In some of the new standards for thermal environments a certain operative temperature range is given as a requirement for the thermal environment. In other standards the requirement is given as an interval for the PMV-index. This index takes the activity level, clothing, air humidity and the equivalent temperature into account. In this paper it is discussed whether the operative temperature is satisfactory or the equivalent temperature should be used as a better expression because it also takes the air velocity into account. It is shown that the use of the equivalent temperature can save energy during summer conditions but also that it can be necessary to increase the temperature during winter conditions in order to keep the thermal comfort at an acceptable level.