I kind of agree with this analogy, but not entirely. The problem is the no gearbox car having 2nd gear, because it implies that to go at 110 km/h, the engine is over-revving/over stressing itself. But what if the maximum speed for both the gearbox car and no-gearbox car is only 20 km/h? And it is a clear road with absolutely no other traffic? Then there's no problem for the no gearbox car, right?

So come back to the air cond. If your temperature is set for 18°C, then both the inverter and non-inverter will be running at full speed, all the time. They will only start turning on-off (non-inverter) or varying the speed of the compressor (inverter) once that set temperature is reached. That's why one of the best ways to save electricity consumption, is to increase the set temperature to, say, 25°C. Since the room is able to reach this set temperature, the inverter air cond will start its inverting, and the normal air cond will start its on-off to maintain the temperature.

There is nothing inherently wrong with normal air conds. On-off cycling has been used for ages, and still works. Inverter technology is great to save electricity usage, but only if you are able to reach the set temperature. Otherwise, not really.

Coming back to the car analogy. You drive a tiny car with 600 cc and MUST travel at 150 km/h. Doesn't matter if your car has a gearbox with 5 gears, or only N and 5, both will be in 5th, and with the pedal to the metal to maintain that 150 km/h. And both will have similar fuel consumption.

You are correct, most of the installation manuals from the manufacturer for air conditioner units specify a minimum of 1.5 mm² wire between IDU and ODU for about 2 HP units or below

The power from DB to air cond is wired as a socket point, so the wires will be 2.5 mm², and the MCB will be 20A (I prefer to use 16A)
The IDU and ODU has both power (for the compressor) and signal if you are using inverter air cond (1 extra wire, normal air cond only 3 wires), and like you said, manufacturers specify 1.5 mm² wires for them.

Edit to add:
This is just the first nameplate of an air cond that I found as demonstration only


It is a total of ~2500 Watt, or ~3 HP. The rated current is 11.2 Amps. 1.5 mm² wire can withstand 14 Amps (conditions apply). So, in theory, you can wire up your 1.5 HP air cond from the DB with 1.5 mm² wire and still be safe. But 2.5 mm² is used.

It is similar to water heaters. 2.5 mm² wire can withstand 20 A (again, conditions apply) but Suruhanjaya Tenaga now requires 4 mm² to be used for all water heaters.

I would say it is not a technical reason, but rather an administrative one. ST sets the rules from the DB to the air cond unit, but not from the IDU to the ODU (the manufacturer does that)

This post has been edited by stormer.lyn: Nov 6 2021, 03:13 PM

I just has a quick look on Shopee and a 1.0 is RM 1,415. I don't know what the previous price was.
The price of copper went up about 50% over the last year or so. Since there is a lot of copper piping in the air cond unit, could that contribute to the price rise?

R410 and R32 gassed air conds run at a higher pressure than R22. The manufacturer specifies thicker copper pipe to be used for the gas and liquid line. Could this be the reason for the prices in your quotes? Maybe your installer is quoting to do a proper job, and of course this causes the price to be higher due to the higher price of the pipes. I don't know your installer... I'm just throwing a thought out there.


*No link between me and this Sh*pee store, just chose one that had both thickness of copper pipe listed for this post.

I mostly agree with your statement, except I just want to say a RM 20 difference in the raw material price does not translate to a RM 20 difference in your installation cost when the installer is the one supplying the material. You can't expect the installer to have a material cost, a holding cost, licensing cost, training costs, transport costs etc, etc, and then charge you only the difference in the material cost right?

You were wondering why another poster said that the install cost is RM 180, and why you were getting quotes that were higher. I postulate that maybe it is just because the materials used is different. Other posters also haven't stated their location, nor what year their installation price is from, whereas you are stating you are in KV and want to do this installation currently. So all in all, maybe all the quotes you are getting that are in the RM 250 range is correct, and you are trying to get the RM 180 one that is from Seremban 3 years ago. I don't know, I'm just putting my thoughts out there.



Full disclosure : I am a technical person, now learning how to install, maintain, service and repair cooling systems. I think the air conditioning and cooling industry is going to be one of the sectors resistant to uncertainty in the future, which is why I am moving into it. There's so far thousands of RM spent in tools and consumables, and I still am not done buying everything yet. Oh, I still haven't installed a single air cond yet, but I have repaired 2 air conds for free for family members for the experience. I have to recover all this cost slowly, a bit at a time, over each job that I do in the future, and make a little profit should I want to sustain a business. So I really don't think "Wah the materials cost RM 100 only, why he charge me RM 250" complaint is valid.

Ultimately, do you know what I want to happen? When someone is looking for an air cond installer, you'll say "A bit slow to come because he has a lot of jobs, and a bit expensive lah, but his work damn good and nice. You call stormer.lyn to fix your air cond". This is the customer referral I want

This post has been edited by stormer.lyn: Nov 7 2021, 09:56 PM

Paying a little extra for a s/steel bracket is worth it for long term peace-of-mind. Pay once but use forever is a good outcome. I (consider me a normal consumer) would want a s/steel item if it were mounted outside and exposed to the elements anyway. Try this link in Sh*pee to see some prices.

As for the price, if you are wanting the better option, but would like to save a bit, then you should consider buying your own s/steel bracket. Ask the installer if they will install with your bracket instead of the mild steel one they use. They shouldn't charge you any extra. But please discuss this beforehand with the installer so that no one is surprised, and that everyone is on the same page. The problem in M'sia is that some installers use the materials to generate profit, so whenever you change the material, the cost also changes. When I worked in [redacted], the installer is very happy for the customer to buy the materials as it saves them all the costs associated with buying, keeping and handling the materials.

This really should be a win-win situation : you get the s/steel fitting at a cheaper cost, and the installer charges you the same for the installation, but they have saved on not using their own bracket. In my work, I am very willing to install items the customer provides. Why not? I'm still doing the same amount of work and charging the same amount, but I'm using the materials the customer bought and managed.

Yes, that is totally fine
Edit : on the condition that the air cond installation manual says you can use 1.5 mm² wire

This post has been edited by stormer.lyn: Nov 8 2021, 08:02 PM

Your air cond is low on gas. You should find out WHY it is low on gas instead of just adding gas, as the gas is not a consumable, nor should there be leaks in the system.

This post has been edited by stormer.lyn: Nov 14 2021, 03:43 PM

Something like this can help with making a schedule of the times and temperatures you need.

Disclaimer : Not recommending or not this model, just picking the first one I found. Example store has no association with me.

I am unable to recommend any item without knowing what your model of air cond/software/features you require, but I can say my similar setup does work with my air cond to turn ON/OFF, set temperature, etc, according to a schedule.

There is a discussion similar to what you require in the Smart Home thread.

This post has been edited by stormer.lyn: Jan 17 2022, 08:13 PM

I would say "NO", you are not consuming less than 250W on average. My take would be that with the compressor totally OFF, this is the power used for the electronics, the blower, LEDs, etc, or this is already the average power usage with the compressor turning ON and OFF. If you were to be using less than 250W on average, I am sure the manufacturer will have a * on the specifications, leading to a fine print disclaimer because all manufacturers would want to have lower power consumption in their specifications.

Of course this is only my opinion based on my enginerding qualifications, there having to be some truth in advertising (or the manufacturer could get sued), and also a bit of knowledge on how the industry labels power consumption

You are basically correct, the contractor is not

2 HP (~18,000 BTU) calculates about right for me for a room sized 40 m². I definitely won't want to undersize the a/cond

I'm using the notes from my a/cond certification course. Is there a better tropicalised calculator out there you mind sharing? Hopefully from an independent source, not from a manufacturer (that wants you to buy the biggest a/cond they sell, right? The Daikin calculator puts this room at 30,000+ BTU requirement!)


I agree with you, 40 m² is 430 sq ft, which is as big as a studio apartment. Given that the poster asking says they only like it 25°C ++, they may be better off installing 2 units for better spread of the cool air due to furniture/obstructions.

Oh, so you use calculator.net? That's a pretty common starting point, before we use experience and local conditions to further tune the a/cond sizing.

Just want to point out that with your parameters, the result is 17,142 BTU, which is slightly below most 2 HP a/conds (which are rated about 18k BTU) You wanting to oversize the a/cond unit is your preference, which I think you should have explained. But you have to give the initial tech his due for recommending the 2 HP unit, because it is the correct rating according to size calculations.

I still think the original poster (Edit to add dest9116) will be better off using 2 a/cond units for 40 m² though.*

*Disclaimer : Armchair analysis done from remote location through PC screen

This post has been edited by stormer.lyn: Jul 27 2022, 10:52 AM

Replace only if damaged, they are not consumable items.

Check the actual model number instructions. They will usually have a page like the one below with the spacing required. (Sample of manual only, please don't follow for your air cond installation)

Panasonic produces this model, and they are all shit. Can you imagine the number of complaints?
or
There is something wrong with your unit since day 1, or the tech installed it badly/wrong.

Occam's Razor.

It's okay in the sense that everything will still somewhat work as it is supposed to.

But all these, and more, are possible side effects:
Increase in electricity bill, sooner wear out of equipment, more frequent servicing needed, bad air circulation, complaints of insufficient cooling, etc. The air cond needs to blow into the room with good circulation, and with unrestricted flow. Anything that prevents this will of course reduce the cooling efficiency.