What's your point using inverter aircond still set in 19-20c?

Do you think on smaller room these still comfortable?

My point is dead simple : inverter air cond only can help you to safe money after you waste more money, nothing more and nothing less.
That's why I rather get a job that only pay me rm3000 and I can stay in terrace house rather than I getting rm6000 but only can stay in <1000sqf of flat that are very poor on ventilation.

Before talking about setpoints, first you need to have the right HP for the room size. That's called rightsizing. If HP is too small you will never reach the set point and the compressor doesn't cut off. That's like trying to drive a kancil at 300kph.
If the HP is too large, the cut off will happen too soon before the compressor reaches optimum efficiency. That's like driving a Ferrari in a traffic jam. Either scenario is wasteful.
Using the right size HP and selecting correct setpoint both need to be done.
Your uncle likely failed to do either, accounting for the excessive bills. Also setting the setpoint at 18oC is the wrong way to use the air-conditioning. Setting at 25 is correct. That is where inverters come into the picture. Basic Air-conditioning compressors work by turning on and off to maintain the set point.
Inverters work by reducing the need to turn off completely. Not only it saves energy, but it reduces wear and tear.

So 18c same as 19-20c, good take, I also forgot about this totally, thanks to pointing on this.
Does my uncle failed like you simply accuse? I doubt so. He has a lot of money, so rm700-800 for him is chicken feed. Like our friend said, setting 25c with low fan speed and turn on 10-12 hours and still getting rm400 bill compare to my uncle's set at 19-20c with 24/7 turn on which cost rm700-800. Who failed? Extra rm300-400 and rooms cold everyday compare to rooms cool for 10-12 hours only, no need to ask also can know which is better, right? If you want to tilt this fact and you'll be happy with this, I'll let you win.
Like you said setting 25c is correct which I'm quite sure you failed totally, by properly design your rooms, getting a room temperature of 25-26c is not hard.

From what I said your uncle really rich, does not matter how cold of the overall temperature there still need set into 19-20c and operate 24/H.

He he you're not wrong, we used inverter unit of the compressor and fan speed will automatic adjusted to suit actual correct way outdoor & indoor speed of variable to adjust to running speed , even you can set into 19c or lowers these can achieved to your set point.

25c is min. for inverter unit from cooling needs, you can set lower but overall really uncomfortable of too cold until your foot feels uncomfortable.

From 19-22c only when using non inverter minimum require.

Anywhere our bro here, you wanna save energy or compare into non inverter or inverter unit, just do your difference rooms and try to set in same temp. and feels which one more efficient and long runs.

1st thing over size room and installed smaller HP will over kill your aircond long runs.

2nd thing set point too low and force the aircond runs until non stop also over kill the compressor rubber mounting life.

3rd thing set too low temp. and fan motor works too heat and over kill the fan motor created noise level.

Having a lot of money doesn't mean he knows everything. Do you even know how cold actually 25oC is? There is a range of combination of temperature, humidity and air movement which is known as the thermal comfort zone, in which human perceive themselves to be comfortable. 25oC is usually the upper limit. In HVAC design, that approximates the max temperature you can go in Summer before it is deemed uncomfortable. On the other hand, 20oC is the minimum temperature you set for heating in Winter before things are deemed too cold for comfort.

To be fair I absolutely agree with your earlier contention that passive cooling and better structural design reduces the need for active regulation via air conditioning. However I cannot abide by the fact that you dismiss setting 25oC as a good practice. It *is* the norm (it should be even higher if we really want to save on carbon emissions). To use another car analogy, you don't floor the pedal if you are just intending to drive at 80kmh

The whole point of all the technological advances in HVAC and environmental design such as inverters etc is that you would want to adjust your living environment so it is comfortable with the minimum drain on resources.
It's not just about the money here.

It's just absolutely wrong to even justify setting 18 or 19 or even 20oC in our Malaysian climate as it is extremely difficult to achieve. To be honest with you I think the majority of Malaysians are ignorant about how air-conditioning is supposed work. An expat friend of mind once remarked how silly and ironic it was to see Malaysians set 18-19oC in their office thermostat and yet come to work clad in sweaters and jackets, complaining it was "too cold".

FYI until recently I lived in a 3 storey house with 8 air-conditioners, (including 2 energy-sucking 2.5 and 2HP cassette units) and my monthly bill was rarely above RM170. That was because I minimized usage of the air-conditioning to just a few hours at night, not seeing the need to blast it on 24x7 and tried my best to use electricity saving devices like inverter fridges, LED lighting etc. It's no point bragging about electricity costing RM700-800 and being able to afford paying for it. It think it's downright shameful nothing more is done to lower it.

just my 2 cents'

Anywhere most of better aircond and design for human control it as comfort, but human aways blame on device an error of usage.

Well said bro.. most of us just dont understand d different between an ice maker and an aircond, and a house and a fridge. 18 degree certainly too cold to live in unless you are a sealion.

If you don't know him, don't simply accuse or label a person, it only show how childish you are.
You can boast you have 8 air conds, but you rarely use it. Some like to put full blast, in this world there's lots of people.
And after using all those inverter or so-called energy saving device your bill still hitting rm170, that's still a waste. With all those stuffs installed, if you can get rm70-80 then I salute you.

Well pointed out.

I'm just pointing out some facts and trying to correct some potentially misleading points you brought up. A lot of what I say is backed up by sound theory. Some of the things you are saying are clearly based on practical experience, but not fully informed by theory, and that makes it dangerous.

If I tell you 25oC is cold enough a setting, then if you are not getting it "cold" enough, it means that something is not right. It means *potentially* one or the other of the scenarios I pointed out. (assuming there is nothing wrong with the workmanship or the installation)
The more common scenario in Malaysia is I believe, people buying air-conds which are way too small because of initial cost consideration, and then switching it at lower temps because they can't get it cold enough. You NEED to right-size.

Having a lot of air conditioners doesn't mean I have to switch all at once in order to get a humongous electric bill: I do accept that usage of air-conditioning will always be higher slightly than having none at all; I *understand* the potential impact on the environment of excessive electricity usage and try to keep within acceptable bounds; I am *willing* to pay for that *small* premium for additional comfort within a reasonable amount, but that is as far as it goes: It's mainly there so that I can have it when I *need* it, e.g. when there's a party and I have like 50-60 guests milling around the premises. I don't think I'm the one being childish or presumptuous here.
I don't need you to salute me because that is not the intention I brought up the matter: you can't fight the laws of physics. You use electricity, there is a price to pay, not just money, but in terms of impact to our environment. That is why we must use what we have responsibly.
If I say 25oC is the correct set point, and you are not getting that, you need to find out what really is the matter. That's all I'm telling you.

As said before, in this world there are lots of people have different way of living.
You like to have inverter products and LED lights and paying rm170 bill and boasting around "I'm saving a lot". I only use the most simple electric appliance and fluorescent lights and only paying rm70-80 bill and I still say it is a lot. Where some more I can make it my bill cost rm40-50.
You say 25c is cold enough, that's for you. For me, 26c already very cold for me. But for my banana relatives that spent 10 years in Europe, they prefer to have cold environment and wearing jacket. Again, are they wrong? I doubt so, that's why I said before, if you know nuts on my uncle, don't simply accuse and label.

Not need to comparison too much for others user like no tomorrow.

The important is you be the user here.

No matter how great or how much of the monthly bill is = you be the paying person.

We would advise you to installed inverter for save power energy and kept min. require for inverter unit as set point for 25c that's good than enough for your room size as 3m, 4m x 3m high.

Once you has installed and come back to tell us how much you can save or really can't tahan lower than 25c there is still in future of you points to view.

Well, I only use the air cond for 1-2 hours everyday, as said again and again inverter will only see the effect after run for long hours.
The maintenance cost also way higher for same HP.
Maybe like this, I can install as per your advise, but if the electricity bill still the same, you buy back that inverter air cond from me for the original price I bought and including the installation and removing fees. All under you. Simple, right?

Care to elaborate on this?
Unless you are replacing/refilling the gas, which is not all the time, the labour cost of just cleaning should be about the same.
Even then it's not always true, because not all inverter air-conditioners use the more-expensive R410A gas, which should be around RM2xx~ (but dropping fast)

Quite reluctant on answer this question, ask your installer better.
Some inverter type are still using the old type, I just don't want to fall in to your word game trap.

That is logic lah... Usage 1 to 2 hours for everyday.

Data here : input watt = 900w and used 0.9kw x 2 hours x 30 days = 54 units of your bill.. I dun think you really need install aircond wow

You don't have to be so defensive or evasive. I'm neither interested in massaging nor bursting your ego, and anything you feel is really a reflection of yourself rather than what others say. None of us here claims to know everything, and we all learn from each other. If something I say is wrong, I'd sooner recant than defend the indefensible because the advice and information given here could potentially cost people money and a lot of inconvenience if taken at face value. Let me remind you that this is a forum for sharing information and seeking advice, not /k or RWI where people thrash talk each other and show the world how stupid they are.

As far as I know there are at least 2 makes (one of them is Daikin, the other I can't remember) in the local market which carry R22 inverters.
When we talk about cost, there's cost of purchase/installation and there's cost of ownership (i.e. maintenance/operation).

When we buy air conds, inverters carry a premium over non-inverters for the same brand due to the extra features.
When we install air conds, we have to consider the gas type, especially for retrofit: New houses that come with air cond piping tend to have thicker piping ok for use by both R22 and R410a type gas. Older houses on the other hand, may not have the thicker pipes and there is the additional cost of retrofitting if you want to use R410a inverters.

When we use air conds, provided they are install correctly and optimized for their environment/use-case, inverters will tend to result in greater savings in electricity bills and maintenance cost due to reduced wear and tear.

In general, you will also find that when air conditioning is installed professionally, there is not a lot of need to refill the gas.

In the case of refilling R22 inverters should cost about the same to refill as normal R22.
R410a inverters on the other hand, have a premium of about RM100 on gas cost last I checked.

I also know that some installers *cheat* a little by saying they completely replace the gas when actually they are just topping up. Comes with the territory and everyone has to cari makan.

I'm sharing what I know based on what I researched when I bought my air-conds because I think we can all benefit. I'm not interested in playing word games with you.

R410A gas inb4 , 4 yrs back I bought my gas R22 at around Rm150 to 180, I can't remember.

But at that time for R410A = Rm450.
Last year I had top up gas for my R410A = Rm100 with labour.
Asking the price for R410A per tank = Rm250.

I don't think of the maintenance will overkill my pocket.

Just note : if your brand new aircond come with pre-gas then you has not require for top up any gas.
Unless you relocated the outdoor unit.

If good workmanship after installed even 3-5 years you worry free for ask Aircon man come back to check gas.

Good workmanship of the cooper pipe connection there be simple simple can be leakaged.

For maintenance to clean out fancoil or clean out drain pipe overflow leakage that is very common.

So do you can decide install or use fan