OK, no repair, no problem, want to sleep undisturbed. Will buy new aircon.

Perhaps someone knows what size is needed for 25 qm?

What brand, as silent as possible , would you recommend?

Mitsubishi slim line works very good for me.

No noise at all.

Be aware, don't buy Mitsubishi Heavy Industry as they are not of the same quality.

25m² with a normal height ceiling = 12,000 btu. Panasonic also quiet and reportedly reliable.

I've tried them all - forget LG/Samsung and I would go for Daikin 12/13 BTU for 25 sq meters to 30 sq meters

I bought both of our air conditioners at Siam TV, we have had a Mitsubishi for 5 years, quiet, reliable and efficient. We got a Carrier for a spare bedroom about 6 months ago, it also works well and of course the brand is very well known. We have them serviced by the seller, make an appointment and they show up, do the job and don't leave a mess.

Bought a LG a year ago for the bedroom and its been working like a champ. Bought it at Siam TV, the price you see is the price for the unit and installation.

We have 5 Trane, 1, 60,000 (whole house) 8 year old, and 4 under 22,000 for the bedrooms. 1 is 20 year old moved from old house to new build (16 year ago at no charge.) 3 are 16 year. The only breakdown was a electric fan motor gave up the ghost on 1 of the 16 year old units

I can't compare noise level with other manufactors, but for depndabili8ty and the dealer, yearly service (same location 20 years)

they seem hard to beat.