insulating pipes in warm service void

[ajrobb]

I am about to replace 15mm copper water pipes with PEX in a service void. The existing pipes are lagged. However, the void is in the lounge behind the stairs and formed of a single 12.5mm layer of plasterboard. The pipes are on an external wall with 75mm CWI. I think the void will be about the same temperature as the lounge.

Bearing in mind that I'll have to tear down almost the entire void to fit insulation. Is there any point trying to insulate the replacement pipes?

 

[D_Hailsham]

Do you mean domestic hot water or radiator pipes? If DHW then insulting them will reduce losses to the tap. But if CH pipes insulating is not necessary.

Some of the heat will escape through the wall, but the majority will come through the plasterboard into the room and contribute to the heating. It's normally only pipes in unheated spaces - lofts and under the ground floor - which should be insulated.