Temperature and productivity
Several studies have been conducted to quantify the link between operative temperature and productivity. However, it is difficult to devise reliable methods to realise this type of research. One of the more commonly cited studies of the link between air temperature and employee performance indicates that office workers' productivity increases at temperatures of up to 21-22 °C, but decreases by about 2% per degree of further increase.
That said, the ideal productivity temperature is not necessarily the same as the one perceived as providing optimal comfort.
Source: Seppänen et al. 2006