How to reduce heating of cold water pipes in the ceiling space?
If you dont want to run a new pipe you will need specific insulation



Notice that this insulation has a shiny outside layer. This acts as a reflection for heat, and usually has a black/dark side on the inside.

The foam/glass wool used to wrap the pipe needs not be anything special, but I am sure there are special ones that locks out heat better.. instead of the conventional one that keeps heat in.. is there a difference? I am not sure.

Look at this insulation- They wrap silver around the pipe and then insulate it. You DONT want to do this.. because this keeps the heat INSIDE the pipe, and the insualtion slows down absorption of coldness form the earth

As commented- it has no difference--inside or outside- it will deflect the heat in both cases... This is open to debate though.



So you are looking for Glass Wool Pipe Insulation with reflective outer shield