Shayan,

The thermal resistance of clothing is somewhat independent of environment, that is to say that the resistance (thermal and evaporative) are related to the amount of dry heat or evaporation that can pass through the clothing (analogous to Ohm's law). Testing for the thermal and evaporative resistances can be done using a sweating hot plate (for textiles) or using a sweating thermal manikin (for full ensembles). There are some standards for these tests (i.e., ASTM F1291-16 and F2370-16). These values can be used to model the clothing affects on the human for any environmental condition (the resistances don't change per se). However, knowing the interplay between the human, environment, and complexities of the clothing (e.g., effects from moisture, air movement, solar) is the tricky part. Collectively these can give you an idea of change in thermal statuses (e.g., core or skin temperature rise/fall).

Thermal comfort on the other hand is trickier still, as it includes subjectivity....

I would suggest checking out some of the papers related to modeling thermal physiological effects that focus on clothing. We have a handful from my group that look at physiological effects (e.g., Potter et al., 2017) but some of the more widely recognized works that address thermal comfort could be helpful also (Fiala et al., 1999 or 2001).

Hope that helps.

Best regards,

Adam

Questionnaires is one way but it is also possible to use infrared camera and estimate the clothes resistance.

You can also use a seasonal based value for your evaluation.

This paper could be useful for you:

"Investigating Occupancy-Driven Air-Conditioning Control Based on Thermal Comfort Level"

https://ascelibrary.org/doi/abs/10.1061/%28ASCE%29AE.1943-5568.0000295