Just an update. Ansons offered a Panasonic Conventional ac that has 11.3 eer, surprisingly, it fits the hole and no need for minor works. Ended up buying that instead of the Condura and it's also cheaper. So far, wife's happy with the cooling cap of Panasonic. Hopefully the higher eer (close to inverter eer's) translates to tiny savings the least.

Thanks for the insights, guys. Will probably try the inverter ac soon, when replacing the old one on my parent's house.