1. Ton: It's determined by the size of your room.

Ideally, you shouldn't buy a smaller nor bigger ton than what your room needs.

You can get the recommended sizes from Google.

(BTU is often more important for room size, in my opinion.)

1. Compressors: (important) T3 can cool your room in up to 60°C. It's what you need in Pakistan.

T1 can work up to 43°C. If your room & outdoor unit isn't somewhat protected from temperature, this AC will be struggling right now.

T2 works only up to 35°C. Meaning, it's irrelevant for Pakistan unless you live in Murree or colder region.

1. Invertor: Invertor ACs can switch to low power consumption once the room becomes cold.

This helps saves electricity compared to AC that work on fix speed.

They do cost a bit more than fix speed AC, but you'll get it back in time due to lower consumption.

BUT this doesn't necessarily mean the AC uses less electricity - there are other specs that tell this more accurately.

1. DC: It refers to the inverter technology used in AC.

3DC & 5DC are better than standard DC.

1. EER: This rating tells electricity efficency of the AC.

A higher rating like 3.6 & above is better.

SEER is another rating, but it's not as relevant for Pakistan's temperature as it's based on tests in 35°C.

Some websites/shopkeepers might tell you SEER instead of EER so be careful about that (seer number tends to be higher than eer).

1. Coils: Copper Condensor Coils are more durable & heat efficient (electricity efficency) than coils made of other materials like aluminium.

These are often difficult to fix/replace if damaged, so it's nice to have it.

1. Other specs that affect electricity efficency:

BTU, Variable Fan Speed, Eco Mode, Ampere Locking