Skip to main content

What is Heat Flux?


First we need to know the basics.

What is heat?

Heat is simply the transfer of energy from a higher temperature object to a lower temperature object. For example, if you touch someone’s hand and it is cold you are transferring some of your heat from your hand to theirs. We produce heat (body heat) from calories.

What is flux?

Flux is the process of passing or traveling through a surface or substance.

Heat flux

So what is heat flux?

What is heat flux?

Heat Flux is the transfer of heat through a surface or substance. Usually from a heat source to a heat sink. There are three different of measurable heat fluxes, radiative, convective, and conductive.

As mentioned on, conduction is the transfer of heat energy from one substance to another or within a substance; if you have stood in front of a fireplace or near a campfire, you have felt the heat transfer known as radiation; convection is the transfer of heat energy in a fluid. This type of heating is most commonly seen in the kitchen with a boiling liquid.

What are heat flux units?

A flow of energy per unit of area per unit of time is known as heat flux or thermal flux. It is also known as heat flux density, heat-flow density, or heat flow rate intensity. Watts per square meter (W/m2) are the SI units. It is a vector quantity since it has both a direction and a magnitude.


So how do we measure heat flux?
Heat flux sensors

To measure heat flux we use heat flux sensors. Heat flux sensors are made by connecting thermocouple pairs wired together in series across a thin layer of insulation. This will create a voltage differential between both sides of the insulation. The direction in which the heat is flowing is measurable by the positive or negative readings from the lead wires.

HuksefluxUSA sensors

We offer a variety of heat flux sensors.

Latest Articles

Stay up to date with the industry.


InterSolar North America 2023

InterSolar North America 2023 February 14-16, 2023 Long Beach, CA Intersolar North America and Energy…
Hukseflux Headquarters

Hukseflux Thermal Sensors B.V. Annual Sales Meeting

Hukseflux Thermal Sensors B.V. Annual Sales Meeting October 17 – 19, 2022 Delft, The Netherlands…

Best Pyranometer 2022 — a Pyranometer Guide

Best Pyranometer 2022 — a Pyranometer Guide: Next level instruments in every class at the…

The new ISO 9060:2018 standard. Do your pyranometers comply?

PV monitoring and meteorological industries prepare for revised pyranometer standard ISO 9060:2018 Do your instruments…