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Buying An Energy-Efficient Air Conditioner


Mekong Bob

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My bedroom is 21.6 sq/m, it's north-facing, the ceilings are 2.65m high, they are hung gypsum ceiling tiles.

Would a 12,000 BTU Mitsubishi aircon unit be adequate? I plan on using a single layer of 3" insulation and I'm also going to close up the gaps in the windows from the shoddy build of the house & the movement since the house was built.

We like to sleep in pretty frosty conditions so would that be adequate?

12,000 BTU is going to cost B21,000, an 18,000 BTU is going to cost almost B30,000.

Any advice?

we had a room in almost the same size, our ac was not good anymore and we asked the owner to put in a new ac. He wanted to put in a 18000 BTU Panasonic Split AC. Since I like it cold as well 19-20 degrees but I still wanted it quiet I calculated and came to the result that a 12000 BTU should do.

I have little electronic thermometers with hydrometers in each room. Evenso they are not 100% accurate they are close to. So I can see the actual temperature in all rooms quite precise and are not dependent on the Aircon temperature setting which may be wrong.

Look here: http://www.airmercha...m/whatsize.html, even you use no insulation, have big windows and doors, facing North I calculated around 3.3 kW, and checking kW to BTU converter here: http://www.rapidtabl...r/kW_to_BTU.htm that converts to about 11,260 BTU. So you should be ok with 12,000 BTU.

I would recommend to check on the Panasonic Units, they are really good, very quiet, have ION function (cleaning the air) and are very cost effective (cheap in consumption)

Edited by yannic
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My bedroom is 21.6 sq/m, it's north-facing, the ceilings are 2.65m high, they are hung gypsum ceiling tiles.

Would a 12,000 BTU Mitsubishi aircon unit be adequate? I plan on using a single layer of 3" insulation and I'm also going to close up the gaps in the windows from the shoddy build of the house & the movement since the house was built.

We like to sleep in pretty frosty conditions so would that be adequate?

12,000 BTU is going to cost B21,000, an 18,000 BTU is going to cost almost B30,000.

Any advice?

we had a room in almost the same size, our ac was not good anymore and we asked the owner to put in a new ac. He wanted to put in a 18000 BTU Panasonic Split AC. Since I like it cold as well 19-20 degrees but I still wanted it quiet I calculated and came to the result that a 12000 BTU should do.

I have little electronic thermometers with hydrometers in each room. Evenso they are not 100% accurate they are close to. So I can see the actual temperature in all rooms quite precise and are not dependent on the Aircon temperature setting which may be wrong.

Look here: http://www.airmercha...m/whatsize.html, even you use no insulation, have big windows and doors, facing North I calculated around 3.3 kW, and checking kW to BTU converter here: http://www.rapidtabl...r/kW_to_BTU.htm that converts to about 11,260 BTU. So you should be ok with 12,000 BTU.

I would recommend to check on the Panasonic Units, they are really good, very quiet, have ION function (cleaning the air) and are very cost effective (cheap in consumption)

We've had really bad experiences with aircon over the years, the only time we've had a say in what aircon we had - in the house we were renting at that time - we chose Mitsubishi and it was excellent for the 3 years we stayed in that house, never made a noise, was always fast to cool & bills were reasonable(we didn't get dry throats either!).

My wife has had the same experience with Mitsu in her life before we got together so I'm very reluctant to buy anything other than what we've had personal experience of.

Only occasionally do I have enough money, at any given time, to spend on something as large an investment as aircon and I don't want to end up disappointed again, I can appreciate everybody’s experiences are different but I just can't risk it any more, for the last 3 years we've had noisy aircon and it has driven us mad! Now I have the chance to change that.

Anyhow, back to the BTU. My wife is insisting on 18k. Based on the sq/m of our room it would seem 12k BTU is adequate but again, if we get the 12k BTU and it's not good enough for what we want, I'll be right up shit creek again, pumping it out and wearing it down :(

There would be no turning back once the unit is installed.

Will an 18k BTU unit last longer than a 12k unit under consistent use of 21c?

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Look here: http://www.airmercha...m/whatsize.html, even you use no insulation, have big windows and doors, facing North I calculated around 3.3 kW, and checking kW to BTU converter here: http://www.rapidtabl...r/kW_to_BTU.htm that converts to about 11,260 BTU. So you should be ok with 12,000 BTU.

I'm not sure it's recommended to use these kinds of calculators unless they're specific to the country, this 'whatsize' calculator for example, with the paramaters of my house it would seem a south facing house would need less kW(3.06kW) than a north facing house with the same parameters(3.08kW) and surely that's not right...

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my 18.000 btu samsung aircon if used for 8 hours a night at around 25 dont like it to cold costs me about a 1000 bhat a month bargin

Holy crap, that's near double our total power bill!

Yes but not everybody uses kerosine lamps, cold showers and and a hand fan.

I actually use 2 of those 3, and im still at 1500 lol. MAybe he lives in Issan?

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My bedroom is 21.6 sq/m, it's north-facing, the ceilings are 2.65m high, they are hung gypsum ceiling tiles.

Would a 12,000 BTU Mitsubishi aircon unit be adequate? I plan on using a single layer of 3" insulation and I'm also going to close up the gaps in the windows from the shoddy build of the house & the movement since the house was built.

We like to sleep in pretty frosty conditions so would that be adequate?

12,000 BTU is going to cost B21,000, an 18,000 BTU is going to cost almost B30,000.

Any advice?

Whatever you do, things are going to make a BIG change for the worse in the months around June. People pick units in winter and are very surprised when the sun begins to rise and set more north after March. We are "below" the tropic of cancer too, so we don't get that north facing shade aspect that many in say the US get year round. In short, at the hottest part of the year the sun will be blaring into your place. Plan for it, and buy accordingly. Don't base anything on the now (ie Feb).

Edited by isawasnake
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My bedroom is 21.6 sq/m, it's north-facing, the ceilings are 2.65m high, they are hung gypsum ceiling tiles.

Would a 12,000 BTU Mitsubishi aircon unit be adequate? I plan on using a single layer of 3" insulation and I'm also going to close up the gaps in the windows from the shoddy build of the house & the movement since the house was built.

We like to sleep in pretty frosty conditions so would that be adequate?

12,000 BTU is going to cost B21,000, an 18,000 BTU is going to cost almost B30,000.

Any advice?

Whatever you do, things are going to make a BIG change for the worse in the months around June. People pick units in winter and are very surprised when the sun begins to rise and set more north after March. We are "below" the tropic of cancer too, so we don't get that north facing shade aspect that many in say the US get year round. In short, at the hottest part of the year the sun will be blaring into your place. Plan for it, and buy accordingly. Don't base anything on the now (ie Feb).

Good advice, and something I've thought of in the past. I think 18k BTU is the winner...

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The shitty Singer unit we have now is mostly on 21c, and sometimes that's not cold enough

21ºC is not "very very cold" but it would be helpful to answer your initial question if you lift the secret "capacity and age" of the "shitty Singer unit". precise answer please! not something like "the unit is 81cm long and it looks very very old".

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The shitty Singer unit we have now is mostly on 21c, and sometimes that's not cold enough

21ºC is not "very very cold" but it would be helpful to answer your initial question if you lift the secret "capacity and age" of the "shitty Singer unit". precise answer please! not something like "the unit is 81cm long and it looks very very old".

Naam, in our ever-so-humble opinions, 21c, after a few hours, is pretty dam_n cold, you may not think so, but we can actually feel it.

Revealing my secrets now Naam - The SHITTY SINGER UNIT is 18k BTU & is 2 years old.

A hotel in Phnom Penh I once stayed in had an identical fan unit to ours, strangely though, it was a Chinese-labelled unit, insides were identical too. This made me realise that we had bought from Singer, but it wasn't Singers product, it was a random low-quality Chinese brand. I have come to realise that we couldn't neccessarily trust the BTU of the unit too.

After about 6 months of use it started to leak, and I don't mean just the odd drip or spit that you might get from time-to-time on other units, I mean 2 full 10 litre bowls of water each 8-hour night, this in turn ruined our curtains which weren't cheap, see pic, you can see the rust-coloured markings on the curtains below each side of the vents.

post-78826-0-91634500-1360720529_thumb.j

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After about 6 months of use it started to leak, and I don't mean just the odd drip or spit that you might get from time-to-time on other units, I mean 2 full 10 litre bowls of water each 8-hour night, this in turn ruined our curtains which weren't cheap, see pic, you can see the rust-coloured markings on the curtains below each side of the vents.

any unit will drip and spit if its drain pipe for condense water is blocked.

Naam, in our ever-so-humble opinions, 21c, after a few hours, is pretty dam_n cold, you may not think so, but we can actually feel it.

i wholeheartedly agree even though i am cooling down our bedroom to 18ºC before i go to bed. but then the aircon is switched off and the room warms up slowly in line with the temperature my body likes.

summary: to be on the safe side bite the bullet and go for a 24,000btu/h unit if you like 20 or 21º even during the hottest season. the difference between an 18k and a 24k is (depending on the brand) only a few thousand Baht.

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After about 6 months of use it started to leak, and I don't mean just the odd drip or spit that you might get from time-to-time on other units, I mean 2 full 10 litre bowls of water each 8-hour night, this in turn ruined our curtains which weren't cheap, see pic, you can see the rust-coloured markings on the curtains below each side of the vents.

any unit will drip and spit if its drain pipe for condense water is blocked.

Naam, in our ever-so-humble opinions, 21c, after a few hours, is pretty dam_n cold, you may not think so, but we can actually feel it.

i wholeheartedly agree even though i am cooling down our bedroom to 18ºC before i go to bed. but then the aircon is switched off and the room warms up slowly in line with the temperature my body likes.

summary: to be on the safe side bite the bullet and go for a 24,000btu/h unit if you like 20 or 21º even during the hottest season. the difference between an 18k and a 24k is (depending on the brand) only a few thousand Baht.

I'm a little shocked to read you recommending 24k BTU, the Mitsu unit I have my eye on is pretty large already, I'll have a look in the aircon shop today and see if the size/price is much larger for the 24k BTU, to be frank, B30,000 is my limit, so unless either the shop can come down to that or I go with a lesser brand(NEVER AGAIN!) I'll have to stick with an 18k BTU unit.

Thanks for your recommendation Naam!

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After about 6 months of use it started to leak, and I don't mean just the odd drip or spit that you might get from time-to-time on other units, I mean 2 full 10 litre bowls of water each 8-hour night, this in turn ruined our curtains which weren't cheap, see pic, you can see the rust-coloured markings on the curtains below each side of the vents.

any unit will drip and spit if its drain pipe for condense water is blocked.

That's exactly what happened, and I believe it's because of the drainage pipes being too small and the uneven installation of the fan unit - AVOID SINGER AIRCON(& THEIR INSTALLATION 'TECHNICIANS')

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Good advice, and something I've thought of in the past. I think 18k BTU is the winner...

you don't need the 18k BTU unit. It is to overpowered for your room. Also the 18k unit is much louder then the 12k unit and the electricity consumption is also much higher. The 12k unit cooled our room down quickly which was a bit bigger then yours.

But of course you can buy whatever you feel you need.

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I would go for the bigger unit. It does not need to run on full power all the time. For brand, look at service available.

We have Daikin and I would not recommend it. It is an impossibility to find replacement remotes. And if they cost much more than other brands.

Sent from my GT-I9100 using Thaivisa Connect Thailand mobile app

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Good advice, and something I've thought of in the past. I think 18k BTU is the winner...

you don't need the 18k BTU unit. It is to overpowered for your room. Also the 18k unit is much louder then the 12k unit and the electricity consumption is also much higher. The 12k unit cooled our room down quickly which was a bit bigger then yours.

But of course you can buy whatever you feel you need.

My wife is adamant that the unit we have now is 18k BTU, it was quiet for the first couple of months, then the (low) quality kicked in and it started getting louder and louder.

In my previous house, one of the units was a 24k BTU Mitsu, it was silent for the 3 years we stayed in that house, the compressor was LARGE too, possibly about 120cm tall & wide so I don't see the argument that 18k BTU will make more noise than another size, I think it depends on quality to a large degree...

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summary: to be on the safe side bite the bullet and go for a 24,000btu/h unit if you like 20 or 21º even during the hottest season. the difference between an 18k and a 24k is (depending on the brand) only a few thousand Baht.

Naam, this is the same "als wuerdest Du mit Kanonen auf Spatzen schiessen" (to take a sledgehammer to crack a nut). And with this recommendation I can see how much Thai you are already. The Thais do exactly the same. For many of the new Condominiums they put in every room much to big aircons. And in every room they use plenty of the expensive 50 Watts halogens, as if electricity cost wouldn't matter at all.

In our new condo they have an aircon which is 3 times to big for the room. It is loud as hell during the night. Of course it cools down the 50 sqm masterbedroom to 18 degrees celcius in no time, but the electricity consumption and the noise is really not good.

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summary: to be on the safe side bite the bullet and go for a 24,000btu/h unit if you like 20 or 21 even during the hottest season. the difference between an 18k and a 24k is (depending on the brand) only a few thousand Baht.

Naam, this is the same "als wuerdest Du mit Kanonen auf Spatzen schiessen" (to take a sledgehammer to crack a nut). And with this recommendation I can see how much Thai you are already. The Thais do exactly the same. For many of the new Condominiums they put in every room much to big aircons. And in every room they use plenty of the expensive 50 Watts halogens, as if electricity cost wouldn't matter at all.

In our new condo they have an aircon which is 3 times to big for the room. It is loud as hell during the night. Of course it cools down the 50 sqm masterbedroom to 18 degrees celcius in no time, but the electricity consumption and the noise is really not good.

You're right in some cases, for the people who have more money than sense, but I would imagine that most Thai people simply get what they can afford.

I have stood nearby large compressors, during operation, and they have been quieter than mine!

You say that new apartments install the wrong sized aircon, surely they would be aware of the money they were wasting, they seem to do a pretty good job of saving money on EVERYTHING ELSE! :D

Edited by MaiDong
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Hi,

I replaced my 10 year old aircon in my bedroom about 9 months ago. I did the measurements to calculate the BTU required to properly cool the room and found out that my old aircon was way too powerful. My old aircon was a Carrier 4.95 kW, I think it produced around 16900 BTU. The new aircon I bought is a Mitsubishi Inverter MSZ/MUZ-SGH13VA producing 12,200 BTU, and it operates at the low fan mode 95% of the time cooling the room to 26 degrees C.

I actually wanted to go lower than 12,200 BTU, but the sales person "advised" against it, citing that if the unit is too small it will void the warrantee and the installer may not want to install it at our condo. Later found out that the sales was lying to me. The new unit did reduce my electricity costs by around 30%, but I know the smaller unit can save me even more.

Do take into consideration on when you will use the aircon and search for "calculate air conditioner size" to come up with websites to help you calculate the cooling capacity needed for your room.

The reason why I wanted to go smaller was because I only used it at nights and on rare occasions in the day. Besides, if I really wanted things cooled I could turn on all the aircons in the condo to quickly cool the rooms down. So calculate your room properly.

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You say that new apartments install the wrong sized aircon, surely they would be aware of the money they were wasting, they seem to do a pretty good job of saving money on EVERYTHING ELSE! biggrin.png
yeah I am talking about the bigger size condominiums, not the small study type rooms, the ones 200 sqm and up they really put in over sized aircons and halogens like crazy. I asked our Condo Manager and she explained that the customers demanded fast cooling in the rooms (not sure if this is so accurate) but that's the reason they put in well oversized aircons into the rooms.The most important thing is to buy an inverter type split aircon, like the one mentioned by indothai it will cool down quickly. it can be on quiet mode and it saves energy if it is not oversized or undersized. Therefore I stay with my recommendation to use a 12k BTU unit.In our condo in the Philippines we had a unit like this:http://www.panasonic.../deluxeinvertorIt was very effective, quiet and cost efficient

By the way there is a good post from a friend of mine about aircondition in his house in Iloilo. He describes it in great detail. Have a look here:

http://myphilippinelife.com/our-philippine-house-project-air-conditioning/

Edited by yannic
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summary: to be on the safe side bite the bullet and go for a 24,000btu/h unit if you like 20 or 21º even during the hottest season. the difference between an 18k and a 24k is (depending on the brand) only a few thousand Baht.

Naam, this is the same "als wuerdest Du mit Kanonen auf Spatzen schiessen" (to take a sledgehammer to crack a nut). And with this recommendation I can see how much Thai you are already. The Thais do exactly the same. For many of the new Condominiums they put in every room much to big aircons. And in every room they use plenty of the expensive 50 Watts halogens, as if electricity cost wouldn't matter at all.

In our new condo they have an aircon which is 3 times to big for the room. It is loud as hell during the night. Of course it cools down the 50 sqm masterbedroom to 18 degrees celcius in no time, but the electricity consumption and the noise is really not good.

-we have a 24k and a 12k in our bedroom to reach 18ºC within 2 hours. the two 12k we had before couldn't do the job.

-what you forgot is that "Maidong" is demanding 20-21ºC which he can't achieve with a 12k during the hottest season.

And with this recommendation I can see how much Thai you are already. In our new condo they have an aircon which is 3 times to big for the room. It is loud as hell during the night. Of course it cools down the 50 sqm masterbedroom to 18 degrees celcius in no time, but the electricity consumption and the noise is really not good.

please tell me oh wise one which capacity that "3times overdimensioned" unit has that i can see how much (lack of) knowledge you have about airconditioning and laugh out loudly.

for the record: i am living since 39 years in tropical countries and have a wee bit experience as far as airconditioning is concerned tongue.png

The most important thing is to buy an inverter type split aircon, like the one mentioned by indothai it will cool down quickly. it can be on quiet mode and it saves energy if it is not oversized or undersized.

and inverter does not cool faster than a conventional unit and neither can an inverter be oversized nor is the inside unit quieter when full cooling capacity is demanded.

Edited by Naam
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my 18.000 btu samsung aircon if used for 8 hours a night at around 25 dont like it to cold costs me about a 1000 bhat a month bargin

Holy crap, that's near double our total power bill!

and about a quarter of mine

6% of mine!

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my 18.000 btu samsung aircon if used for 8 hours a night at around 25 dont like it to cold costs me about a 1000 bhat a month bargin

Holy crap, that's near double our total power bill!

and about a quarter of mine

6% of mine!

I'm hoping my bill will be considerably lower when I get this piece of Singer <deleted> out of my bedroom, just a few hundred baht will make me happy enough!

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my 18.000 btu samsung aircon if used for 8 hours a night at around 25 dont like it to cold costs me about a 1000 bhat a month bargin

Holy crap, that's near double our total power bill!

and about a quarter of mine

6% of mine!

Infinitely higher than the running cost of a natural indoor airflow system and sensible solar control through sound tropical architecture.

Edited by Morakot
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Infinitely higher than the running cost of a natural indoor airflow system and sensible solar control through sound tropical architecture.

unfortunately airflow, no matter how sophisticated, cannot cool a home. the same applies to architecture which can only slow down the build-up of heat inside a home.

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I'm hoping my bill will be considerably lower when I get this piece of Singer <deleted> out of my bedroom, just a few hundred baht will make me happy enough!

if you keep the "Singer <deleted>" and adjust to a sleeping temperature of 23ºC you will save a few hundred Baht per month and of course you save the capital outlay for a new unit.

what about keeping a few ice cubes in your underpants? laugh.png

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I'm hoping my bill will be considerably lower when I get this piece of Singer <deleted> out of my bedroom, just a few hundred baht will make me happy enough!

if you keep the "Singer <deleted>" and adjust to a sleeping temperature of 23ºC you will save a few hundred Baht per month and of course you save the capital outlay for a new unit.

The sleep I'm losing from the compressor jumping around outside the door and the fan buzzing, phasing & grinding, even when set to 24, 25, 26, 27 or 28 is worth a lot more than the few hundred Baht saving.

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Naam, I'm not sure you understand how bad this Singer <deleted> is, it's not only not up to my standards, it even gets comments from my neighbours about the noise it makes, and they have even lower standards! It really is the worst quality.

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