depends on how many hrs you use air-cond. if you use more than 5 hrs i would suggest you to buy inverter air-cond. why should we buy the inverter one ? i think that's slightly higher in price.... and i think better grab the normal model in term of save cost Hmmm.... Inverter one can save electric mah.....higher in purchasing price....but when we use it frequently can get the cheaper electric bill, if count it can save alot tho We use the AC for long term...( normally more than 5 years )