Does outer size matters?
I don't think so. I bought Viola 1.5 ton about a month ago. It's outer is huge compared other gree ACs and other brand ACs.
They claim the EER of 4.0 which is bullshit. Calculating from their own specsheet 5275/1620 = 3.25
Outer sizes of all the ACs at my home
1.5 ton Gree Viola VITH
36x14x28=14,112 cubic inches
1.5 ton Gree CITH1S (Bought last year)
33x12x24=9504 cubic inches
1.5 ton non-inverter Haier (8 years old)
31x10x22=6820 cubic inches
1.0 ton non-inverter Orient (15 years old)
31x10x22=6820 cubic inches
So in terms of volume Viola is more than twice the size of Haier but viola consumes more power on full load compared to Haier and they both take same of amount of time to cool the room down.
Operating outside temp for all GREE ACs is 43C while Haier claims 52C.
So I am wondering why should one buy GREE china instead of Haier china. If you wan't to spend good money then I recommend go for LG instead of GREE, or save your money and buy Haier or Orient.