Drill hot water supply line holes in joists larger for insulation?

[Doug Henningsen]

This is for a bath addition in an existing house using PEX pipe. Is there any reason I shouldn't drill joists larger for the hot water supply for pipe insulation vs run insulation only between joists? Naturally, this assumes space allows and the holes don't harm the structural integrity of a joist.

 

[John Gayewski]

You should drill holes big enough for the insulation.