Thermal insulation — materials, physics and the numbers (2026)

What thermal insulation is, how it works, the full industrial material families with measured λ ranges — and what it actually saves, computed to ASTM C680 rather than asserted.

How it works

Three heat paths, one job

Heat crosses an insulation layer three ways: conduction through the solid skeleton and the pore gas, radiation across the pores (grows with T³ — why λ rises with temperature), and convection if pores are large enough for gas to circulate. Every insulation material is an arrangement for minimising all three: fibres and cells trap air below its convection threshold; opacifiers block radiation; minimal solid bridges cut conduction. The result is a λ between ~0.020 and ~0.050 W/m·K at ambient — versus ~50 for steel.

The materials

Thermal insulation materials — the industrial set

Material	λ range W/m·K	Max service	Family
Stone wool (mineral wool)	0.036–0.121	640 °C	fibrous
Glass wool	0.033–0.074	450 °C	fibrous
Ceramic fibre (RCF / AES blanket)	0.060–0.220	1200 °C	fibrous
Aerogel blanket	0.020–0.055	650 °C	nanoporous
Calcium silicate	0.055–0.104	650 °C	granular/rigid
Expanded perlite	0.060–0.092	650 °C	granular/rigid
Cellular glass	0.038–0.068	430 °C	cellular
Microporous (fumed-silica) panels	0.022–0.040	1000 °C	nanoporous
Elastomeric foam (FEF)	0.034–0.040	150 °C	cellular
PIR / PUR rigid foam	0.023–0.028	140 °C	cellular
E-glass needle mat	0.045–0.095	550 °C	fibrous
Silica needle mat / fabric	0.055–0.110	1000 °C	fibrous

λ at mean temperature across each material's published curve — full datasheets behind every link. Pick by temperature first: temperature classes →

What it saves

The computed case

A bare DN100 pipe at 180 °C: 575 W/m, continuously. With 50 mm of stone wool: 69 W/m (88% less), surface 30 °C. Annually per metre: ≈4,933 kWh fuel, €247, 0.90 t CO2. Whole-field comparison at this duty:

Material	λ W/m·K	Loss W/m	Surface	Saving €/m·yr	t CO2/m·yr
Stone wool (mineral wool)	0.046	69	30 °C	€247	0.9
Glass wool	0.044	66	30 °C	€248	0.9
Ceramic fibre (RCF / AES blanket)	0.060	88	33 °C	€237	0.9
Aerogel blanket	0.025	39	26 °C	€261	1.0
Calcium silicate	0.062	91	33 °C	€236	0.9
Expanded perlite	0.065	95	34 °C	€234	0.9
Cellular glass	0.052	77	31 °C	€243	0.9
Microporous (fumed-silica) panels	0.022	34	25 °C	€264	1.0
E-glass needle mat	0.045	67	30 °C	€247	0.9
Silica needle mat / fabric	0.055	81	32 °C	€241	0.9

DN100 pipe at 180 °C, 50 mm insulation, per metre of pipe; bare loss 575 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).

Your geometry and prices: free heat-loss calculator → · what the avoided CO2 is worth: Carbon Cost Hub →

Inzonex removable modular insulation on industrial equipment

From the people who publish this data

Components that get opened need covers that come off.

Inzonex makes modular removable insulation — engineered covers with snap-button closures, cores tiered by temperature (needle mat / wired mat / silica), surfaces held at ≤45 °C:

Up to 96% less heat loss from covered components
6× faster maintenance access than standard insulation jackets and metal cladding/boxes — unclips, refits, survives the cycle
Typical payback up to 2 years (hot, frequently-opened gear: 9–11 months)

See Inzonex modular insulation →Get a free savings study

FAQ

Questions on this topic

What is thermal insulation?

Material or assemblies that resist heat flow between a hot and a cold side — by trapping gas in small pores (fibrous and cellular materials), blocking radiation, and minimising solid conduction paths. Performance is expressed as thermal conductivity λ (W/m·K): the lower, the better. Industrial thermal insulation spans roughly 0.020 W/m·K (aerogel) to 0.12 W/m·K (stone wool at 400 °C mean).

What are the main thermal insulation materials?

Three families: FIBROUS (stone/rock wool, glass wool, ceramic fibre, needled glass and silica mats), CELLULAR (cellular glass, PIR/PUR, elastomeric foam) and GRANULAR/RIGID (calcium silicate, expanded perlite), plus nanoporous specials (aerogel blankets, microporous panels). Each material page on this hub carries its temperature-dependent λ and a computed heat-loss table.

How does thermal insulation save energy?

By cutting surface heat loss 85–95%. Computed example (ASTM C680): a bare DN100 pipe at 180 °C loses 575 W per metre; 50 mm of stone wool cuts it to 69 W/m — per metre·year that is ≈4,933 kWh of fuel, €247 and 0.90 t CO2 at €0.05/kWh.

What is the difference between thermal insulation and industrial insulation?

Thermal insulation is the physics and the materials; industrial insulation is their application to process plant — pipes, vessels, valves, boilers — where service temperatures (100–600 °C+), maintenance access and personnel-protection limits (≤45–60 °C surfaces) drive the design rather than building codes.