Then wrap the ducts with duct wrap insulation of R-6 with a vapor retarder facing on the outer side. All joints where sections of insulation meet should have overlapped facings and be tightly sealed ...

then the water lines and the ducts should be insulated. Make sure your contractor checks the ductwork for air leaks before installing the duct insulation. The contractor should then wrap the ducts ...

The Residential Building Code calls for R-8 insulation for these ducts ... plug any air leaks by sealing all the joints with ...

To help mitigate that, some, like this person who posted on Reddit, have turned to bubble wrap as insulation ... Therefore, any air or any temperature making it through the window makes it ...