Pipe Insulation Thickness Calculator

Temperature of the refrigerant pipe surface (approximately equal to refrigerant temperature for uninsulated pipe). Suction lines are typically at evaporating temperature.

Temperature of the surrounding air where the pipe is located. Use worst-case design conditions (hottest expected ambient for condensation prevention).

Ambient relative humidity as percentage. Higher humidity means more insulation needed. Design for worst-case: 80-90% in humid climates. Condensation occurs when surface temp is below dew point.

Thermal conductivity of insulation material in BTU-in/hr-ft2-F. Elastomeric foam: 0.27-0.28. Fiberglass: 0.23-0.25. Polyisocyanurate: 0.18-0.20. Lower k = better insulator.

Outside diameter of the copper refrigerant pipe. Common sizes: 3/8" = 0.5" OD, 1/2" = 0.625" OD, 5/8" = 0.75" OD, 7/8" = 1.0" OD, 1-1/8" = 1.25" OD.