Therequired cooling capacity for a room air conditioner depends on the size of the room being cooled -- room air conditioners generally have cooling capacities that range from 5,500 Btu per hour to 14,000 Btu per hour. A common rating term for air conditioning size is the "ton," which is 12,000 Btu per hour. Proper sizing is very important for TheSpruce / Letícia Almeida. Best for: Cooling a single room to a small home A window air conditioner is technically called a "unitary" air-conditioning system and consists of a self-contained air-conditioning unit that is placed in a window or, less commonly, through a hole in an exterior wall. A window air conditioner contains all the refrigeration components in one compact box. Amazoncom: Split-System Air Conditioners - Split-System Air Thefirst and most evident difference to note is the size. A split unit has two parts - the compressor and condenser are installed outdoors, and the evaporative portion of the unit is what you have inside the house. On the other hand, a window AC contains the compressor, condenser and evaporative sections all in one unit. Althoughair conditioning units are generally subdivided into a number of categories, including window, split and whole house/building units, they still work the same, with the compressor, condense SplitAir Conditioner. A split-AC is like a window AC on steroids. They offer the same room/single space cooling that window AC does, but at a higher capacity. They also operate at a high-efficiency, as high as 25 SEER. That helps you get a good ROI from energy savings in the long run. However, with such advantages come increased costs and Oneof the most energy-efficient air conditioners in its class is the Lloyd 1.5-ton 5-Star Inverter Split AC. While using less power, it provides great cooling performance. Best budget - LG 1.5 Inthe table below, you will find above-average energy-efficient air conditioner and heater window units. The #2 LG LW1216HR with an extremely high EER rating of 11.3 is the most energy-efficient window AC with a heater. It requires only a bit more than 1000W to produce 12,000 BTU of cooling output. KeystoneKSTAW05CE is a capable 5000 BTU air conditioner that consumes less energy than most — and offers some almost-smart features. This eco-friendly window AC unit has lower energy consumption than any other air conditioners on my list, with an EER rating of 12.1. LG- 1,000 Sq. Ft. 18,000 BTU Smart Window Air Conditioner - White. Model: LW1822IVSM. SKU: 6542240. (21 reviews) " And this only one unit enough to cool down the whole 2 bedroom apartment". See all customer reviews. Product Description. The LG Dual Inverter air conditioners are the best in cooling innovation. w8dTweo.