Glass wool at 150 °C — heat-loss table

λ = 0.042 W/m·K at mean temperature ((150+20)/2 = 85 °C, from the published curve). Pipe losses per metre, four thicknesses, savings vs bare.

Pipe	30 mm W/m	50 mm W/m	80 mm W/m	100 mm W/m	BARE W/m	Surface @50 mm	Saving €/m·yr @50 mm	t CO2/m·yr
DN25	31	24	19	17	136	26 °C	€55	0.20
DN50	45	33	26	23	246	27 °C	€104	0.38
DN80	60	43	32	28	363	27 °C	€156	0.57
DN100	73	51	38	33	467	28 °C	€203	0.74
DN150	100	69	49	42	687	28 °C	€302	1.10
DN200	126	85	60	51	895	28 °C	€395	1.45
DN300	178	118	82	69	1,323	29 °C	€587	2.15

Assumptions: 20 °C ambient, still air (h=10 W/m²·K combined), €0.05/kWh fuel, 8000 h/yr, 82% efficiency, 0.183 kg CO2e/kWh (DESNZ 2024). Flat surfaces at this duty: bare 1,300 W/m² → 101 W/m² at 50 mm (≈€585/m²·yr saved). Method: ASTM C680 simplified — methodology. Your exact case: free calculator.

Context

All materials at 150 °C

Material	λ W/m·K	Loss W/m	Surface	Saving €/m·yr	t CO2/m·yr
Stone wool (mineral wool)	0.044	54	28 °C	€201	0.7
Glass wool	0.042	51	28 °C	€203	0.7
Ceramic fibre (RCF / AES blanket)	0.060	72	31 °C	€193	0.7
Aerogel blanket	0.024	30	25 °C	€213	0.8
Calcium silicate	0.060	71	31 °C	€193	0.7
Expanded perlite	0.064	75	31 °C	€191	0.7
Cellular glass	0.050	61	29 °C	€198	0.7
Microporous (fumed-silica) panels	0.022	28	24 °C	€214	0.8
Elastomeric foam (FEF)	0.040	49	27 °C	€204	0.7
E-glass needle mat	0.045	55	28 °C	€201	0.7
Silica needle mat / fabric	0.055	66	30 °C	€195	0.7

DN100 pipe at 150 °C, 50 mm insulation, per metre of pipe; bare loss 467 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).

Material datasheet: Glass wool → · temperature class: by temperature →

FAQ

Questions on this topic

How much heat does a pipe at 150 °C lose with glass wool?

With 50 mm at 150 °C (λ=0.042 at mean): DN50 loses 33 W/m, DN100 51 W/m, DN200 85 W/m — vs 467 W/m bare for DN100. Full table on this page.

What surface temperature does glass wool give at 150 °C?

≈28 °C with 50 mm on DN100 (20 °C ambient, still air). Personnel-protection targets (≤45–60 °C) may need more thickness — see the 80/100 mm columns.