n this regard, Humphreys and Nicol evaluated the validity of
comfort theories based on the steady-state endeavours through
several field studies [3,69–71]. Briefly, they stated that the range of
comfort temperatures in naturally ventilated buildings is much wider
than what PMV-PPD models predict (especially in summer).
They stated that there is a discrepancy between the findings from
field studies and the comfort predictions based on the heat
balance model.
Fig. 3 shows that people are comfortable in a wider range of
indoor climates than would have been expected from the heat
exchange models. When Humphreys [69] calculated the PMV
using data from some field studies, he noted that the calculated
PMV differs from the actual mean vote and the PMV almost always
underestimates the actual mean votes. On the other hand, Fanger
[72] suggests that the difference in results arises from “poor data
input”. Here, it is essential that all four environmental factors are
properly measured and that a careful estimate is made of the
activity and clothing. Malama [73] noted that the difference may
arise due to the