Inverter Air Cons

[longball53098]

Hey Guys looking for feedback about inverter air cons versus the old style air cons. I have a 10 year old Mitsu 24k btu unit in my bedroom. It has had several minor failures over the last year or two and I am thinking it is now starting to become more frequent so I am now looking at a replacement. 

A new next door neighbor just built and installed all inverter units mad by Daikin in various sizes. I have talked to several friends that also have inverter machines of various brands. No one has expressed any real discontent with them.

My installer/serviceman has twice now discouraged me from buying inverters and via my wife has said they are too expensive and too expensive to repair when they fail. He wants me to continue using the standard compressor types.

I am asking here for any opinions about Daikin inverters specifically the model FTKM28SV2S whick sells for about 40k to 42k installed. I believe this one has some really nice features. Just to satisfy the question my bedroom is 6.5 meters by 5.5 meters and 2.3 high with staycool in the ceiling and double AAC walls with decent sealing windows. The old 24k btu machine has cooled well all these years so I will look at replacing with a same size unless someone tells me I am wrong. No rush to buy and open to other Brands but from what I hear Daikin makes a great product. I have a Daikin 9k btu in my small office (standard compressor) now 3 years and it works well.

[Stocky]

We've 5 Daikin inverter A/C units in the house, we've had all of them a little over 12 years. They're well maintained and we've had few problems. Last year was the first time we needed to get the local Daikin engineer involved, but bought the spares required and the two units that needed repairs were fixed and are running fine.

 

Yes they are more expensive, though less so now as more and more air conditioners sold are the inverter type. Have they saved me the cost difference in lower electric bills? I've no idea, but they are quiet, none of the compressor start up shut down noises, and they maintain a consistent temperature far better than the old type did.

 

Overall I'm happy with the units we bought, and with the local (Hat Yai) Daikin support on the two occasions we've needed them.

[bankruatsteve]

I am pretty sure "inverter" AC will be the "standard" AC in the not too far off future.  What is now a standard AC will be as hard to find as a vacuum tube TV.  Why?  Because "inverter" is just that much better in terms of energy efficiency, electronics, and temperature control.

 

Your installer doesn't like "inverter" because he probably doesn't know how to repair or that a repair is usually a new circuit board which runs about 5K baht.  BUT Daikin and other mfg have added safeguards to the original problems of spurious voltage and critter invasion (or so they say).

 

Definitely go with "inverter".  If it was me, I would scale down to no more than 18K BTU for that area or even less unless you need frost on the windows. 

[sometimewoodworker]

1 hour ago, bankruatsteve said:

 

Definitely go with "inverter".  If it was me, I would scale down to no more than 18K BTU for that area or even less unless you need frost on the windows. 

Something like this? It's on the outside last week when there was 95%~100% humidity and 5~10 degrees warmer than our bedroom.

[tjo o tjim]

18kBTU should be enough, but the larger unit will reduce your “pull-down” time if you shut it off when not home. 

 

Main benefit of the inverter units is their part-load efficiency is much better, so if you have oversized the unit by 100% the compressor can still maintain temperature without short-cycling. You lose some of that benefit if you oversize it too much though, hence the recommendation for a slightly smaller unit. 

 

The unit you picked is a 26 SEER, so quite good. 

[CGW]

2 hours ago, longball53098 said:

My installer/serviceman has twice now discouraged me from buying inverters and via my wife has said they are too expensive and too expensive to repair when they fail. He wants me to continue using the standard compressor types.

I would imagine he knows he can buy old style AC cheap and has the ability to repair them, Inverter more complex and wont be so many "sales"

 

Daikin is the way to go, as above - 18k should be more than enough for your bedroom space. We have a FTKM28SV2S in the main bedroom, the room is considerably larger than yours, it is more than adequate.

Edited August 26, 2019 by CGW

[bankruatsteve]

2 hours ago, sometimewoodworker said:

Something like this? It's on the outside last week when there was 95%~100% humidity and 5~10 degrees warmer than our bedroom.

Nah.  I get that in the morning with setting on "Dry" - which is my normal for sleeping.  I just think one can really downsize the normal size calculation with inverter.  I have 11K BTU in bedroom but can open door and shutters to let it spill to the living area and it keeps 60 m2 comfortable (with ceiling fans and temp on 25C) and it still goes into low spin even on the hot days.

[longball53098]

Thanks so far for all the great feedback.

Yes I agree he is nervous as if I get a unit that is more reliable he looses some income. Also I guessed the same to his experience and training level. He may be old school and does not know the ins and outs of the new technology. But came came round today to quote a price installed for the one I mentioned.

I have thought of lower sizing but never considered the 18k unit! The FTKM24 is about 5k cheaper and the 18k is even more of a cost savings. That would save some bucks on the total cost for sure but can I count on the 18k or 24k unit being adequate? Now I do shut the unit off about 7am and only back on about 6 PM as I am in my office space most of the day so no need to cool the bedroom just to keep it cool. 

[bankruatsteve]

You never did say what temperature you like but I'm pretty darn sure 18K would be plenty at 25C and probably even lower.

[lopburi3]

Indeed it will often be your temp need as to size - for use in a 26sm bedroom 9k BTU has been adequate with old Panasonic normal unit and more than adequate with Daikin inverter but we kept normal unit at 28 and inverter is normally 29 or 30 (just feels that much cooler as consistent).  

[tjo o tjim]

How many sides of your bedroom are exterior, and do you have a unit in the office too?  18k is enough to maintain about 7C below outdoor temperature with three exterior walls after the sun goes down. I would guess pull-down time from 27->23 would be an hour or so, but my napkin isn’t big enough for that one. (33->27 during the day would be much slower.)

[Stocky]

1 hour ago, longball53098 said:

He may be old school and does not know the ins and outs of the new technology.

The local Daikin engineer has been very good. After we had problems with a unit last year I got his mobile number, the general A/C guy, who we've used for years to clean, top-up and fix minor stuff, has called the Daikin guy a few times for help and they've been good enough to give him guidance, I've been pleasantly surprised.

[Naam]

10 hours ago, longball53098 said:

My installer/serviceman has twice now discouraged me from buying inverters and via my wife has said they are too expensive and too expensive to repair when they fail. He wants me to continue using the standard compressor types.

your installer/serviceman is right because he does not believe the fairy tales about inverters spread by marketing departments and outrageous savings claims from users.

 

Quote

can I count on the 18k or 24k unit being adequate?

I do shut the unit off about 7am and only back on about 6 PM as I am in my office space most of the day so no need to cool the bedroom just to keep it cool. 

based on the above you could rest assured that a 12k btu/h is adequate but of course you won't believe me.

[Naam]

4 hours ago, longball53098 said:

Also I guessed the same to his experience and training level. He may be old school and does not know the ins and outs of the new technology.

there are no big ins and outs as there nothing to repair. the added technology is modular, i.e. expensive modules are replaced even if a tiny component fails. but you have to look at the bright sides of inverters:

-wife/girlfriend wants more sex,

-electricity bills shrink dramatically and might even disappear, in rare cases refunds from the PEA enabling you to upgrade from a Honda Click to a 7-series BMW,

-your dogs enjoy a healthier environment,

-food served in your home will be tastier

and last not least

-global warming will stop and reverse.

 

all afore-said based on my[not so]humble view.

 

[recom273]

I wanted to buy a Daikin inverter but our local guy said, a Thai made eminent 12k btu unit was just as good, bought it from Lazada 12500 thb. I use it in my office 12 hours a day, 30 days a month, it uses about 1000B worth of electricity a month, so far I have been impressed, I set it to 28 and a thermometer in my room measures 28 all day long throughout the hot season. I don’t think that’s an outrageous claim, 250B a week for a week of comfort. 

[RideJocky]

Inverters are great, but if your air conditioner is sized such that it runs wide open all the time, the inverter will not save any money.

If you have a large room and really want to upgrade, buy a cassette style unit. More expensive, but air circulation is much better, they’re (IMO) more attractive and there is virtually no maintenance, as the fan stays dry. They also use a prop rather than a squirrel-cage fan, and pump the condensate out rather than having to depend on gravity.







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[canopy]

I have a Daikin inverter, the most expensive one, and there are 3 problems with it people should be aware of:

 

1. The closest service technician is two provinces away and he told me he would not drive to me for less than 6000 baht.

 

2. The unit has all sorts of nifty filters but strangely they have never caught anything for years. They all stay pristine with never any dust on them. Dust collects on the drum inside and the technician needs to come periodically to open it up and clean it with a water jet otherwise the compressor doesn't run. This is extremely expensive. I asked why the filters don't catch the dust and instead it sticks to the blower and he said it's because the particles are too fine for the filters.

 

3. It doesn't always blow air as cold as I would like as can be seen by measuring the current it is drawing at any time. The technician said it will only run the compressor at maximum power when the blower is at maximum speed. This is very noisy to get it to do what I want. I would prefer a low fan, high cooling capacity but it can't do this like other air conditioners.

 

[bankruatsteve]

12 minutes ago, canopy said:

This is extremely expensive. I asked why the filters don't catch the dust and instead it sticks to the blower and he said it's because the particles are too fine for the filters.

 

3. It doesn't always blow air as cold as I would like as can be seen by measuring the current it is drawing at any time. The technician said it will only run the compressor at maximum power when the blower is at maximum speed. This is very noisy to get it to do what I want. I would prefer a low fan, high cooling capacity but it can't do this like other air conditioners.

 

You call the Daikin tech to clean it?  In our case, the AC guy we have used for "normal" AC repair doesn't have the kit to repair "inverter" but does clean them.  He's cleaned my Daikin inverter several times.

 

Your #3 doesn't sound like an inverter unit nor a Daikin.  Just sayin.

[canopy]

15 minutes ago, bankruatsteve said:

the AC guy we have used for "normal" AC repair doesn't have the kit to repair "inverter" but does clean them.

 

Great idea to use a normal AC guy for cleaning.

 

As for #3 my understanding is inverters are different than normal AC units in that they vary compressor power where normal units are either full blast on or off. So #3 sounds like something only an inverter could do and I am not sure why it makes you think otherwise.

 

Due to the problems I outlined I asked the technician point blank if my unit was genuine Daikin and could verify the model was correct (FTXZ18NV1S/RXZ18NV1S) and he said yes and yes. As he comes from a different province and has technical knowledge being the official Daikin rep I feel his information should be unbiased and accurate. It cost about 70000 baht.

 

[bankruatsteve]

17 minutes ago, canopy said:

So #3 sounds like something only an inverter could do and I am not sure why it makes you think otherwise.

It cost about 70000 baht.

I put my fan on "Auto" and there is always cold air coming out even when on "Dry" mode and the fan is barely poofing.  I thought the compressor worked on temp versus fan speed, but maybe not.  

 

I think those units are available for a lot less than 70K but perhaps it's your location.

[Beggar]

I have 2 older conventional Daikins and there are always problems. They have not been used much because I am not here in my condo all the time. Now I have to replace the inside fan motor at one unit. The part alone costs almost 5000 Baht + work. Also the plastic that was white before is now brown/yellow. The LCD display of the remote is now almost impossible to see. I had to do with many different brands before because before I always stayed in rented appartements. Never had problems with these other aircons. And white remained white and the LCD was easy to read. 

 

In respect of inverters and repairs I have heard bad stories. Inverters seem to be expensive when you buy them and when you repair them. 

[Beggar]

1 hour ago, canopy said:

I have a Daikin inverter, the most expensive one, and there are 3 problems with it people should be aware of:

 

 

How is your experience with dehumidification? I am worried that at inverters the evaporator coil of the inside unit does not get cold enough (dew point) to take out enough moisture at least if the compressor runs at low speed. 

[tjo o tjim]

1 hour ago, bankruatsteve said:

Your #3 doesn't sound like an inverter unit nor a Daikin.  Just sayin.

If the unit thinks the load is satisfied the supply air temperature will be increased as the compressor throttles back to minimum. 

[canopy]

1 hour ago, bankruatsteve said:

I think those units are available for a lot less than 70K but perhaps it's your location.

Nope. Homepro wants 90000 in not only my area but all over Thailand. Online ordering elsewhere is 70K so that's what I did.

 

52 minutes ago, Beggar said:

How is your experience with dehumidification? I am worried that at inverters the evaporator coil of the inside unit does not get cold enough (dew point) to take out enough moisture at least if the compressor runs at low speed. 

I think you are right. When the compressor is running strong it dehumidifies very well. But when it throttles back a lot say at night the humidity becomes noticeable.

 

38 minutes ago, tjo o tjim said:

If the unit thinks the load is satisfied the supply air temperature will be increased as the compressor throttles back to minimum. 

If the fan is set to low the compressor will refuse to go to maximum power even if it's hot as blazes inside which I demonstrated to the technician showing him the power consumption was a fraction of what it was capable of. He said that's the design. And sure enough when going to the loudest fan speed it would increase power to the compressor. I don't like this. These things make me wish I didn't have an inverter.

 

[sometimewoodworker]

3 hours ago, canopy said:

I have a Daikin inverter, the most expensive one, and there are 3 problems with it people should be aware of:

 

1. The closest service technician is two provinces away and he told me he would not drive to me for less than 6000 baht.

 

2. The unit has all sorts of nifty filters but strangely they have never caught anything for years. They all stay pristine with never any dust on them. Dust collects on the drum inside and the technician needs to come periodically to open it up and clean it with a water jet otherwise the compressor doesn't run. This is extremely expensive. I asked why the filters don't catch the dust and instead it sticks to the blower and he said it's because the particles are too fine for the filters.

 

3. It doesn't always blow air as cold as I would like as can be seen by measuring the current it is drawing at any time. The technician said it will only run the compressor at maximum power when the blower is at maximum speed. This is very noisy to get it to do what I want. I would prefer a low fan, high cooling capacity but it can't do this like other air conditioners.

 

While I sympathise with you problems, it rather sounds as though the AC maybe oversized possibly by a lot, though oversizing is much less of a problem with inverters I suspect that it is still a thing.

[canopy]

1 hour ago, sometimewoodworker said:

it rather sounds as though the AC maybe oversized

 

Actually by Thai calculations it's undersized. But I don't need one as big as they think because I live where the air is cooler so it doesn't have as high temperature differential to deal with and also have a very well insulated house with thick AAC walls and doors and windows with full weatherstripping. I used online calculators to calculate.

 

[Naam]

On 8/29/2019 at 9:13 AM, Beggar said:

How is your experience with dehumidification? I am worried that at inverters the evaporator coil of the inside unit does not get cold enough (dew point) to take out enough moisture at least if the compressor runs at low speed. 

that's the problem i am facing since i replaced two conventional units (DAIKIN each 12k btu/h) with a single ceiling unit of 36k btu/h. relative humidity in that area with conventionals running 60-65%, relative humidity with the DAIKIN inverter never below 80%. to lower humidity i have to resort to some tricks which however defeat the purpose of installing an inverter.

 

i also was considering a switch from conventional to inverter in my TV-room but found out that the option i use quite often "full power overriding any setting for 20 minutes" is not available. 

 

summary: DOWN WITH INVERTERS!

[lopburi3]

57 minutes ago, Naam said:

i also was considering a switch from conventional to inverter in my TV-room but found out that the option i use quite often "full power overriding any setting for 20 minutes" is not available. 

It is with the Diakin 9k inverter I have - called "powerful" on remote.  Often use when enter hot room.

[RideJocky]

Do your inverter units not have a “Dry” mode?

I’ve been real happy with my inverter unit.

It is worth noting that Carrier units are currently 20-40% cheaper and have a much better warranty than Daikin, and are (IMO) better looking.


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[Aforek]

On 8/29/2019 at 7:51 AM, bankruatsteve said:

On 8/29/2019 at 7:51 AM, bankruatsteve said:

You call the Daikin tech to clean it?  In our case, the AC guy we have used for "normal" AC repair doesn't have the kit to repair "inverter" but does clean them.  He's cleaned my Daikin inverter several times.

 

Your #3 doesn't sound like an inverter unit nor a Daikin.  Just sayin.

 

I have a Daikin inverter , too, three years old, no problem , and I call an AC guy to clean it ( nothing else because there is no problem)  500 bahts ; he seems to know Daikin and maybe he can repair it , but later, later ...