HFP03 specifications:
Nominal Sensitivity 500 μV/Wm2
Nominal Resistance 18 Ω
Temperature range -30 - +70 °C
Sensor thermal resistance < 6.25 10-3 km2/W
Range -2000 - +2000 W/m2
Temperature dependence < 0.1 %/°C
Calibration trace ability NPL, ISO 8302 / ASTM C177
Expected typical accuracy (12 hr totals) within +5%/-15% in most common soil, within +5%/-5% on walls
Figure 1 HFP03 heat flux plate dimensions:
(1) sensor area, (2) guard of ceramics-plastic composite, (3) cable, standard length 5 m.
All dimensions are in mm.

HFP03 is an ultra sensitive sensor for heatflux measurement of small heat fluxes through soil, walls and building envelopes. By using a ceramics-plastic composite body the total thermal resistance is kept small.

A nice clear print of the original product brochure.


HFP03 serves to measure the heat that flows through the object in which it is incorporated or on which it is mounted.

HFP03 has been built specifically for applications where one needs to detect small flux levels, in the order of less than 10 Wm-2, for instance in geothermal applications.

The actual sensor in HFP03 is a thermopile. This thermopile measures the differential temperature across the ceramics-plastic composite body of HFP03. Working completely passive, HFP03 generates a small output voltage proportional to the local heat flux.

Using HFP03 is easy. For readout one only needs an accurate voltmeter that works in the millivolt range. To calculate the heat flux, the voltage must be divided by the calibration constant; a constant that is supplied with each individual instrument. HFP03 is weatherproof. It complies with the CE directives.

Traceability of calibration is to the "guarded hot plate" of National Physical Laboratory (NPL) of the UK, according to ISO 8302 and ASTM C177.

In case a sensitive measurement is not needed the model HFP01 should be considered.

For employing HFP03, the HFP01 manual can be used; a dedicated appendix is added. The main differences are dimensions and sensitivity.


  • Additional cable length x metres (add to 5m)
  • AC100 amplifier
  • LI 18 hand held readout.

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