A novel heated/cooled chair was evaluated for its effect on thermal sensation and comfort. The chair is exceptionally efficient, allowing standalone battery operation over long periods. Its capabilities at providing comfort needed to be established. Twenty-three college students participated in 69 2.25-hour tests. Four heated/cooled chairs were placed in an environmental chamber resembling an office environment. The chamber temperatures were 16°C, 18°C and 29°C. During the tests the subjects had full control of the chair power through a knob located on the chair. The heated/cooled-chair results could be compared to those of conventional mesh and cushion chairs tested in the same three environmental conditions in a previous study, as well as to a thermoelectrically heated and cooled chair. Subjective responses for thermal sensation and comfort were obtained at 15-minute intervals. The results show that the heated/cooled chair strongly influences the subjects’ thermal sensation and improves thermal comfort and perceived air quality. No significant differences were found between men and women. The chair provided comfortable conditions for 92% of the subjects in a range of temperatures from 18°C to 29°C.