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Enabling better global research outcomes in soil, plant & environmental monitoring.

HFP01 Heat Flux Plate

The HFP01 heat flux plate offers a solution for measuring heat fluxes. HFP01 is the world’s most popular heat flux sensor for heat flux measurement in soil as well as through walls and building envelopes. By using a ceramic-plastic composite body the total thermal resistance is kept small.

Suggested use

  • meteorology
  • building physics
  • H-value and R-value determination
  • building climate control


The HFP01 is available in a preconfigured IoT (Internet of Things) setup for continuous real-time monitoring of heat transfer, thermal resistance and thermal dynamics.

HFP01 serves to measure the heat that flows through the object in which it is incorporated or on which it is mounted. The actual sensor in HFP01 is a thermopile. This thermopile measures the differential temperature across the ceramic-plastic composite body of HFP01. The HFP01 is completely passive, generating a small output voltage proportional to the local heat flux.

Using HFP01 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 sensitivity; a constant that is supplied with each individual instrument.

HFP01 can be used for in-situ measurement of building envelope thermal resistance (R-value) and thermal transmittance (H-value) according to ISO 9869, ASTM C1046 and ASTM 1155 standards.

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

A typical measurement location is equipped with 2 sensors for good spatial averaging. If necessary two sensors can be put in series, creating a single output signal.

 HFP01 Specifications

Nominal sensitivity 50 µV/Wm²
Temperature range -30 to +70°C
Range -2000 to +2000 W/m²
Sensor thermal resistance < 6.25 10-3 Km²/W
Calibration traceability NPL, ISO 8302 / ASTM C177
Expected typical accuracy (12 hr totals) within +5%/-15% in most common soil, within +5%/-5% on walls