HFM – Heat Flow Meter

Thermal conductivity meter for testing insulation materials


On point

The LINSEIS Heat Flow Meter provides a rapid and easy to use instrument to determine the thermal conductivity properties of low thermal conductive insulation materials as well as all other materials with a high level of accuracy.

The thermal conductivity instrument design is based on 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.

HFM features:

  • Highest precision and accuracy
  • Very robust design
  • Very easy handling
  • Fast sampling (approx. 15 min for QC)
  • Automated operation
  • Peltier modules for temperature regulation
  • Measurement range extension up to 2.5 W/mK
  • Up to 99 temperature points
  • No PC required

Service and Maintenance
The robust system design and the unique “zero maintenance” peltier heating and cooling cycle ensure a minimum of upholding cost.

Sample Thickness
The instrument has two built in linear potentiometer, offering automated highest precision sample thickness determination. Two heat flux sensors then measure the heat flow, which is precisely defined between the hot and cold plate.

Test Cycles
The double heat flux sensor configuration ensures shortest possible measurement cycles. A typical measurement for most samples can take as little as 15 minutes until the temperature stabilizes.

House isolated

Determination of thermal conductivity with a HFM-Heat Flow Meter of building materials becomes more and more crucial as the demand for insulation materials and energy savings increases

System Design of a HFM

The LINSEIS Heat Flow Meter is a robust and reliable instrument. Its unique design enables highly accurate measurements within minutes. The intelligent peltier heating and cooling technology allows highest precision temperature control, and in addition reduces maintenance and downtimes significantly.

Direction of Heat flow

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. Integrated potentiometers for length measurements (μm resolution) provide immediate sample thickness data.


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All facts on your hand
Model HFM 200 HFM 300 HFM 600
Temperature Range (Plates): 0 to 90°C
-20 up to 90°C
-40 up to 90°C
0 to 90°C
-20 up to 90°C
-35 up to 90°C
-20 to 70°C

Cooling system: External chiller or Thermostat External chiller or thermostat External chiller or thermostat
Temperature control (Plate): Peltier Peltier Peltier
Measurement Data points: up to 100 up to 100 up to 100
Sample size: 200×200 up to 100mm thickness 300×300 up to 100mm thickness 600×600 up to 200mm thickness
Th. resistance measuring range: 0.2 to 8.0 m2k/W, with extension: 0.041 to 8.0 m2K/W 0.2 to 8.0 m2K/W, with extension*:
0.036 to 8.0 m2K/W
0.2 to 8.0 m2K/W, with extension*:
0.036 to 8.0 m2K/W
Th. conductivity measuring range: 0.001 to 0.5 W/m-K, with extension: 0.001 to 2.2W/m∙K 0.001 to 0.5 W/m∙K with extension*:
0.001 to 2.5 W/m∙K
0.001 to 0.5 W/m∙K, with extension*:
0.001 to 2.5 W/m∙K
Reproducability: 0.25%* 0.25%* 0.25%*
Accuracy: +/- 1 up to 3%* +/- 1 up to 3%* +/- 1 up to 3%*
Variable contact pressure: 0 – 25 kPa 0 – 25 kPa 0 – 25 kPa

* The repeatability and accuracy might be limited for thermally low conductive samples


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.

Linseis LFA 500 Software

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


Application example: Elastomer foam

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.

HFM Applikation Elastometerschaum


15 Measurement of the IRMM-440 certified 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.

HFM Applikation Glaswolle

External application

The Application of Building Physics in the Design of Roof Windows (published Energies)

Rigid Polyurethane Foams as External Tank Cryogenic Insulation for Space Launchers (published IOP Conference Series: Materials Science and Engineering)

THERMAL CONDUCTIVITY OF WOODEN FLOORS IN THE CONTEXT OF UNDERFLOOR HEATING SYSTEM APPLICATIONS (published Wood Investigation and Application Department, Wood Technology Institute, Poznan, Poland)



Linseis Produktbroschüre HFM 2019

HFM Product Brochure (PDF)