Need Advice Re Air-con

[4.real]

Know nothing about air con except that I need one[or two].

Need advice re size of unit.

Best makes

best company for fitting

how often and what is needed to service it

Also how often should I have my car air-con serviced.

Any help much appreciated.

[billaaa777]

Call this guy. His name is Venus of Aviva Air, one of Pattays largest dealers. I have bought lots of AC from him. He is a nice guy and speaks good english. Phone Number: 09-403-1997 or 038-706-092

[simcity]

if i may , mitsubishi electric , only can be bought from mitsubidhi shop , they will do the fitting , more expensive as other unit !

[4.real]

if i may , mitsubishi electric , only can be bought from mitsubidhi shop , they will do the fitting , more expensive as other unit !

Heard that M/ELECTRIC are good.

What size air con do I need for a bedroom 3 meters by 3 meters?

Also does the size of small attachment next to the compressor [outside] have any significance on the running of the air con?

Thanks.

[simcity]

if i may , mitsubishi electric , only can be bought from mitsubidhi shop , they will do the fitting , more expensive as other unit !

Heard that M/ELECTRIC are good.

What size air con do I need for a bedroom 3 meters by 3 meters?

Also does the size of small attachment next to the compressor [outside] have any significance on the running of the air con?

Thanks.

i have the wide & long , but now they have new models , with cleaning facility ! nano technologie !

the filters, i get them from The old siam as the shop price is to much !

you need to find a shop and go there , to have a look at the brochure for the unit you want .

sadly they are expensive unit around 35000 baht !

the unit have two parts the compressor and the one you have inside .

Also does the size of small attachment next to the compressor [outside] have any significance on the running of the air con?

sorry , do not understand this question , only the compressor outside , size of mine is 870*295*850 ( outside ) 1100*227*325 ( indoor )

[thebounder]

if i may , mitsubishi electric , only can be bought from mitsubidhi shop , they will do the fitting , more expensive as other unit !

Heard that M/ELECTRIC are good.

What size air con do I need for a bedroom 3 meters by 3 meters?

Also does the size of small attachment next to the compressor [outside] have any significance on the running of the air con?

Thanks.

For a 9 sq m room, unless it has a very high ceiling 9,000 BTU should be ok. If you like it really cold go for 12,000 to be on the safe side. LG do decent models at that size which are very good value for money (for my office, last year, I got 4 9,000 and 2 12,000 ones fitted for 100,000). Daikin are generally considered the best, probably cos they give a 5 yr guarantee for the compressor, but are very expensive.

[toptuan]

I've used a Panasonic for three years with good results. Quiet and efficient operation.

Should service anually at a cost of about 600 baht (which includes a thorough cleaning and recharging if necessary). The annual maintenance will really make a positive difference in your electricity bills. I didn't service mine for two years, and noticed an immediate drop in my electric bill after servicing. Also, the massive gunk they cleaned out of the inside and outside unit (particularly the inside one) was a disgusting shock to me! They really do get clogged and filthy pretty easily.

[Vespa]

Always try to go one up on the BTU level.

a 9000 btu cooling a room that just makes the size recommended will be working at 90 to 100% output to do the job - this ends up using more energy.

If you up it to a 12,000 btu ( initially paying more ) , you will be working at a 60 to 70% output of power and should end up saving a bit on the very expensive electric bill.

Another thing I have learned is the outside compressors are now being offered in a composite plastic shell (that does not rust or end up leaving rust marks along the side of your house if mounted) as opposed to the older standard metal shell that ends up rusting in a bit over a year.

Edited October 5, 2006 by Vespa

[Naam]

"a 9000 btu cooling a room that just makes the size recommended will be working at 90 to 100% output to do the job - this ends up using more energy.

If you up it to a 12,000 btu ( initially paying more ) , you will be working at a 60 to 70% output of power and should end up saving a bit on the very expensive electric bill."

*******

i humbly beg to differ but that is absolute *(&*&$! there is no such thing like running at x% output. a compressor runs and draws its rated amps or it does not run and does not consume any electricity.

there is also no rule of thumb what unit should be used for a certain room size. it's the heatload on that room that counts and which should be taken into consideration when selecting the BTUs. windows with direct sun, outside walls exposed to sun, airconditioned rooms on top, below or on the sides, how many people in the room to be cooled are the factors to deal with.

moreover, the relative humidity plays a big role for feeling comfortable. a room with 60% rel. humidity at 28ºC is much more comfortable for the average human being than a room with 80% rel humidity but cooler at 26ºC.

selecting the a/c unit to big means that the compressor runs for a short time only and the dehumidification effect is much lower than a smaller unit that runs for a lengthier time. as far as wear and tear is concerned an electric motor (compressor) lasts longer when continously running then one that is switched on and off very often.

[4.real]

Thanks ever so for the input guys.

Something to go on at least.I have an old air con,no idea what size but had it serviced last year and they changed an old black round cylindrical object[attached to the pipes] for a smaller new blue cylinder. The air con now does not run as cold as it did. I wonder if this has anything to do with it not running as welll as it did.

I had to sevice it because the fluid leaked out.

I have good insulation in the roof.

[4.real]

Thanks ever so for the input guys.

Something to go on at least.I have an old air con,no idea what size but had it serviced last year and they changed an old black round cylindrical object[attached to the pipes] for a smaller new blue cylinder. The air con now does not run as cold as it did. I wonder if this has anything to do with it not running as welll as it did.

I had to sevice it because the fluid leaked out.

I have good insulation in the roof.

PUT DOWN THE WRONG SIZE ROOM

MY BEDROOM IS 4METERS X 4 METERS. WHAT SIZE DO I NEED ?

Thanks all.

[enuff said]

.

Hello 4,

The thing they changed was the "drier" which takes moisture out of the refrigerant. SOP when refrigerant is replaced.

If your unit was an old model, maybe they put the new type refrigerant in it as the old type was extremely damaging to the ozone. The new stuff is not as efficient so the unit doesn't get as cold.

You should really consider getting a new unit. There have been many advances in the last 5 years and they are designed to operate on the new refrigerant. The new ones are much cheaper to operate over-all.

Also consider a model with features like:

Remote control w/ digital temp. and functions read-out.

Auto Fan... this allows the unit to select the optimum fan speed depending on the difference between the incomming (warm) air and the selected temperature. It will save money by slowing the fan and even turning it off entirely when the room gets to the desired temp.

"sleep mode" which automatically lets the temperature rise through the night. Say, you go to bed at midnight with the room at 26C and set the sleep option. As the night goes on, and it gets cooler outside, and you need less air-con (because you are sleeping), the control allows the room temp to rise a few degrees so you don't wake up in the middle of the night FREEZING as can happen with traditional AC controls.

Programed "turn off/turn on" times. If you have a daily schedule, you can have the unit turn off automatically a 1/2 hour before you leave and on again a 1/2 hour before you return. That way you won't forget to shut down in the morning and leave it on all day accidently($$$) AND you won't come home to a stiffling hot room and sweat like a pig for an hour while waiting for the AC to cool the place down.

Most modern units have these features if you get a major brand.

As far as the size, Dr. Naam is correct with a small caveat:

You are specifically talking about a BEDroom, not a meeting room or commercial space. The Dr. knows that there is a great many factors to consider in these applications, for sure.

But, for a bedroom (with the door closed during AC operation), it should be a simple matter to get a size recomendation from a local installer (some mentioned above) in a rule of thumb manner. I would say 9000 would be good for night-time ony cooling.

Hope this helps.

'nuff said

~

[Noel]

IMO you will find Daikin very hard to beat in terms of quality and efficiency.

They are all but inaudible, a feature I particularly appreciate.

They are not the cheapest by a long way, but you will certainly benefit in terms of performance and reliability, not to mention significant electricity cost savings.

As far as aircon's are concerned, you tend to get what you pay for in my experience...

[BlackJack]

stay away from Aircon King

thats all i will say

[karazyal]

if i may , mitsubishi electric , only can be bought from mitsubidhi shop , they will do the fitting , more expensive as other unit !

Heard that M/ELECTRIC are good.

What size air con do I need for a bedroom 3 meters by 3 meters?

Also does the size of small attachment next to the compressor [outside] have any significance on the running of the air con?

Thanks.

The bedroom in my house is about the same size, I get by with a 5800 BTU window unit without any problems. Unless you plan to have 3 or 4 people in your room all the time - 7000 BTU ought to be more than okay.

[4.real]

.

Hello 4,

The thing they changed was the "drier" which takes moisture out of the refrigerant. SOP when refrigerant is replaced.

If your unit was an old model, maybe they put the new type refrigerant in it as the old type was extremely damaging to the ozone. The new stuff is not as efficient so the unit doesn't get as cold.

You should really consider getting a new unit. There have been many advances in the last 5 years and they are designed to operate on the new refrigerant. The new ones are much cheaper to operate over-all.

Also consider a model with features like:

Remote control w/ digital temp. and functions read-out.

Auto Fan... this allows the unit to select the optimum fan speed depending on the difference between the incomming (warm) air and the selected temperature. It will save money by slowing the fan and even turning it off entirely when the room gets to the desired temp.

"sleep mode" which automatically lets the temperature rise through the night. Say, you go to bed at midnight with the room at 26C and set the sleep option. As the night goes on, and it gets cooler outside, and you need less air-con (because you are sleeping), the control allows the room temp to rise a few degrees so you don't wake up in the middle of the night FREEZING as can happen with traditional AC controls.

Programed "turn off/turn on" times. If you have a daily schedule, you can have the unit turn off automatically a 1/2 hour before you leave and on again a 1/2 hour before you return. That way you won't forget to shut down in the morning and leave it on all day accidently($$$) AND you won't come home to a stiffling hot room and sweat like a pig for an hour while waiting for the AC to cool the place down.

Most modern units have these features if you get a major brand.

As far as the size, Dr. Naam is correct with a small caveat:

You are specifically talking about a BEDroom, not a meeting room or commercial space. The Dr. knows that there is a great many factors to consider in these applications, for sure.

But, for a bedroom (with the door closed during AC operation), it should be a simple matter to get a size recomendation from a local installer (some mentioned above) in a rule of thumb manner. I would say 9000 would be good for night-time ony cooling.

Hope this helps.

'nuff said

~

Hi NUFF.

and thanks to everyone for your input. Much appreciated.

I put the wrong size for my bedroom ,it is 4x 4 meters. I have insulated the roof .

I am asthmatic so need dry air at night.You are probably correct re the type of fluid they replaced but they also changed the small cylindrical object that is connected between the compressor and the pipes running into the house. The old one was app 6 inches long but the new one is only a couple of inches long. I wondered if this had anything to do with the 'coldness' of the unit.

Also how much and where should I go to have the fluid checked /added in my car air con?

Thanks in advance.

[C5VETTE]

To calculate the correct size of A/C easy then use the "Thai standard" of 800 BTU per m2. This gives the correct size in a "normal room" at around 3m to roof.

[john b good]

"a 9000 btu cooling a room that just makes the size recommended will be working at 90 to 100% output to do the job - this ends up using more energy.

If you up it to a 12,000 btu ( initially paying more ) , you will be working at a 60 to 70% output of power and should end up saving a bit on the very expensive electric bill."

*******

i humbly beg to differ but that is absolute *(&*&$! there is no such thing like running at x% output. a compressor runs and draws its rated amps or it does not run and does not consume any electricity.

there is also no rule of thumb what unit should be used for a certain room size. it's the heatload on that room that counts and which should be taken into consideration when selecting the BTUs. windows with direct sun, outside walls exposed to sun, airconditioned rooms on top, below or on the sides, how many people in the room to be cooled are the factors to deal with.

moreover, the relative humidity plays a big role for feeling comfortable. a room with 60% rel. humidity at 28ºC is much more comfortable for the average human being than a room with 80% rel humidity but cooler at 26ºC.

selecting the a/c unit to big means that the compressor runs for a short time only and the dehumidification effect is much lower than a smaller unit that runs for a lengthier time. as far as wear and tear is concerned an electric motor (compressor) lasts longer when continously running then one that is switched on and off very often.

I wouldn't debate your opinion but what would you suggest if you are right on the edge (20 M2 which is suggested as the max for a 12,000-13,000 BTU unit)

Would you advise going for a 18,000 BTU model.

Also what are your thoughts as the max length of piping (compressor to inside unit) for a 18,000 BTU unit. Would 10 metres be OK ?

[Tywais]

but they also changed the small cylindrical object that is connected between the compressor and the pipes running into the house. The old one was app 6 inches long but the new one is only a couple of inches long. I wondered if this had anything to do with the 'coldness' of the unit.

That's the expansion valve and can have an effect on how well it works if not matched properly. Here's a good place to find how things work > howstuffworks > Air conditioners

[Naam]

"I wouldn't debate your opinion but what would you suggest if you are right on the edge (20 M2 which is suggested as the max for a 12,000-13,000 BTU unit)"

----

unfortunately there is no such thing as rule of thumb like Xm² require Ybtu/h. it all depends (as mentioned already) on the heatload the room to be cooled receives and what temperature should be reached inside when outside ambient temperature is 35-36ºC (which is the average maximum in thailand). i could write a dissertation on this subject but it would be quite boring for all of us.

requirements vary a lot. e.g. our masterbedroom is around 31m² with a high ceiling (3.50m), three outside walls (bad), a 3m² window to westside (bad), a 3m² window towards a roofed pool area (good as no sun). no a/c running during daytime, required temperature from midnight till morning 26ºC which could easily be achieved with a 9.000btu model not running continously. but we are talking about night time and low outside temperatures!

a different "animal" is my study of 42m², same positioning like the master-bedroom as far as outside walls are concerned but two windows (each 3m²) to the westside. additional heatload from inside sources ~1.000watts generated by three PCs. on a hot and sunny day one single 13.000 unit can manage to maintain 25ºC till 14.00hrs but then an additional 13.000 unit has to kick in till around 17.30hrs although the compressor of the second unit will not run continously.

even the afore-mentioned examples do not provide a guideline as a lot depends what kind of outside walls the building has, what insulation on ceiling tops (if any) and how the attic (empty roof space is ventilated). i have tried hard to design a most energy efficient home and was deeply disappointed when during the first month after moving in my expectations were not met. i calculated my total electricity demand with 100kw/day (12.000 bath/month) and landed up with a 135kw (16.000 baht/month). now, after floors and walls have cooled down, roof insulation is in place and attic is force ventilated my consumption is down to an average of 80kw/day but that with cloudy skies and quite some rain. so my original estimate of 100kw/day average will most probably apply.

worthwhile to mention is that (contrary to most assumptions) the lion share of electricity consumption is not my airconditioning. it is quite balanced (50:50) with other consuming items like pool pump, pond filtration pump, waterfall, two huge fridges/freezers, cooking, hot water supply, lighting, etc.

*****

Would you advise going for a 18,000 BTU model.

------

definitely not except if you have a lot of glass with sun radiation on it.

*****

Also what are your thoughts as the max length of piping (compressor to inside unit) for a 18,000 BTU unit. Would 10 metres be OK ?

-------

basically "the shorter the better" applies. in olden times the rule was "never exceed 7m" but i had to make some concessions with pipe lengths (due to the design of my home) and shamefully admit that out of my 15 units at least 12 have pipe lengths exceeding 10m, 3 or 4 of them even exceeding 15m! i did not realize any difference when measuring the temperature at the evaporator coils but i guess that the units are using 5-10% more energy because of their long piping.

[4.real]

Thanks to all of you for making this an interesting topic.I have learnt quite a bit from all your remarks.

Thanks especially for 'Howstuffworks' I can see it being useful in the future.

4.real

[john b good]

"I wouldn't debate your opinion but what would you suggest if you are right on the edge (20 M2 which is suggested as the max for a 12,000-13,000 BTU unit)"

----

unfortunately there is no such thing as rule of thumb like Xm² require Ybtu/h. it all depends (as mentioned already) on the heatload the room to be cooled receives and what temperature should be reached inside when outside ambient temperature is 35-36ºC (which is the average maximum in thailand). i could write a dissertation on this subject but it would be quite boring for all of us.

requirements vary a lot. e.g. our masterbedroom is around 31m² with a high ceiling (3.50m), three outside walls (bad), a 3m² window to westside (bad), a 3m² window towards a roofed pool area (good as no sun). no a/c running during daytime, required temperature from midnight till morning 26ºC which could easily be achieved with a 9.000btu model not running continously. but we are talking about night time and low outside temperatures!

a different "animal" is my study of 42m², same positioning like the master-bedroom as far as outside walls are concerned but two windows (each 3m²) to the westside. additional heatload from inside sources ~1.000watts generated by three PCs. on a hot and sunny day one single 13.000 unit can manage to maintain 25ºC till 14.00hrs but then an additional 13.000 unit has to kick in till around 17.30hrs although the compressor of the second unit will not run continously.

even the afore-mentioned examples do not provide a guideline as a lot depends what kind of outside walls the building has, what insulation on ceiling tops (if any) and how the attic (empty roof space is ventilated). i have tried hard to design a most energy efficient home and was deeply disappointed when during the first month after moving in my expectations were not met. i calculated my total electricity demand with 100kw/day (12.000 bath/month) and landed up with a 135kw (16.000 baht/month). now, after floors and walls have cooled down, roof insulation is in place and attic is force ventilated my consumption is down to an average of 80kw/day but that with cloudy skies and quite some rain. so my original estimate of 100kw/day average will most probably apply.

worthwhile to mention is that (contrary to most assumptions) the lion share of electricity consumption is not my airconditioning. it is quite balanced (50:50) with other consuming items like pool pump, pond filtration pump, waterfall, two huge fridges/freezers, cooking, hot water supply, lighting, etc.

*****

Would you advise going for a 18,000 BTU model.

------

definitely not except if you have a lot of glass with sun radiation on it.

*****

Also what are your thoughts as the max length of piping (compressor to inside unit) for a 18,000 BTU unit. Would 10 metres be OK ?

-------

basically "the shorter the better" applies. in olden times the rule was "never exceed 7m" but i had to make some concessions with pipe lengths (due to the design of my home) and shamefully admit that out of my 15 units at least 12 have pipe lengths exceeding 10m, 3 or 4 of them even exceeding 15m! i did not realize any difference when measuring the temperature at the evaporator coils but i guess that the units are using 5-10% more energy because of their long piping.

Thank you for your advice.