Hi there. I see you're a huge advocate for inverter airconds. I've a double volume space that is 19 feet high and as open plans go, I have combined by living, dining, kitchen area into one stretch. It's 90 feet in length and 21 feet in width so bringing my total area to 1890 sqft or 35,910 cubic feet of space.

We also have a 12 foot fan that will be installed in the middle of the space for circulation of air between the spaces.

We're lowering the AC to be installed at the 10 feet height of course, not planning to bother with cooling up top.

We're planning 6-8 wall units for the space, as we enjoy keeping the house temperature to a max of 20c, 55% humidity. We're aware that we're living in the wrong country for this temperate needs, but otherwise Malaysia is such a great country.

Would an application like this still justify a inverter, seeing that it only starts to reduce its power consumption when it hits the set temperature? And I highly doubt I'll be able to get 20c in a space this large.

Ultimately this entire endeavour will be decided by my site engineers, but I'd like to understand your personal thoughts for the application of inverter units in a space like this.

Would you recommend it still?

Any responses would be much appreciated.

Sure. The yellow line is the area that is internal that needs to be cooled. The ceiling is 11 feet in that area

The green area is 22 feet ceiling.

Our engineers submitted their proposal which involves a mix of inverter and non-inverter AC but I'm keen to see other thoughts & justifications

Their suggestion is to stick with the Daikins as they have a good relationship with them after having transacted millions of dollars with them.

This post has been edited by pizzaboy: Feb 4 2024, 10:07 AM

Hey thank you for that.
That's a very different layout and suggestion from our engineers.

Do you have any justification for this?

And I'm assuming this is the BTU suggestion yes?

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.

This post has been edited by pizzaboy: Aug 21 2024, 05:41 AM

Nah, it was quite affordable. We had to dig the ground to put the sewerage and foundations anyway, so it wasn't much more to just chuck in a bunch of ceramic tubes. Dehumidifer and ERV, we bought from China so we skipped the middleman. So all in all, I think it cost us an additional RM6,000 only. There's actually a house in Melaka, that has built this.

https://www.cooltek.org/

The ERV and dehumidifier is a more recent addition as we get skin issues from the humidity of the air. But yeah I'll keep you updated.

According to my HVAC fellas, to answer your question, no it's not a waste of money. But it's very use case specific. Large areas like ours, where we have 2,500 sqft of open connected areas, there's no split inverter that can cool down that space, except VRV units. So they said in that case, might as well just use non-inverters.

Also we calculated our panels production which is 14kw/h system, so we make about 2,100KW a month. We definitely do not use 2,100 kwh a month

But for rooms, they still said inverters would be reasonable. But we've oversized our inverters by 0.5hp just for contingency sakes as we sleep in 18c.

As to why we won't use VRV units, it's because we've used them in the past, and they're a massive headache when it comes to servicing. Our servicing bill was RM18,000 a year because the house was quite big and we had the ac on 24/7. Since we're retired now, and downsizing we just don't want any more headaches.

Hey man, how do you tell the temperature is more constant?

For context, wherever I go, I always keep it at 18c, and I run it at full speed. I have never been able to tell when it's an inverter or not an inverter AC.

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.

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.

Perfect. Thank you very much for your input. It's much appreciated and has been supremely helpful.

The entire room is actually hidden away at the darkest spot of the house. So we are surrounded by walls, and absolutely no sun comes in unless we open the bathroom door or master's door.

Sleep = Dark. Everything else = bright was the surrounding principle of this place.


Brilliant. Looks like the HVAC guys were right after all. Thank you for your input!