Thanks for the clarification.

But I think when u used the word 'cooling capacity' above, u r referring to 'cooling efficiency' rite?

Anyway, my existing pipes is the thicker pipe for R410a so not an issue. And the quotation for installation of R410a inverter model is rm200 versus R22 inverter model rm150, so the only concern is the gas refilling cost. 

I'm assuming you are changing from an existing R22 gas aircond installation to a R410A inverter type. You can save money on the piping by just getting Daikins. They are the only brand in the market with R22 gas + inverter combo. Best case scenario is you won't need to change your piping at all. Plus, their compressors are more thermally efficient than Panasonics

Hi, thanks for your recommendation. Does all model of Daikin R22 can use back the old piping? But I assume need some wiring for inverter control right?

Additional note, inverter unit seems less cooling then non-inverter. So if you're those expect very fast cooling, then non-inverter is not for you

U'll see savings IF u set ~>25C above. if u constantly set <22C or below, it is as good as non inverter

Here my actual experience. First aircon is panasonic non inverter 1hp using 8hr for sleep. Bill average rm110. Run  about 8-9yrs before it finally spoil.

Replace a new Panasonic inverter 1.5hp. Same usage. Bill cost me average rm70. Already running 5yrs till now.

First yrs already get back my return compare non inverter. Base on the last time bill and current bill. 5yrs now I already save rm2400. The save Can use for service the aircon many many time.

No matter how many hr using, it still save. Long or short. Sometime I find you guy are very slow to adopt the technology which is already more than 10yrs old. And still undecided it now. 

Guys how many HP air con is recommended for a 300+/- studio?

At least 2.5HP for 300sq studio.
the 300 sq is bout a big size of living room 17feet x 17 feet.

OMG serious?! I was thinking something like 1.5HP would be sufficient...

From a few online calculator. 1hp is enough for your case provided your room is well shaded and no kitchen in it. If not take 1.5.

Seriously I don't think 1HP is enuff for you.
1HP maximum cover around room area bout 10feet x 10 feet.

So your studio is 300 sq or 421 sq?
if 300 sq, u need at least 2.0HP, summore weather is very hot around april/may.
http://aircon.boxpinoy.com/

Only need to take 300sq into consideration, as the remaining (421 - 300) are the toilet and outside gate area.

For a room with 12.4ft x 14.7ft, with 9ft height. How do you calculate that and what HP needed for this?

For a hall, since it's kitchen open concept together with living room. It's 29ft x 14ft, with 9ft high ceiling(includes kitchen). what HP is needed for this?

Am thinking to get inverter since if the aircond HP is big enough then it will save electricity. right? (coz of more start/stop)