Aquatherm Technical Bulletin
Just like other plastic piping on the market Aquatherm piping statements on thermal value and the need to insulate or not, can be confusing, but the one thing we do know is, not using properly installed mechanical insulation on your mechanical systems, will increase your operational cost while contributing to the green house gas (GHG) problem.
Take a look at Aquatherm Technical Bulletin:
It is, therefore, the position of Aquatherm that all piping installations where chilled water is to be carried in the piping or where the surface temperature of the piping is expected to be below the ambient dew point temperature shall be insulated per code.
Of course, there are instances where the insulation thickness can be reduced because of the fact that the PP-R piping is naturally thermally resistant, but those cases need to be evaluated and calculated on an individual basis with the central idea that all chilled water piping needs to be insulated. It also goes without saying that all heated (hot) water systems need to be insulated per code as well.
Bottom line is plastic pipe has only a slightly better thermal value than metal pipe and the only answer is to insulate with mechanical insulation.