Stone wool vs Glass wool

Two mineral wools, one decision: temperature. Below ~250 °C glass wool is cheaper for the same job; above it, glass wool runs out of service limit and stone wool is the only wool left standing.

Specification

Side by side

	Stone wool (mineral wool)	Glass wool
Max service	640 °C	450 °C
Density	80–150	24–80
Standards	EN 14303 · ASTM C547 (pipe) / C592 (wired mat) / C612 (board)	EN 14303 · ASTM C547 / C553
Forms	wired mats, pipe sections, slabs, loose wool; the workhorse core of removable covers up to ~600 °C	pipe sections, rolls, lamella mats — lighter and cheaper than stone wool

Computed equivalence · DN100

Thickness for the SAME heat loss

Duty	λ Stone wool	λ Glass wool	Stone wool thickness for EQUAL loss to 50 mm of Glass wool
100 °C	0.041	0.038	55 mm vs 50 mm
250 °C	0.052	0.050	54 mm vs 50 mm
400 °C	0.067	0.064	52 mm vs 50 mm

Bisection on the cylindrical conduction equation; λ at mean temperature per each material's published curve. Full per-material tables: Stone wool · Glass wool.

The whole field at this duty

All materials, DN100 at 100 °C

Material	λ W/m·K	Loss W/m	Surface	Saving €/m·yr	t CO2/m·yr
Stone wool (mineral wool)	0.041	31	25 °C	€125	0.5
Glass wool	0.038	29	24 °C	€126	0.5
Ceramic fibre (RCF / AES blanket)	0.060	44	27 °C	€119	0.4
Aerogel blanket	0.023	18	23 °C	€131	0.5
Calcium silicate	0.056	42	26 °C	€120	0.4
Expanded perlite	0.061	45	27 °C	€118	0.4
Cellular glass	0.047	35	25 °C	€123	0.4
Microporous (fumed-silica) panels	0.022	17	23 °C	€132	0.5
Elastomeric foam (FEF)	0.040	30	24 °C	€125	0.5
PIR / PUR rigid foam	0.028	21	23 °C	€130	0.5
E-glass needle mat	0.045	34	25 °C	€124	0.5
Silica needle mat / fabric	0.055	41	26 °C	€120	0.4

DN100 pipe at 100 °C, 50 mm insulation, per metre of pipe; bare loss 287 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

Is stone wool better than glass wool?

Two mineral wools, one decision: temperature. Below ~250 °C glass wool is cheaper for the same job; above it, glass wool runs out of service limit and stone wool is the only wool left standing.

How much thinner can stone wool be than glass wool?

At 100 °C duty, 55 mm of stone wool matches 50 mm of glass wool (computed for a DN100 pipe, ASTM C680 simplified). The ratio shifts with temperature because both λ curves rise at different rates.