Insulation ~ Polyisocyanurate

Also know as PIR. Polyisocyanurate is essential a stronger more fire retardant development of Polyurethane. As may be expected it shares many of the characteristics of Polyurethane.


Usually produced as a foam panel insulation, PIR foam panels coated with aluminium are used for the prefabrication of ducts and flues commonly used in heating and cooling systems.


  • Manufactured from petrochemicals so not sustainable and toxic when burnt.
  • High embodied energy.
  • Low k-value – excellent insulator.
  • Moisture & fire resistant.

Usually installed as a foam, Polyisocyanurate has a thermal conductivity or K value of 0.023 W/m.K.
(Watts per meter Kelvin ~ a lower value is a better result)

Per meter costs are difficult to derive as Polyisocyanurate is usually supplied as an all-in service including installation. Typically, it will cost 4 to 5 times more than mainstream alternatives such as mineral wool with a total cost of £2-3,000 for an average UK home.