1 hour just to cool down ur master bedroom??

it means ur aircon BTU is not sufficient for ur room size...

Installed 10k BTU on master bedroom.
Normally ppl will go for 13k BTU

This is my aircond list. The living, dining, kitchen, are all connected as seen in the floor plan. It's about 12.3 meters in length and 6.7m in width so about 82.4 sqm or a hair under 900 sqft.



The orange circles are where we intend to put them. We can't put them on the shortest beams because we've got light fixtures on the beams. It's inefficient but I hope, still effective enough.

The dining, living, will run in 8 hour intervals except when we're sleeping in which we'll turn them off. The kitchen ac will be turned on to assist if it gets too warm as that's the most powerful one.

We've an earth tube that's placed 1 meter underground and rigged it  through an ERV + a whole house dehumidifier to move air from the outside and hopefully by the time it's chucked into the house, it's cooled down and drier.

The plan is to keep the house at or below 24c and humidity around +-55% at all times.

My question is, based on the conditions built, is this a realistic expectation from my ac? I'm going under the assumption of 20 btu per square feet which assumes I'll need 18,000 btu. I'm getting the 22,500 btu and 30,000 btu ac's to account for the insane heat Malaysia's been smacked with.

Our ac compressors are also underneath the eaves to avoid being in the sun and we've got plants flanking the compressor to hopefully cool the area.

Also, we're getting daikin and mitsubishi because everyone keeps repeating that these two are the best, and also the worst. So we figured we'll just get both and try.

Oh no, I'm not planning to build a server room. It's just that our rooms are usually set at 18c because this is what we're most comfortable with. Back in the UK, 18c requires the heater to run whereas in Malaysia, it's the AC that ends up having a rough time. So we ended up with a VRV system for our previous home but that's a lot of work to maintain. I'm pretty sure the VRV system was an inverter system, but we've sold that house to downsize to the current one.

We're also installing the inverters for our bedroom. So hopefully that works out and doesn't require too much maintenance.

Thank you for the good wishes. Much appreciated.
I see

Let me clarify and see if I understand your messages;

1. It's the stop-start cycle that enables you to notice the difference in inverter and non-inverter AC operations. This is probably why I never noticed the difference in most of the places I stayed in.


2. Most AC with BTU that matches the room size will not achieve 18c.

For my setup, our room is a small 4.5m x 5.4m room with 13 feet ceilings. Our rated BTU required was something like 18,000 at 18c. So we've oversized it to the FTKM60TVMM which is a 4000btu - 24,200btu unit.

Considering this, would it still be a tad silly to expect 18C for my unit? If it is, I could install a second unit as it's quite important for us to sleep comfortably in Malaysia. Or I could upgrade the unit to a higher BTU unit too.

My circle of competence is so far removed from this that I haven't the faintest clue how best to approach this. Speaking to my HVAC guys have been quite enlightening but you seem to have a lot of knowledge in this field.


I appreciate you taking the time to comment and help me find a better solution before I bite the bullet on this. The hacking for the piping would be such a hassle so I'd rather know, before we cast the walls.

Just some quick calcs for cooling requirement:
Assuming 24C, 55% RH
-Kitchen (~12500 BTU/hr) = 2hp
-Dining (~13500 BTU/hr) = 2hp
-Living (~17500 BTU/hr) = 2.5hp

Special case for bedroom @ 18C
-Estimated around 26000-30000 BTU/hr = 3hp
1. To put in layman terms, imagine inverter as a 5 speed gearbox. Without an inverter, you can only go between 1st gear and 5th gear ONLY. With an inverter, you can go from 1-2-3-4-5. When an inverter AC hits the required set point temperature you set, the AC can slowly ramp down the motor to meet the cooling requirements and vice versa. An AC without inverter would cycle between ON/OFF so there will be a small duration where you will actually feel it being warm before it being cool again.

For your use case, as you set the setpoint temperature to 18C, your old AC might actually be undersized to meet your cooling load hence it running at max all the time and not turning off when it meets the setpoint

2. Refer estimation of cooling load I did above for the bedroom.

Other notes, there are bigger capacity split units (3hp-5hp+) but they come with ceiling cassette indoor units. Downside is that you need sufficient ceiling height spacing (300mm to 500mm), plaster ceiling (if you want to cover it up) and also open a manhole for servicing it.

Hey thanks for the reply.

So what you're saying is the AC's are slightly oversized for the areas in the main living by about 0.5HP yeah? The above 3 areas however, are all open living spaces so the air will inevitably move all around. Will that be an issue?

For my master, our bedroom is 4 meters long and 5.35m wide or about 230 sqft.

Is that insufficient? I ask because we bought house nearby our construction site and we're staying in the guest bedroom. It's 4.17m long and 2.8m wide bringing it to about 125sqft.

The former owners installed a 1.5HP Sharp AC which we've set to 18 and it runs pretty comfortably, so we assumed that for a 230 sqft room, 2.5hp inverters would do the trick. Are you suggesting we up this to a 3.0HP?

There is some room in the budget to move it up a bit if need be.

for room aircon which u are using every night, i highly recommend to use inverter, not only it will save electricity but most importantly, u will feel the constant temperature throughout the night comparing to non-inverter one..
it will be much much much more comfortable for sleeping...

I'm assuming that you would be spending the majority of your time in the living/dining area so leaving those AC on for when you and your occupants are around should suffice and if it's insufficient, you could run the kitchen island as support AC as per your original idea to zone your cooling areas.

As you also mentioned that you are planning for heat recovery ventilators to be installed, do take note of the placements of where the supply/return inlet/outlet will be as it will affect the cool air distribution within your open space.

As for your master bedroom, I slightly oversized your room. Adjusting to 230sqft, your cooling load is around 23,000 BTU/hr which is in-line with your 2.5hp sizing.

Do take note there are various factors that might affect the cooling requirement:
1. Number of indoor/outdoor walls surrounding the bedroom
2. Number of windows
3. Direction where the windowed wall is facing
4. Insulation
5. Window tinting/Window type (ie: double glazed windows)

Also, in the interest of energy saving, you could try slowly increasing the thermostat temperature from 18C until you reach a point where you no longer feel comfortable. I reckon it will be around 20-22C and would allow better performance should you install AC's with inverters on it.

Cheers

I can attest to this. Ever since changed to inverter ac, feels more comfortable. I sweat very easily and with the previous non inverter AC can feel it gets a little warm whenever the outdoor unit turns off momentarily.

Thinking of getting daikin revo max inverter ceiling aircon. Anybody has experience or review, any issues? Is it much better than the FCFC model?
Besides daikin any recommendations other brand/model ceiling cassette aircon? Thanks

Thinking of getting daikin revo max inverter ceiling aircon. Anybody has experience or review, any issues? Is it much better than the FCFC model?
Besides daikin any recommendations other brand/model ceiling cassette aircon? Thanks

Curious why selection is towards ceiling cassette. High cooling requirement/large area?

Anyway, comparison between the difference of each Daikin split unit cassette series:

FCFC (standard inverter cassette unit)
-Commonly found in shoplots/restaurants that you go to in MY

FCF (similar to FCFC series, more focused towards cool air distribution)
-Individual 4 way air control
-Daikin sensing with a caveat that it requires wired remote controller and sensing panel to be purchased (IR sensor module to focus cold air at areas with occupancy)

Revo max (mainly focused for aesthetic and indoor air quality)
-Aesthetic design
-Daikin streamer tech
-Active plasma ion
-PM2.5 filter

Price in increasing order:
FCFC Series-> REVO Max -> FCF Series

Energy Efficiency:
FCF > FCFC = REVO Max

You can consider other usual AC brands like Mitsu, Pana, York, Midea, Haier similar in spec to the FCFC and FCF series but I think Daikin is the only one that has cassettes designed for aesthetic purposes. Other sifus do correct me if I am wrong.

Not sure regarding reliability, warranty and spare parts availability so I won't comment on that.

Cheers

Curious why selection is towards ceiling cassette. High cooling requirement/large area?

Anyway, comparison between the difference of each Daikin split unit cassette series:

FCFC (standard inverter cassette unit)
-Commonly found in shoplots/restaurants that you go to in MY

FCF (similar to FCFC series, more focused towards cool air distribution)
-Individual 4 way air control
-Daikin sensing with a caveat that it requires wired remote controller and sensing panel to be purchased (IR sensor module to focus cold air at areas with occupancy)

Revo max (mainly focused for aesthetic and indoor air quality)
-Aesthetic design
-Daikin streamer tech
-Active plasma ion
-PM2.5 filter

Price in increasing order:
FCFC Series-> REVO Max -> FCF Series

Energy Efficiency:
FCF > FCFC = REVO Max

You can consider other usual AC brands like Mitsu, Pana, York, Midea, Haier similar in spec to the FCFC and FCF series but I think Daikin is the only one that has cassettes designed for aesthetic purposes. Other sifus do correct me if I am wrong.

Not sure regarding reliability, warranty and spare parts availability so I won't comment on that.

Cheers

Thank you so much for the comprehensive summary. Guess boils down to which model.
As to why ceiling cassette,  home minister mau, say now the trend. Kita ikut je home minister requirements

Okies.. can recommend me anything else? I see hisense inverter 1.5hp cheapest can get here. My fren keep recommend me panasonic for inverter, said easiest get spare parts if antthing broken.

Tcl brand ok ka?

York acson under daikin.

Hi, want to ask anyone engaged cleaning service from Daikin GoClean before? Mind sharing your experience?

Have a 2.0HP Panasonic inverter air cond that’s not been serviced for more than 2 years, been having some leaking issue with those clear jelly-like things. The guy we usually use is quoting quite expensive, and they always remove the whole indoor unit to wash, then citing need to refill gas etc.

Or if you have recommended service personnel/shop to recommend around Seremban area.