"Pipe insulation prevents liquid contents from significantly changing temperature in transit."
The Insulated Liquid Pipe is an item used to transfer Liquids in Oxygen Not Included. It is better than Liquid Pipe in that it attempts to maintains the temperature of the liquid being transferred.
The Insulated Liquid Pipe is in the third tier of Research in Improved Plumbing. To unlock it, Duplicants will need to learn Plumbing and Filtration.