Samsung is good, we just bought the windfree for same reasons and lot cheaper buying direct from Samsung. Check on you tube there is a guy on there does reviews of electrical reviews in pattaya. HIs videos are interesting. Search for samsung windfree AC reviews thailand and should find it. And electrical usage easy to monitor on app with eco mode as well
We just got the Samsung windfree which is really good. The price difference buying directly from Samsung thailand website was massive compared to shops.
Get a Non O from your country even if you are only here for a few weeks. Make it easier to get bank account. No idea what it will be like trying to open one in December. Its already changed a lot since last december till now (more enforcement of existing rules)