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Scout
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The Home Air-Conditioner Thread

Post by Scout »

I’ve searched the forum but can’t find answers to these questions so thought I’d start a new thread. I have 6 air-conditioner units installed in various rooms of my house. Some rooms are small, one is quite large with lots of windows. I purchased the house about a year and a half ago. A couple of these air-conditioners are about 12 years old, a few are around 5 – 6 years old and 1 is only a year old. I have an air-conditioner service company (Mr. Bird) that I believe to be very capable and fair, which I hire to provide annual cleaning and servicing, as well as to fix problems as they arise.

Three of my air-conditioners apparently have coolant leaks and must be recharged every few months, cost around 800 baht each time. Mr Bird informed me that because these units have aluminum heat exchangers, they cannot be repaired. Mr Bird wants to sell me new air-conditioner units, or he would be happy to return every few months to recharge the leaking units. I’ve googled a lot of information on aluminum versus copper air-conditioner heat exchangers and it does appear that repairing aluminum is much more difficult than repairing copper, but not impossible. It also appears that aluminum has become the material of choice for many air-conditioner manufacturers, for a variety of reasons. Because my current units still work fine when the coolant is recharged, I’m reluctant to throw them out and buy new. I do not know if the leak is in the larger exterior exchanger, the smaller one inside the house or possibly in the piping that connects the two. Does anyone have experience here in Hua Hin with repairing aluminum air-conditioner heat exchangers ? Can anyone recommend a repair service that is capable of finding and repairing leaks in aluminum air-conditioners ?

Also, due to the age of my air-conditioners, I’m wondering if it would be cost efficient to simply replace them with brand new, state-of-the-art technology. I have friends that recently bought a new air-conditioner that has “inverter” technology, they swear this new technology uses so much less electricity that it will pay for itself in a short period of time. I am not sure what “inverter” technology is or if it would be much more efficient than the older units I currently have. Does anyone have experience with or information on the efficiency of the brand new “inverter” technology air-conditioners, compared to my older units ?

Regarding the debate between using aluminum versus copper heat exchangers, if I do decide to replace my older units, does anyone have information and an opinion on which way I should go ?

If I do decide to buy new units, an obvious decision point will be what size (BTU cooling capacity) units to buy. There seem to be 2 schools of thought on this. One school of thought is to buy the smallest size unit calculated to be sufficient for the size of the room it will be cooling. The thinking seems to be that these smaller units will use less electricity while providing adequate cooling capacity. Another school of thought is to buy a unit with a much larger BTU cooling rating than absolutely required. The thinking seems to be that when initially turned on, the unit will cool the room much quicker than a smaller BTU rated unit, and after the room reaches the set temperature the unit will cycle the compressor on and off, sort of like coasting downhill (and using minimal electricity) to maintain the set temperature. I’m aware that larger BTU rated air-conditioners have a larger initial purchase price, but I’m wondering if long term they would be more efficient and ultimately provide cost savings due to reduced usage of electricity. Does anyone have thoughts or experience with this decision point ?

Thanks in advance for your thoughts and recommendations.
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Re: The Home Air-Conditioner Thread

Post by PeteC »

Addressing the inverter issue, I can't say I've seen electricity savings over the last 9 years with Daikin units that offsets the extra 20,000 baht price tag for a large unit. Perhaps I'll recover that extra cost in full by the time I need to buy new units? :shock: :laugh:

Having inverter and non-inverter Daikins, I can say those with the inverters have more things go wrong, and need full professional cleaning more often than regular units. On the other hand, they are much quieter for night time use than non-inverter types.

My though is that during the past 9-10 years inverter technology has improved and the problems I experience have been addressed and eliminated. One can hope. Pete :cheers:
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Re: The Home Air-Conditioner Thread

Post by Nereus »

Three of my air-conditioners apparently have coolant leaks and must be recharged every few months, cost around 800 baht each time. Mr Bird informed me that because these units have aluminum heat exchangers, they cannot be repaired.
Has he shown you just where the leaks are? Even units with aluminium coils, either in the evaporator or the condenser, usually have brass fittings to connect to the external piping, which is normally copper on domestic split units. The connection is made with a flare type compression fitting, which can leak if not made off correctly. The usual cause of leaks in the actual aluminium tubing is more often than not caused by ham fisted cleaning, as it does not corrode or otherwise deteriorate.
He is correct about repairing aluminium tubing. It can be done but requires the correct welding equipment. If it is not new then it is almost impossible to get it clean enough to weld, and the build-up of oil internally will continue to contaminate any attempt at welding. There is epoxy type fillers that may work for a limited time, but are not guaranteed.
I have friends that recently bought a new air-conditioner that has “inverter” technology, they swear this new technology uses so much less electricity that it will pay for itself in a short period of time. I am not sure what “inverter” technology is or if it would be much more efficient than the older units I currently have.
Yes, modern current inverter types are much more efficient, albeit a bit more expensive. The basically work by controlling the speed of the compressor. There is no big inrush of current when they start up, and as the load reduces they slow down to just enough speed to maintain the set temperature, rather than stop and start over and over.
Regarding the debate between using aluminum versus copper heat exchangers, if I do decide to replace my older units, does anyone have information and an opinion on which way I should go ?
You may find that you have no say in the matter. Ask a supplier of air cons here which material is in the unit and I would suggest that in 99 times out of 100 you will get a blank look.
If I do decide to buy new units, an obvious decision point will be what size (BTU cooling capacity) units to buy. There seem to be 2 schools of thought on this.
There are many factors that need to be considered when sizing a unit. What material is the building constructed from, is there any insulation, is it single or double storey, what is the aspect in regard to the sun, what and where are the windows located, etc., etc. And yes, it is better to err on the side of a bit bigger. There are many charts on the Internet that suggest what to consider, and how to calculate the size.

In my experience here I have yet to find ANY local air conditioning people that have any training in what is involved. Each and every one of them use a method of charging that is completely wrong, and results in the incorrect amount of gas in the system. Not one of them has, never minds knows, what a “recovery unit” is. In most overseas countries they would not be allowed to operate, and in many counties incur a huge fine for pollution.
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Re: The Home Air-Conditioner Thread

Post by Bristolian »

Nereus wrote:He is correct about repairing aluminium tubing. It can be done but requires the correct welding equipment. If it is not new then it is almost impossible to get it clean enough to weld, and the build-up of oil internally will continue to contaminate any attempt at welding.
Good post sir
Agreed 101%.

It is possible to not only weld aluminium but also to braze aluminium using low temperature specialist and expensive rods ( I have not found them in Thailand) but the cleanliness is the same. Super clean and using stainless steel brushes to fully expose the clean surfaces ready for a weld or bond. For a thin wall tube you can forget both processes.
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Re: The Home Air-Conditioner Thread

Post by brianks »

A friend of mine replaced a 15 year old and broken AC unit with a new Inverter unit for his bedroom and his electricity bill went down over 2,000 baht/month.
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Re: The Home Air-Conditioner Thread

Post by wpcoe »

The trick with getting an inverter air con is getting the appropriate size, which is a question brought up in the opening post. Ideally you have an inverter unit sized so that the room is cooled down quickly and that then the outdoor unit (compressor) slows down to consume less electricity while maintaining the desired temperature while the indoor unit (evaporator) fan also slows down to a low speed.

If a unit is too large, even an inverter can shut off the compressor completely, meaning no cooling/dehumidifying is being done. If a unit is too small, an inverter never gets the opportunity to slow down the compressor or the interior unit's fan and simply runs full tilt like a non-inverter and there is no operational cost saving.

The operational cost savings over a non-inverter unit is greatest when the compressor and the evaporator's fan can competently handle the cooling load at a slow speed without shutting off.

Between the increased efficiency of newer technology and the advantages of a properly sized inverter, there can indeed be significant operational savings over a 10+ year old unit.
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Re: The Home Air-Conditioner Thread

Post by Nereus »

The trick with getting an inverter air con is getting the appropriate size,
Exactly the same parameters apply to calculating the BTU requirement, regardless of whether or not it is an inverter type. An inverter type simply converts the power being used in a much more efficient way.

I am no longer hands on with this stuff, or the latest advances in inverter techknowledgey, but from past experience I have never seen an inverter type that has a problem with stopping the compressor. One big advantage of an inverter type is the ability to maintain the set temperature in a virtually flat line, as against a standard type that both overshoots and undershoots the set point up to 3 or 4 degrees. It is the continual stopping and starting of a non-inverter type that wastes power with its cycling, continually chasing the set point.

Like most things, you have to weigh up both advantages and otherwise when considering which unit is best suited to your intended use. If you only turn it on for a couple of hours at night to cool down a room, and then switch it off, you are probably better of with just a standard type. If you want to run it for 8 or 10 hours to maintain a room at a set comfortable temperature, then the extra initial cost of an inverter type will probably be justified.
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Post by hhinner »

^^Nereus, I love the way you merged "tech" and "knowledge". Be very disappointed if it wasn't deliberate. :)
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Post by Nereus »

hhinner wrote:^^Nereus, I love the way you merged "tech" and "knowledge". Be very disappointed if it wasn't deliberate. :)
8) :wink:
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Re: The Home Air-Conditioner Thread

Post by Melbourne John »

Great read/education guys. Good questions, terrific answers.

A new boy can't help but appreciate the quality of the expat knowledge stock in this thread.

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Re: The Home Air-Conditioner Thread

Post by huahin4ever »

I just replaced my AC in my bedroom with a new inverter type. Will be interesting to see how much our electricity bill is reduced. Besides the obvious savings on electricity consumption, my first positive experience with the new unit is that it runs much more efficiently and OH so quiet (has special quiet mode and sleep mode) :-D
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Re: The Home Air-Conditioner Thread

Post by AJBangkok »

I am also looking to install new air conditioning in a house that's almost completele. I am looking to install Daikin static duct inverter units, 4x 48000 BTU, 2x 36,000 BTU and 1x 24,000 BTU. My issue is that the shop in Hua Hin has marked up every unit by 15,000 baht. I have found 2 Bangkok companies and one Phuket company that offer the aircon units at prices 14-16k lower, however the Bangkok companies have no interest in installing in Hua Hin.

When I questioned the quote I was told that it's installation charge. Just so there is no confusion the quote also includes around 200k for ducting, piping and other materials to install the units. I figure the material prices are also marked up 50 - 100%

I want the duct units as they look better than units hanging off the wall and I don't mind paying a fair or even high price to get them put in but he is asking crazy prices. I doubt if Boonthawan sells these kind of air cons but I would happily pay them as while they are higher than normal price they aren't thieving from me.
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Re: The Home Air-Conditioner Thread

Post by Nereus »

^^^^^^^^^^
That is some mighty air cons! Are you sure about the numbers? 288,000 BTU total is 24 tons of cooling. :shock:

Have you considered Cassette type of units? These fit flush into the ceiling and are not obtrusive. They are also available with multiple room units, up to 4, that run from one condensing unit. I hope that you also have a 3 phase electric supply.
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Re: The Home Air-Conditioner Thread

Post by AJBangkok »

Nereus wrote:^^^^^^^^^^
That is some mighty air cons! Are you sure about the numbers? 288,000 BTU total is 24 tons of cooling. :shock:

Have you considered Cassette type of units? These fit flush into the ceiling and are not obtrusive. They are also available with multiple room units, up to 4, that run from one condensing unit. I hope that you also have a 3 phase electric supply.
I have considered the cassette type and they won't look good where I want them placed in the living and dining room and in 2 of the bedrooms they would pretty much have to be positioned over the bed which wouldn't work. I figured if I needed 4 duct type I may as well get them all duct type. I do have 3 phase electricity.

My issue is really the cost without installing and piping/materials should be around 440k for 7units. He wants an additional 375k for installation and associated materials do so the total fully installed would be 815k.

From what I have found out talking to other vendors in Bangkok the price should probably be in a range of 570 -640k depending on the length of the wiring runs etc
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Re: The Home Air-Conditioner Thread

Post by Hnlwayne »

There are several people on this thread that obviously know a lot more about air conditioning than I do but I can comment on running costs. In the past two years I replaced four ten year old Carrier split systems of various sizes with Panasonic inverter types. I got the deluxe ones that boast 60% energy savings compared to 50% for the standard inverter. This is supposed to be comparing new inverter vs. new non inverter. I am sure I am saving over 50% keeping mind I had old non inverters.

My understanding is that "inverters" change your 220volt ac to dc. With dc you can slow the motor down when you need less cooling power. It is also better for the compressor because starting and stopping is hard on them.

Keep in mind if you are going for Arctic conditions ( 23 Celsius) or less in a hot climate the inverter won't save you much because the compressor will be going full on all the time. We set ours at 26 or 27 and our savings will pay them off in less than two years. They would pay for themselves even sooner but two of them are not used much.
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