As a engineer, we can calculate the required thickness required for copper pipe insulation.

Assuming standard Air conditioning operation with an ambient temperature of 27 degree Celsius & 77% RH in the room, the requirement for insulation thickness would be minimally 10.5 mm to 12.6 mm for various copper pipe sizes. This translate to 1/2 inch thick insulation which is the current market practice.

So its not free upgrade of material from 3/8 inch to 1/2 inch, it should be standard offer for all AC models.

 

P.S. If you are in cold country with humidity that is lower, you can use 3/8 inch insulation. Singapore weather is just too hot! So overseas branded insulation doesn’t mean its suitable for Singapore climate. =)