thick comforter.

It appears to be that every air-con salesman is out to upsize customers to buy larger units. They will ALWAYS ask you how big your room is and recommend a higher BTU device. So underestimate your BTU usage by a bit to keep your room cool and maximize efficiency.

Grossly underestimating BTU needs is crazy - like a friend of mine who wanted to put a 9k BTU in his large living room. The installer refused to do it, and recommended a 30k+. In the end, my friend came around to his senses and bought a 24k BTU. A good choice for his room, neither too small nor quite what the air con shop recommended.

Oversizing is a bad idea for a variety of reasons. I will just post a few of the many links that explain it. Due to short cycling, humidity removal is reduced, energy costs go up, uneven cooling - that is from hot to cold to hot. Here is a quote from one of them.

There are three reasons:

First is that an air conditioner is most efficient the longer it runs. If it is too big, it will run for a couple of minutes at a shot, whereas, if it is the right size, it will run much longer – on the hottest afternoons of the year, it should run all the time. This delivers the cold air at the lowest cost and more evenly.

The second is that the air conditioner is also a dehumidifier. Here on the West Coast we spend about 20% of our air conditioning money on taking moisture out of the air. If the unit is too big and spends more time off than on, the coils won’t get cold enough for a long enough period of time to condense enough moisture to be effective in removing moisture from the air.

The third problem with oversizing the air conditioner is that if you buy too big a unit, you are simply wasting money. A properly sized unit has a fudge factor built-in, so that once a proper heat loss/gain calculation has been done, buying a larger unit than called for is unnecessary.

http://www.energyvanguard.com/blog-building-science-HERS-BPI/bid/55157/Why-an-Oversized-Air-Conditioner-Is-a-Bad-Idea

http://buildingdoctors.com/home-cooling-systems

http://www.weeks-service.com/oversizedairconditioner.htm

http://www.diynetwork.com/electrical/keeping-it-cool-how-big-should-an-ac-unit-be/index.html

[oldmanofhoy]

Thanks for that ywamer,it neatly sums up just about everything I had gleaned from the more cogent of the other posts and I'm happy (so far) that we've made the right decision. We got lucky with the installation - it was today! I don't get back to Chiangmai until early April, but will report back on how it appears to be working at keeping the rooms cool and non-humid in due course.

[billphillips]

Just a note on the humidity as I can see some confusion in various posts.

Warm air can absorb moisture easily, if that same warm and moisture laden air is cooled, it will deposit the moisture onto any cold surface. Hopefully, the matrix in your room cooler but if not ... any cold glass or bottle of water will do. Cool air cannot retain water in the same quantities as warm air. Heavily moisture laden air takes longer to cool than low moisture content air. The idea of the aircon cooling the air but still being high in humidity is not a reality.

A simple check of placing a cold bottle of water in the uncooled and then the cooled room (with aircon running for a reasonable amount of time) will show that this is correct. For those with more of an understanding of humidity will already know that condensation only starts to form on a bottle of chilled water after its removed from the fridge. It's doesn't have condensation present inside the fridge.

[oldmanofhoy]

Nearly 5 months on, I've installed Daikin air conditioners from Siam TV (with inverters) in 3 of the 4 bedrooms, and all is well with these. I have held off installing 2 x 18,000 BTU units in the living room as well as another 9,000 BTU A/C in the final bedroom, thinking I would get a better price if I waited until the rainy season.

Today Siam TV are still quoting the same price as they were in March B.29,900 for the 18,000 BTU units and B19,900 for the 9,000 BTU unit, but are offering Seven-Eleven vouchers amounting to about 3.5% discount. Is this the best deal we will get (I want ot keep it with Siam TV, so all the routine maintenance can be done at the same time by the same engineer) or would it be worth hanging on a bit longer for a more attractive deal?

[sfokevin]

^^^ You might check out promotional pricing at the new PowerBuy that just opened on the Moat...

And I got a great discount when I bought my Samsung's at Robinson's in Airport Plaza - They gave me free upgrade of pipe covering too

Can you tell us a bit more on how the 9K BTU inverter are working out?... 9K seems a bit small?... Do they do a good job of cooling?