The effective temperature at which fingertips sense thermal effusivity and the bias of measurements at room temperature.

• The effective measurement temperature of fingertip sensing has been derived. • This may serve as a guideline for iso thermal thermal effusivity measurements. • Doing them yet at room temperature causes <7% bias for airy materials, like textile. • Fingertip mimicking methods deviate <19% from fingertip sensing for airy materials. Thermoreceptors in the fingertips sense the temperature drop upon contact with an object and in that way its thermal effusivity. But, at which effective object temperature? That is the question that this article answers by perturbation analysis for slightly temperature dependent thermal properties. How much deviate thermal effusivity measurements at room temperature from fingertip measurements at said effective object temperature? This question is also answered by perturbation analysis. The bias may be up to 7% using nearly isothermal measurement methods and up to around 19% using fingertip-mimicking measurement methods for airy materials like wool. Rewriting the temperature model reveals a felt delay and its dependency on the thermal contact resistance between fingertip and object. [ABSTRACT FROM AUTHOR]