Insulation for Up to 100 °C — hot water, condensate, LP steam traces

Heat loss is modest per metre but these systems are HUGE — kilometres of hot-water and condensate pipe. Glass wool wins on cost; elastomeric/PIR rule below ambient.

Valid materials

What survives Up to 100 °C

Material (serves this class)	Max service	λ at 90 °C duty
Stone wool (mineral wool)	640 °C	0.041
Glass wool	450 °C	0.038
Ceramic fibre (RCF / AES blanket)	1200 °C	0.060
Aerogel blanket	650 °C	0.023
Calcium silicate	650 °C	0.056
Expanded perlite	650 °C	0.060
Cellular glass	430 °C	0.047
Microporous (fumed-silica) panels	1000 °C	0.022
Elastomeric foam (FEF)	150 °C	0.040
PIR / PUR rigid foam	140 °C	0.028
E-glass needle mat	550 °C	0.045
Silica needle mat / fabric	1000 °C	0.055

Computed · DN100 at 90 °C, 50 mm

The numbers at this temperature

Material	λ W/m·K	Loss W/m	Surface	Saving €/m·yr	t CO2/m·yr
Stone wool (mineral wool)	0.041	27	24 °C	€110	0.4
Glass wool	0.038	25	24 °C	€110	0.4
Ceramic fibre (RCF / AES blanket)	0.060	39	26 °C	€104	0.4
Aerogel blanket	0.023	15	22 °C	€115	0.4
Calcium silicate	0.056	36	25 °C	€105	0.4
Expanded perlite	0.060	39	26 °C	€104	0.4
Cellular glass	0.047	30	25 °C	€108	0.4
Microporous (fumed-silica) panels	0.022	15	22 °C	€115	0.4
Elastomeric foam (FEF)	0.040	26	24 °C	€110	0.4
PIR / PUR rigid foam	0.028	19	23 °C	€113	0.4
E-glass needle mat	0.045	30	24 °C	€108	0.4
Silica needle mat / fabric	0.055	36	25 °C	€105	0.4

DN100 pipe at 90 °C, 50 mm insulation, per metre of pipe; bare loss 251 W/m. λ at mean temperature; € and CO2 per metre·year at €0.05/kWh, 8000 h, 82% efficiency. Method: ASTM C680 simplified (h=10).

FAQ

Questions on this topic

What insulation is best for below 100 °c?

Shortlist for hot water, condensate, LP steam traces: Glass wool, Stone wool (mineral wool), Elastomeric foam (FEF), PIR / PUR rigid foam. Heat loss is modest per metre but these systems are HUGE — kilometres of hot-water and condensate pipe.

How much heat does a pipe at 90 °C lose?

A bare DN100 pipe at 90 °C loses ≈251 W per metre in still air (ASTM C680 simplified). 50 mm of glass wool cuts that to ≈25 W/m — ≈€110 and 0.40 t CO2 saved per metre·year at €0.05/kWh.