Because of QC.

Hi DuitNow, reading your first post, these keywords clue in on your situation:
Room area: 4x4=16m2 or 172.22sqft
Other clues:baking room... either single storey or top floor of multi story house. Most likely roof has no insulation under roof tiles. Possibly also room face W,SW or S and/or it's a corner unit facing those direction.

Based on an old post:
Heat load factor: Base + Modifier
Hlf.b=70 (Room with roof w/o insulation under roof tiles)
Hlf.m1 (room face W,SW or S)= 5 or
Hlf.m2 (corner unit with wall facing W,SW,S)= 10
Hlf=70+5 (room faces W,SW,S) or 70+10 (corner unit room facing W,SW,S)
Thus cooling load:
Base only: 172.22*70 = 12,055BTUhr
Room facing W,SW,S : 172.22*75=12,916 BTUhr
Room of Corner unit facing W,SW,S: 172.22*80=13,778 BTUhr

Base and the two modified scenarios suggest that the room's cooling load actually requires 1.5HP.

According to your daily usage duration above suggests an inverter would suit your need for better savings.

This post has been edited by halcyon27: Mar 6 2019, 08:51 PM

If using a non inverter, it will take a while. For an inverter, depending on model, 1HP has a dynamic operating range between 9000-10500BTUhr with some models even up to 11,500BTUhr.

It will be on the high side esp when it's hot and based on what you describe sounds like the compressor works quite a bit.

Even if the furniture takes up space, only your cabinet counts in its reduction but perhaps 10x2 =20sqft. Bed doesn't count as it doesn't take up the whole volume of the perimeter.

A1.5HP will reach set temperature quicker and the compressor wouldn't have to work as hard. A 1 HP can work eventually but it's overworked for the volume.

The room area is one factor. However, more importantly is the amount of heat that is received in that area which is influenced by orientation of the room, building material (walls and roof) and insulating if present. The roof should be the most important one esp if the room is under it. But in condo or ground floor, the floor above is the insulating factor (air) and that would lower the base heat load to 60.

Modern building materials like AAC and roof insulation can reduce the cooling load required by up to half e.g. 0.75HP for your room.

This post has been edited by halcyon27: Mar 8 2019, 10:58 AM

More details needed. Office what floor and what's on the floor above. Where is it's frontage orientation (point of compass)? Is it corner unit and if so where does the exposed corner facade face (compass point)? How large are the windows in terms of area (sqft) in relation to that wall's area (sqft).

This post has been edited by halcyon27: Mar 8 2019, 06:27 PM

Before I answer that, this video will illustrates what is an inverter vs non inverter AC. Some clarification on terms used in India is tonne whereas we're used to HP.
1.0 tonne=12,000BTU=1.5hp
1.5 tonne=18,000BTU=2.0hp
2.0 tonne=24,000BTU=2.5hp

Inverter has dynamic frequency range of operating power vs the fixed frequency of a non inverter. Looking at AC brochure or websites there is a rated cooling capacity stated in kW and BTUhr. Inverters usually states this as z (x-y) kW and also in l (m-n) BTUhr. There's the cooling capacity range. Non-inverters is only one static value. This explains why inverters cool faster for the same HP vs non inverters. Also why when going up in cooling capacity e.g. 1 to 1.5HP, cooling is faster as the dynamic cooling range in the 1.5HP operates at a higher range. When the room is hot, its motor kicks in at high RPM then as the temperature reduces, the motor RPM is slower which means energy saving when running at set temperature. At set temperature, inverters operate at partial load varying as low as between 190-250W depending upon model and cooling capacity. Whereas non inverters operate at its rated power when compressors are active.

This video below illustrates how each achieve its set temperature and maintains it.

Notice the temp variation when compressor cuts in cuts out between inverter vs non inverter esp how often. To compensate, non inverters always overreach by overcooling then cut off. Then it allow the temp to climb and after a threshold temperature, it cuts in again. This makes it +/-1.5-3°C. That's why non inverters feel colder vs inverters for a set temperature e.g. 26°C. Sleeping occupants experience cycles of too chill then too hot over the night. Inverters will maintain a fraction of the set temperature say between +/-0.1-0.5°C depending on model.

Despite the brand, more importantly is generally how it works. Different brands and models vary in implementation technology ie AC vs DC compressor motor; motor operation modes:PAM, PWM or both; safeguards against stressors e.g. rust, voltage tolerance, lighting protection, etc. But the central principle is the same: dynamic cooling.capacity range vs fixed cooling capacity of non inverters.

Ok now to your question, how much energy does an 1.5HP (India uses tonne viz 12000BTU=1 tonne) inverter consume when starting and when reaching set temperature. See below...

Note: allow the variation of temp in the measuring device. It exists as
i. it's may not have the same calibrated sensitivity as the AC temperature sensor.
ii. different location of measurement: one is in the room the other is inside the indoor unit over the cooling fins. The AC temp sensor senses the temperature over the cooling fin to decide when compressor needs to cut in and / or cut out. The temperature in the room is always marginally higher at first because there's heat for the AC to remove. Over time it fluctuates close to that temperature at a certain location and by a wide margin at another location in the room e.g. near ceiling or window on a hot day i.e. easier in the night then on a hot day.

Most important to note is inverter cooling performance will vary model to model as their dynamic cooling capacity range differs. For the same model given the scenario of different room, performance and savings may vary. The key is now much heat is there to remove in each room (kW or BTU) and the required temperature e.g. 26°C vs 22°C

This post has been edited by halcyon27: Mar 8 2019, 10:27 PM

Ok that's a good start.

I calculate 7.875 HP based on gross area but should be lower.

Are there partitioned rooms carved out of this space that should be separately zoned ie meeting rooms or MDs office or should be plainly excluded e.g. pantry room (but not pantry area carved out of the space and is part of it), toilets ie restrooms and common lavatory (wash basin), store room? This could account as haircut for non cooling required spaces. The partitioned zones requiring cooling will be calculated separately based on area.

This post has been edited by halcyon27: Mar 11 2019, 02:10 PM

Yes but toilet and lavatory would be separate right? You can exclude them from the total area and probably come up to 7HP ie 2x3.5HP. Wait maybe with 12 computers, at least 2x4HP may not be a bad idea as they are a constant source of heat. Double check it here which is a more specialised thread taking into account of computing equipment. You might want to see if it makes sense to do 3x3HP or 4x2.5HP depending upon your office layout for better spread. I hazard guess that it'll be ceiling mounted units.

This post has been edited by halcyon27: Mar 11 2019, 10:00 PM

Use a single Mitsubishi Heavy Industry inverter SRK80ZR-S 3.0HP by Trio in Puchong at position A. This one covers all living dining and kitchen and has long air throw.

To overcome the predicament mentioned, you can create a (WxHxD) 13.75'x1.5'x 0.75' deep pelmet that covers over the curtain rod / track, with trough lighting above it if desired and the empty space hides the piping work to the outside (3m minimum). Just ensure the material used on the width of the pelmet can support the weight of the indoor unit. Where the piping is laid, next to it on that wall should be the access panel 30x30cm.

Alternativelyly, make the area look like a series if display shelves that's 1' (12") deep hiding the curtain track except that the AC is positioned centre on a box measuring 4'2" (50") x 1.5 x 1' (WxHxD) with access panels on either side of the box hidden by the shelves.

Ensure all had piping is insulated individually even the drainage so that it won't sweat inside the enclosed area.

This post has been edited by halcyon27: Mar 12 2019, 09:03 AM

Well it's the price of 3x1HP Panasonic. There are not many 3HP wall mounted split units around that are inverter except perhaps for Daikin and York. Most are ceiling mounted cassette which requires 11ft height. And by doing so avoids having 2 additional AC
and electrical points.

Also, it's the only one I can think of inverter, long throw, self clean and 8 vane positioning plus it's a very reliable brand. The 8 vane positioning is due to 3 independent motors for Up-Down, Left and Right air vane movement. And the good part is it fits over a typical 2.5HP piping whereas other 3HP may perhaps require larger pipes.


How much space is above the plaster ceiling?

I've not designed it like that as my air cond are over the walls but this solution is a long thought borne out of seeing many homes having the same predicament. By doing the pelmet, the track is hid. The trick is to ensure the insulation for AC pipes and drainage is insulated and minimal ambient heat seepage into this space. The access panel sound be on both sides. Seal the gap from the outside so they no insects stray into that space.

To implement this you to see if the 3 down light can be repurposed as strip lighting for the hidden track and display shelf-AC box-display shelf. The plaster ceiling may be to be scaled back slightly to accommodate if the height is insufficient...remember clearance is required for opening AC cover for maintenance.

Consult with a carpenter and curtain specialist if the tracks can be mounted on the shelf furniture with a thicker bottom to hold the nails. Or perhaps track that are specifically ceiling mounted but in this case it's on the underside of the shelf-box-shelf. It's skeletal frame could be mild stainless steel etc like how cafes, bistros have ceiling mounted shelves. Just ensure that the area where its mounted is free of or avoids puncturing embedded wiring.

This post has been edited by halcyon27: Mar 14 2019, 09:33 PM

You're welcome and good luck with the reno. Let us know how it turns out even if you didn't go with the MHI.

Inverter have dynamic operation range besides rated at their HP. Can see their brochure which normally should state their specification for cooling range usually in x - y BTU or a-b kW. However these figures are hard to come by in R32 for certain manufacturers esp Mitsubishi Electric but are more prevalent in R410. You can use a converter to derive the BTU from kW.

Non inverters are fixed speed / frequency. So inverters save energy when reached set temperature (Fan speed Auto) as they will revert to a lower frequency to maintain temperature (partial load) whereas non inverters will cut out compressor allowing temperature to decay (rise) before cutting in.

Their compressors can be noisy but mine is located far away to notice. Korean brands needs to follow exactly their compressor minimum space clearance to prevent early burn out. Also if directly outside window, ensure to have 3m minimum piping length to prevent over vibration. They usually recommend one loop to minimise vibration which I thought is a good practice for all ACs.

The Daikins were R410a? What was installed before the Daikins esp those that kaputed?

What error code did the AC emitted? That could give a clue as to what to address by ourselves (filters) or AC technician before continuing operation?

HP is determined by cooling load BTU/HR. I've worked that out for you. Choose one that is within the BTU/HR range. Ensure the model chosen does not operate at the upper bound of the inverter's dynamic cooling capacity range. For that, get the next highest HP.

For example, if cooling load for the room is 11,900BTU/hr get one rated for 12,000BTU/hr (1.5HP or as they say in India 1 tonne). If the cooling load is 14,500BTU/hr, get one rated for 15,000BTU/hr (1.75HP) or 18,000 BTU/hr. (2HP, 1.5 tonne). Most cases of using 1.5HP not cold for MBR on finding out by calculation is because the room size plus taking into account those things that contribute to it's heat load actually exceeds 14,000BTU/HR and seems to suggest higher like 1.75-2HP.

For inverters, inspect the dynamic cooling range in the model's spec sheet ie 1,500-11,500BTU/hr. That means at its lowest, it's cooling capacity of 1,500BTU/hr. Their spec would says something like 8,500BTU/hr @ 700W. From here it's easy to calculate roughly how much 1,500BTU/hr would consume and how much at its highest 11,500BTU/hr will consume. Another clue would be the current draw if its given range if it's disclosed in the model spec sheet eg 1.5-4.5A and at 8500BTU/HR@700W 700W/230V=3.04A

This post has been edited by halcyon27: Mar 28 2019, 10:53 AM

Get a new AC but also pasang new piping. Apart from bad QC is the is possibility of old piping used with R22 refrigerant reused for R410/R32. The compressor lubricant on R22 is mineral whereas the newer gases use PAE (synthetic). Only Mitsubishi Electric compressors can be installed without changing pipes because of the special treatment they added to protect the compressor. The mineral residue of R22 will eventually gum up and ruin the other compressors. To reuse such piping will need a purge and not many installers do that.

Wah this one really very painful to hear. Prioritise which one tho replace according to frequency of usage and budget.

I suggest getting professional installers and AC maintenance guys from now on. A correct AC installation should not leak gas or water. In first world across the causeway, they last a life time and are replace 10-15 years on average barring poor installation or shoddy workmanship.

Also, during cleaning, using the right tool will not even disassemble the indoor unit because that's the main culprit of leakage due to poor joints either by design or improper dismantling and reassembly. Remember, dismantling will expose the pipes and all sort of impurities can enter. Disassembly as reassembly could introduce the chance of improper pipe joints leading to leakages. All depends on the skill of the maintenance crew.

If really kena, you'd get the feedback and cover excuse: not enough gas.

All boils down to whether they check the service information decal of the indoor unit which states serial number, model, year of manufacturer, country of origin and also refrigerant type (R22, R410, R32) amongst other things.

Also it may not be them servicing directly but their workers and miscommunication tends to muck things up.

Things like "Boss tadi kata gas lama" but even that is ambiguous now that R32 is in the picture and they think its R22. The more in the know will say pink colour tong (R410 or Puron) or the gas type specifically.

All boils down to training. Mistakes do happen. Sometimes it helps to tell them but that doesn't guarantee they will not mistake it for something else.

This post has been edited by halcyon27: Apr 4 2019, 03:38 PM

Yes

Can, if you use Mitsubishi Electric only. IIRC, so far theirs are specially treated to protect their compressors when used with piping that previously installed with R22 AC. At least it was for their R410 gas but check with ME distributor (Antah Melco sales) to confirm if only certain range models ie inverter only or all models even up to R32.

This post has been edited by halcyon27: Apr 5 2019, 10:09 PM