onlok:
my son has got the nose-allergy problem so he can't use air-con. Hence, I use 冷風機(innotec, change ice box every 3 hours)+竹蓆+風扇 for the whole summer till now, not switching on the air con so far, okay 呀.
also, for us couple, just use the 竹蓆+風扇, and a cold shower before sleep. okay 呀, so far no need to use the air-con for sleeping yet.
btw, our flat face the east side, hotter in the morning time.
冷風機 is not suitable in HK, because HK is too humid and 冷風機 increase humidity rather than decrease it as done by air-conditioner. I would suggest you to use air-conditioner instead.