What gains from heavily insulated exterior ASHP flow / return pipes?

[Mr Gus]

I'm curious.
Most domestic jobs have exterior units with exposed flow & return creeping around / up the domecile.
How does a decent wedge of exterior insulation (under which the flow return are hidden) affect efficiency?

Anyone seen anything to compare an insulated hidden pipework scenario versus a regular jobby?

[Stinsy]

I've never seen a set of feed/return pipes that are not insulated!

[Mr Gus]

Nah, stinsy you misread me..

I'm aware (as are you) there is a standard sleeve of insulation for pipe runs on domestic installs of ASHP.

I'm referring to slab insulation such as a rain fascia & 100mm of PIR covering it & pinning it to the house wall, or exterior modernisation with extruded insulation & render, or boxing in anything running through a loft with a long run of coffin type slab insulation to assist.

That compared to the standard sleeve, or in addition.

[Stinsy]

I get you now...

The sleeve does look very thin. Enclosing the pipes in a "box" created out of 50mm Celotex (or whatever), then enclosed in decorative timber/uPVC would no-doubt be beneficial depending on the length of the run.

How beneficial? Well that depends!

[Mr Gus]

There must be some detail from the likes of Saint-Gobain (Celotex) out there somewhere.

Put it on the "to find" list.

[spread-tee]

You could work out the heat losses for various thicknesses of insulation if you also know the pipe temps and the air temps and the areas of exposed pipery involved. Most exterior pipe runs should be kept as short as practical and given the areas would not be very large the energy lost would also be small-ish.
You wouldn't want to pay a professional installer extra to custom build a pipe enclosure as it wouldn't be cost effective, as a DIY project though, why not?

Desp