Heat Flow Meter - thermal conductivity testing of insulation materials

HFM Lambda - Heat flow meter

The LINSEIS Heat Flow Meter provides a rapid and easy to use instrument to determine the thermal conductivity properties of low thermal conductivity insulation materials as well as all other materials with a high level of accuracy. The instrument is designed per ASTM C518, JIS A1412, ISO 8301 and DIN 12667. The principle of measurement is to position a sample between a hot and a cold plate and to measure the heat flow. 

System Design

The LINSEIS Heat Flow Meter is a robust and reliable instrument. Its unique design enables highly accurate measurements within minutes. The system provides an excellent long term stability enabling precise long term aging studies. Fast measurement cycles as little as 15 minutes can be achieved, resulting in a high sampling rate. To enable these fast and precise sampling intervals the instrument uses a dual sensor arrangement. An integrated length measurement provides immediate sample thickness data.

Instrument features:

  • Highest precision and accuracy
  • Very robust design
  • Very easy handling
  • Fast sampling (approx. 15min for QC)
  • Automated operation
  • No cooling water required
  • No PC required


Models: HFM 300/1 HFM 300/2 HFM 300/3 HFM 600/1
Temperature Range (Plates): Fixed 0 to 40°C

var. 0 to 100°C

-20 to 75°C

var. -30 to 90°C var. -20 to 70°C
Cooling system: Forced Air Forced Air External Chiller External Chiller
Temperature control (Plate): Peltier Peltier Peltier Peltier
Measurement Data points: 1 15 15 15
Sample size: 305x305x105mm3 305x305x105mm3 305x305x105mm3 600x600x205mm3
Th. resistance measuring range: 0.1 to 8.0m2K/W 0.1 to 8.0m2K/W 0.1 to 8.0m2K/W 0.1 to 8.0m2K/W
Th. conductivity measuring range: 0.001 to
2.5 W/m*K
0.001 to
2.5 W/m*K
0.001 to
2.5 W/m*K
0.001 to
2.5 W/m*K
Reproducability:  0.25% 0.25% 0.25% 0.5%
Accuracy: +/- 1 to 3% +/- 1 to 3% +/- 1 to 3% +/- 1 to 3%
Variable contact pressure 0.25kPa 0.25kPa 0.25kPa 0.25kPa

The Linseis Heat Flow Meter can be operated through the touch screen front panel. Optional software free of charge is available. This state of the powerful software package enables convenient temperature programming, data storage and instrument control. 

Key features:

  • Easy measurement parameter input
  • Measurement data storage and export
  • Report printing, layout can be customized
  • Multi language software versions
  • Instrument monitoring (plate temperature, thermal conductivity results and output signal monitoring)
  • Software help functions
  • Optional user login and data monitoring


Polymers, Organics, Ceramic/Glass/Building Materials, Inorganics


Ceramics, Building Materials and Glass Industry, Automotive / Aviation / Aerospace, Research, Development and Academia, Cosmetics, Pharmaceuticals and Food Industry

Applications Example:

The present measurement clearly demonstrates the outstanding reproducibility of the LINSEIS HFM series. A reproducibility of 0.5% was achieved. The graph displays four measurements of an elastomer foam in the temperature range from 15 to 40°C. The sample was removed and replaced into the instrument after each measurement.


15 Measurement of the IRMM-440certified reference material (Resin bonded glass fiberboard) with a thermal conductivity of 0,03274+-0,00015 at 30°C and 0,03102+-0,00012 at 15°C. The X-Axis shows the temperature gradient.


The graph shows two measurements of the same glass wool specimen at several temperatures. The black line shows the thermal conductivity according the manufacturer information. The X-Axis shows the temperature gradient.