Aircon Choice

[Greenside]

I found a thread from 2009 (see here) that answers some of the questions about inverter v regular units, but the price premium has narrowed a bit since then as far as I can see and the increased availability means more of you guys may have had real life experience to draw on, so....

I have decided to install aircon in two rooms: one bedroom of about 47cu m and one room, initially a bedroom but destined to be an office, of 40cu m. For reasons of economy, we use air at night as little as possible - probably a maximum of 35 nights a year and set to 22 degrees or so, although when the smaller room becomes an office the heat of the mainframe (kidding, but I do have a lot of hard drives) it will be needed for much of the hot season to make the room comfortable. The questions are:

• Is it worth the extra outlay for an inverter in terms of power savings - if you've been using one did you see a noticeable drop in your bills? We can only expect electricity to keep rising and since Pork has gone up more than 20% since Songkran, who knows where we'll all be by this time next year?
• Are they proving at least as reliable as the older models?
• I read about multi units where one outside compressor runs several indoor fan units and as I understand that inverters are more effective when run for long periods of time it sounds like it makes sense to run one to feed two. Anyone researched or bought one?
• Finally - inverter or otherwise: any specific recommendations based on reliability, noise and cost in that order.

I'll post a picture of our project in Chiang Mai when it gets a bit further along.

Edited June 2, 2011 by Greenside

[bankruatsteve]

Well, 40 some cubic meters sounds like a really small room to me. While I do not have experience with the inverter units, I have checked and I haven't seen any available for the smaller units - and you would not need more than 7-9K BTU for the rooms you mention.

BTW: why would you not want to run the A/C at night?? That's about the only time I do use it. (and my house is pretty good insulation). But, I like 27C for nice and comfy - then the wifey turns it off about 2-4am.

Edited June 3, 2011 by bankruatsteve

[katabeachbum]

Well, 40 some cubic meters sounds like a really small room to me. While I do not have experience with the inverter units, I have checked and I haven't seen any available for the smaller units - and you would not need more than 7-9K BTU for the rooms you mention.

BTW: why would you not want to run the A/C at night?? That's about the only time I do use it. (and my house is pretty good insulation). But, I like 27C for nice and comfy - then the wifey turns it off about 2-4am.

Simplify and go inexpensive

9k BTu should cover your needs, Samsung and LG are both inexpensive and reliable.

Superquiet, Fujitsu, still havent seen anys spec with lower dB, but comes at a higher price and the fan is rather slow when Superquiet

[transam]

Daikin Inverter.

[Greenside]

You can get inverter units for all sizes (well, 9000 BTU and up) and yes, the office is a fairly small room. I know the sizes I need to buy, it's just the questions in my OP I'd like some advice on please.

[transam]

You can get inverter units for all sizes (well, 9000 BTU and up) and yes, the office is a fairly small room. I know the sizes I need to buy, it's just the questions in my OP I'd like some advice on please.

Daikin Inverter, NO clicking on and off, which drives me up the wall in places l have slept, just the fan noise which is adjustable in the handset as well as fan swing or static.

[Beardog]

We put in a Toshiba 9000 BTU for our 66 cubic meter BDR. -Only use it for the same going to sleep during hot season & whenever else when we need it. Set it to 22 & run it on timer mode for 1 hr or 2 if needed. Very quiet & efficient.And cheap to run 100 baht or so a month (it looks like on difference of electric bill)

I think if you are planning to use it in the same fashion an inverter would be wasting funds. It would probably take till your 100 years old to make any recoup of the extra funds spent. most of the new machines are super efficient & do not cost much to run as a sleeping unit used hourly instead of continual. Naam has some pretty good advice on the posts you read! He has a ton of AC units & his advice on inverters is the same as given. If you intend to use continuously an inverter may be worth the investment. The Toshiba is also a lot quieter than the Diakon also. The fan motor is barely heard on the 3rd speed.

[wandrinstar]

Don't buy anything other than Inverters,or buy the old type very very cheap.I run 4 in the house 24/7, and the saving is substantial. Ive changed the Fridges too.

[Naam]

I have decided to install aircon in two rooms: one bedroom of about 47cu m and one room, initially a bedroom but destined to be an office, of 40cu m. For reasons of economy, we use air at night as little as possible - probably a maximum of 35 nights a year and set to 22 degrees or so

-a 22ºC setting when the outside temperature is 28º or higher rules out any inverter

-the same applies for "35 nights a year" usage.

although when the smaller room becomes an office the heat of the mainframe (kidding, but I do have a lot of hard drives) it will be needed for much of the hot season to make the room comfortable.

-"making the room comfortable" does not mean anything. some people feel comfortable at 30º, others sweat at 22º. so what temperature do you want to achieve? 25º or below during the hot season = forget about an inverter unit because it's wasted money.

I read about multi units...

please make up your mind. do you want to cool one room or more?

[Naam]

Are they proving at least as reliable as the older models?

the jury is still out, no verdict yet. fact is that inverter units contain more [expensive] parts which can break down.

as I understand that inverters are more effective when run for long periods of time it sounds like it makes sense to run one to feed two

i apologise for not commenting on fairy tales :jap:

[Naam]

[chaihot]

My answer is similar to the one given by Naam. (I hate it when that happens).

An inverter is best for people who run their aircon all the time. The purpose behind the inverter is its' ability to adjust. If all you do is run it for a few hours a day, you will never get the benefit of the inverter expense; nor the benefit of the inverter efficiency.

From the web:

While these systems tend to look less efficient at full load (ie their star rating at rated capacity is not always as high as conventional air conditioners), they tend to be very efficient at part load operation, which is a more common mode in a typical household.

So if you are likely to use an air conditioner for long periods because you live in a hot climate, it may be worth considering an inverter system.

[Greenside]

I have decided to install aircon in two rooms: one bedroom of about 47cu m and one room, initially a bedroom but destined to be an office, of 40cu m. For reasons of economy, we use air at night as little as possible - probably a maximum of 35 nights a year and set to 22 degrees or so

-a 22ºC setting when the outside temperature is 28º or higher rules out any inverter

-the same applies for "35 nights a year" usage.

although when the smaller room becomes an office the heat of the mainframe (kidding, but I do have a lot of hard drives) it will be needed for much of the hot season to make the room comfortable.

-"making the room comfortable" does not mean anything. some people feel comfortable at 30º, others sweat at 22º. so what temperature do you want to achieve? 25º or below during the hot season = forget about an inverter unit because it's wasted money.

I read about multi units...

please make up your mind. do you want to cool one room or more?

Sounds like inverters are not for us! BTW, I thought my post was very clear - we have two rooms to cool at night for the mid term and then one during the day and one at night and for what it's worth I usually set a daytime temp of 25 and a night time one of 22 and regard them as my comfortable setting.

From what you say, if a setting of 25 degrees during the hot season rules out the use of an inverter it seems to me that they'd be pretty much useless in Thailand for most people at the time they need them most. I don't know anyone who sets their thermostat much higher than that. You have to wonder why they sell them.

Edited June 4, 2011 by Greenside

[wandrinstar]

Sounds like a load of Hot Air to me. Central Air Changed 4.They Switched them on,and the only difference is lower Noise and lower Bills.

[sotsira]

I have a Daikin Inverter and use it at night set to 26c and works very efficiently and quietly.

My bills have been reduced to half of what they were before with a conventional A/C unit.

Well worth paying a few thousand baht more due to the long term savings off the electric bill.

[User3]

Sounds like inverters are not for us! BTW, I thought my post was very clear - we have two rooms to cool at night for the mid term and then one during the day and one at night and for what it's worth I usually set a daytime temp of 25 and a night time one of 22 and regard them as my comfortable setting.

From what you say, if a setting of 25 degrees during the hot season rules out the use of an inverter it seems to me that they'd be pretty much useless in Thailand for most people at the time they need them most. I don't know anyone who sets their thermostat much higher than that. You have to wonder why they sell them.

The intent of an inverter controlled compressor is to allow the compressor motor to run at reduced load (therefore power) after the room temperature requirement has been satisfied. This reduced compressor speed requires less electricity which is where the savings come in. In order to see a savings you need to have the aircon(s) sized properly for the room area. There is no requirement to run them a long time. There is no particular requirement to have a specific thermostat setting. All that is important is that the unit be on long enough for the room to be cooled and the compressor to start cutting back.

In our experience, we have used Daiken inverters. Not for any particular reason other than good price, good reputation etc. The house is 233 m.2 on two floors. Bottom floor is open plan. There are 2 aircons there that are run about 4 hrs a day- sometimes 5 or 6 but normally 4. Upstairs are one each inverters in the master bedroom and movie room, and an old Mr. Slim in the guest bedroom. The master b/r aircon (set at 25 deg) is run from 9 pm until about 3:00 am when the timer shuts it off and the ceiling fan takes over. The movie room air con is used about 2 hrs a day every second day or so. The old style in the guest bedroom is almost never used- don't get many guests... might be my deodorant......

We also have Inverter fridge and an Induction cooktop. (Bear with me, there is an end to all this in sight.) So cooking on electricity only- no gas in the house.

Our electric bills are usually in the 580 to 620 kw/Hrs a month range.

[Naam]

1. Sounds like inverters are not for us! BTW, I thought my post was very clear - we have two rooms to cool at night for the mid term and then one during the day and one at night and for what it's worth I usually set a daytime temp of 25 and a night time one of 22 and regard them as my comfortable setting.

From what you say, if a setting of 25 degrees during the hot season rules out

2. the use of an inverter it seems to me that they'd be pretty much useless in Thailand for most people at the time they need them most.

3.I don't know anyone who sets their thermostat much higher than that.

4. You have to wonder why they sell them.

1. correct!

2. that is your view. others beg to differ. individual mileages vary.

3. some of my units are set at 27º, some at 26º and two of them (in my study) are set at 25º. our bedroom is cooled down to 18º, the aircon is switched off when i go to bed and switched on again when i get up and the Mrs goes to bed.

4. it so happens that a lot of people feel comfortable at 26-27ºC and a relative humidity of 60% when the temperature outside is 30-34º combined with 80-95% humidity.

[Naam]

My answer is similar to the one given by Naam. (I hate it when that happens).

[transam]

I have a Daikin Inverter and use it at night set to 26c and works very efficiently and quietly.

My bills have been reduced to half of what they were before with a conventional A/C unit.

Well worth paying a few thousand baht more due to the long term savings off the electric bill.

Yep, agree.

Even forgetting the extra initial cost the quietness of the unit is worth it.

[Naam]

Yep, agree.

Even forgetting the extra initial cost the quietness of the unit is worth it.

for the record: the decibel level of the indoor fan depends on its fan speed setting. these settings are fixed and not controlled by the inverter which controls stepless compressor and condenser fan speed in the outdoor unit by variable voltages. any perception of "quietness" is therefore subjective or imagined.

thanks for not listening

[wandrinstar]

Yep, agree.

Even forgetting the extra initial cost the quietness of the unit is worth it.

for the record: the decibel level of the indoor fan depends on its fan speed setting. these settings are fixed and not controlled by the inverter which controls stepless compressor and condenser fan speed in the outdoor unit by variable voltages. any perception of "quietness" is therefore subjective or imagined.

thanks for not listening

Our Pleasure,we are all wrong..

[Beardog]

Quote: Sounds like a load of Hot Air to me. Central Air Changed 4.They Switched them on,and the only difference is lower Noise and lower Bills.

We got our Toshiba from Central. They were the ones that talked me out of the Diakon inverter after I told her we were only to use it for an hour or so in the night. I think at what little baht it consumes - probably 200-300 baht in hot season as Bang Saray always has a pretty good breeze to cool the house down(less extreme hot season , it is just plain hot!) an inverter would take so many years to pay for the difference of price. I would agree with Centrals assessment of needing an inverter when using it a lot opposed to just a quick cool down. That & they also earned respect on just not laying another farang down the road for the higher commission.

[wandrinstar]

Quote: Sounds like a load of Hot Air to me. Central Air Changed 4.They Switched them on,and the only difference is lower Noise and lower Bills.

We got our Toshiba from Central. They were the ones that talked me out of the Diakon inverter after I told her we were only to use it for an hour or so in the night. I think at what little baht it consumes - probably 200-300 baht in hot season as Bang Saray always has a pretty good breeze to cool the house down(less extreme hot season , it is just plain hot!) an inverter would take so many years to pay for the difference of price. I would agree with Centrals assessment of needing an inverter when using it a lot opposed to just a quick cool down. That & they also earned respect on just not laying another farang down the road for the higher commission.

Where did i mention anything about Diakon, or any brand.I didnt even ask them,they have never let me down in 19Years,and i ain that strapped for cash toobother,as long as it works well.

[transam]

Yep, agree.

Even forgetting the extra initial cost the quietness of the unit is worth it.

for the record: the decibel level of the indoor fan depends on its fan speed setting. these settings are fixed and not controlled by the inverter which controls stepless compressor and condenser fan speed in the outdoor unit by variable voltages. any perception of "quietness" is therefore subjective or imagined.

thanks for not listening

That'a strange, set mine on auto fan speed and it slows down when temp is achieved and speeds up when necessary automatically.

[Naam]

Yep, agree.

Even forgetting the extra initial cost the quietness of the unit is worth it.

for the record: the decibel level of the indoor fan depends on its fan speed setting. these settings are fixed and not controlled by the inverter which controls stepless compressor and condenser fan speed in the outdoor unit by variable voltages. any perception of "quietness" is therefore subjective or imagined.

thanks for not listening

That'a strange, set mine on auto fan speed and it slows down when temp is achieved and speeds up when necessary automatically.

"autofan" mode switches between the various available fanspeeds. most units have 5-6 different speeds and i have never experienced any unit which was not extremely quiet at the lowest 2 speeds. autofan mode is available with almost all units manufactured in the last 6-7 years and not limited to those where the compressor and condenser fan are regulated stepless. to the best of my knowledge no units are on the market where the indoor fan is stepless too.

[katabeachbum]

Yep, agree.

Even forgetting the extra initial cost the quietness of the unit is worth it.

for the record: the decibel level of the indoor fan depends on its fan speed setting. these settings are fixed and not controlled by the inverter which controls stepless compressor and condenser fan speed in the outdoor unit by variable voltages. any perception of "quietness" is therefore subjective or imagined.

thanks for not listening

That'a strange, set mine on auto fan speed and it slows down when temp is achieved and speeds up when necessary automatically.

"autofan" mode switches between the various available fanspeeds. most units have 5-6 different speeds and i have never experienced any unit which was not extremely quiet at the lowest 2 speeds. autofan mode is available with almost all units manufactured in the last 6-7 years and not limited to those where the compressor and condenser fan are regulated stepless. to the best of my knowledge no units are on the market where the indoor fan is stepless too.

as I said in post #3, simplify and go inexpensive

With OPs very limited use, ROI on Inverter tech will never appear.

Noise from outdoor unit is mostly desided by where it is installed, mine can not be heard inside rooms, only from bathrooms.

Indoor units noise is decided by its design and fanspeed only, not by compressor. Most are quiet when slow, Fujitsus are Superquiet when very slow

As for comfort temp, I set all on 26 even tho in my homecountry I could not sleep if warmer than 15 and would usually be down to 5 with open window in winternights.

TH humidity and outdoor temp makes 26 comfy for me, daytime in study, nightime in bedroom, 24 hours cost me approx 2.200 baht/month, 24 sqm rooms with 2 x 2,5 meter windows floor to 2,20m. Fujitsu 13BTU

[wandrinstar]

Transam, ive just tried to listen , i think mine do too, never thought an Air Con could be debated so much, mine all went tits up afrer 17/18 years of good service,so the good folks changed em for the latest type..Did u know Pepsi goes Flat quicker than Coke. :D

[Naam]

I have a Daikin Inverter and use it at night set to 26c and works very efficiently and quietly.

My bills have been reduced to half of what they were before with a conventional A/C unit.

Well worth paying a few thousand baht more due to the long term savings off the electric bill.

you didn't change your conventional idea for fun but most probably because it was an outdated and inefficient old rattler, i.e. your claim has no basis.

[bbradsby]

The HVAC pros I know said some time in the distant past to slightly undersize your a/c units so they didn't 'short-cycle' (compressor kicking on and off frequently) due to an over-capacity of the compressor compared to the heating load. As the compressors draw the most current of all the system components, and they draw the most when switched on, this made sense to me. It can also be fairly assumed that short-cycling also wears out the system components more quickly.

Naam, do you agree with the above, and if so, does the equation change with inverters? They seem to kick on at full capacity, then adjust downward as air temp approaches the design indoor temp, so start-up amps should be unchanged.

Last item, there's a good aircon sizing calculator at http://www.fairair.com.au/Calculator.Size.aspx but it references AU cities for simple layman's use:

Please select your nearest regional centre

Adelaide

Alice Springs

Bendigo

Brisbane

Cairns

Canberra

Darwin

Hobart

Melbourne

Perth

Sydney

Anybody know which one would be the best analogy for Bangkok's climate?

[sotsira]

I have a Daikin Inverter and use it at night set to 26c and works very efficiently and quietly.

My bills have been reduced to half of what they were before with a conventional A/C unit.

Well worth paying a few thousand baht more due to the long term savings off the electric bill.

you didn't change your conventional idea for fun but most probably because it was an outdated and inefficient old rattler, i.e. your claim has no basis.

The basis of my claim is simple Naam as i now save half of my previous electric costs per month.

Therefore it proved to me that the inverter system is well worth paying extra for the longterm savings.

The old rattler as you put it was actually 7 years old and i sold it on as a second hand sale.