Effect of sitting posture on the thermal insulation of modern office chairs

This study experimentally explored the variability in thermal insulation with different sitting postures and a contemporary selection of chair designs. Also, the insulating effect of three different types of facemasks was evaluated. Measurements were made with a thermal manikin seated in a well-controlled climate chamber at three different room temperatures: 20 ± 0.2 °C, 25 ± 0.2 °C and 30 ± 0.2 °C. Two sitting postures were investigated: back in contact with the chair backrest or not, i.e. leaning slightly forwards. The selected chairs had effective thermal insulation around 0.14-0.17 clo when the manikin was seated with the back in contact with the chair backrest, except the applied executive chair, which provided 0.26 clo. On average, leaning forwards reduced the clothing insulation by 0.09 clo. The tested facemasks all provided the same marginal insulation 𝐼_𝑐𝑙𝑢 of 0.05 clo. The measured chair insulation values were well aligned with those from earlier studies. The study confirms that chair insulation is a parameter that should be carefully evaluated and considered when assessing thermal comfort.