My contractor’s plumber told me that copper is prone to leaking if using compression fittings. If you want to use copper, better to weld. PB is the better alternative to copper when leaking is concerned.

I don’t know the exact installation cost for hot water piping only, but I was quoted RM2800 including hacking & retiling, repositioned cold water pipe to center the final shower system, reposition wirings for storage water heater, install hot water pipe & drain pipe for storage water tank, lowering town plaster ceiling to accommodate storage water tank and installation of storage water tank. All materials inclusive except for storage water tank itself. Additional RM350 if I opt for copper. It’s sounds quite expensive to me compare to prices I read in the internet, but looking at additional scope of works I requested, I think it wasn’t that bad

Can you share me your plumber's contact please?