On the international level ISO (International Organization for Standardization, ISO EN 7730), CEN (European Committee for Standardization, EN15251, EN13779) and ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers, Standard 55, 62.1 and 62.2) are writing standards related to the indoor environment. This presentation will focus on the development of standards for the indoor thermal environment and indoor air quality. In the future, recommendations for acceptable indoor environments will be specified as classes. This allows for national differences in the requirements and also for designing buildings for different quality levels. This will require a better dialogue between the client (builder, owner) and the designer. It is also being discussed how people can adapt to accept higher indoor temperatures during summer in naturally ventilated (free running) buildings. Several of these standards have been developed mainly by experts from Europe, North America and Japan, thus guaranteeing a worldwide basis. Are there, however, special considerations related to other parts of the world (lifestyle, outdoor climate, and economy), which are not dealt with in these standards and which will require revision? Critical issues such as adaptation, effect of increased air velocity, humidity, type of indoor pollutant sources etc. are still being discussed, but in general these standards can be used worldwide.

The paper presents an update on today’s requirement for a healthy and comfortable environment. The paper will mainly be dealing with the indoor thermal environment and air quality. Several standards and guidelines are specifying requirements related to comfort and to health; but the productivity of people is not taken into account. Recent studies showing that comfortable room temperatures, increased ventilation above normal recommendation, reduction of indoor pollution sources and more effective ventilation increases the performance of people. The results indicate increase of productivity of 5-10 %. Also based on the laboratory studies a 10 % increase in dissatisfaction decreases the productivity with around 1%.

The paper shows that for well-designed buildings these types of system are capable of providing a comfortable indoor climate both in summer and in winter in different climatic zones. Various control concepts and corresponding energy performance are presented. To remove latent heat, these systems may be combined with an air system. This air system can, however, be scaled down with the benefit of improved comfort (noise, draught) compared to full air-conditioning. An added benefit can be reduced building height due to the elimination of suspended ceilings. Finally, surface heating and cooling systems use water at a temperature close to room temperature. This increases the possibility of using renewable energy sources and increasing the efficiency of boilers, heat pumps and refrigeration machines.

Fanger (1982), Fanger and Langkilde (1975), and Nevins et al. (1966) used equal numbers of male and female subjects, so comfort conditions for the two sexes can be compared. The experiments show that men and women prefer almost the same thermal environments. Women’s skin temperature and evaporative loss are slightly lower than those for men, and this balances the somewhat lower metabolism of women. The reason that women often prefer higher ambient temperatures than men may be partly explained by the lighter clothing normally worn by women.

First, the primary reason is that we are overcooling buildings in summer, using enormous amounts of energy, and creating uncomfortably cold conditions for everyone. A study at Lawrence Berkeley National Laboratory found that average temperatures in office buildings in the U.S. are colder in the summer than in the winter (exactly the opposite of what they should be), and are actually lower than the minimums recommended by the standards. Existing international standards like ISO EN7730, EN15251 and ASHRAE 55 are based on the same basic studies described above. These standards do not specify different room temperatures for women and men when doing the same work and dressed in similar clothing. Contrary to what has been suggested, these standards are not devised exclusively for men. They are based on extensive laboratory studies of both men and women wearing the same clothing, engaged in the same activity, and exposed to a wide variety of thermal conditions (air temperature, surface temperature, humidity and air movement). Metabolic heat production was simply a proxy for the kind of activity. And while it is one of many variables used in an empirical formula, it is not an input to a heat balance equation, as one might find in a thermo-physiological model (which exists, but was not the basis for the standards). The primary reason is that we are overcooling buildings in summer, using enormous amounts of energy, and creating uncomfortably cold conditions for everyone.

The present talk provides an overview and discusses the criteria used for specifying required ventilation rates in international standards like ASHRAE 62.1, ASHRAE 62.2, EN15251 and ISO 17772. The concept for estimating the required ventilation rate to obtain an acceptable indoor air quality is somewhat similar in the standards; but do result in quite different levels of ventilation. Increased ventilation rates will result in increased energy use. To reduce the ventilation rate the most effective way is to reduce the sources (low emitting materials, filtration of outside air). The talk will also present and discuss other ways to reduce energy use for ventilation by means of natural ventilation, improved ventilation effectiveness, demand controlled ventilation, use of air cleaning, personalized ventilation and heat recovery.

Technologies alone do not necessarily guarantee low energy buildings. Occupant behavior plays an essential role in the design and operation of buildings, but it is quite often oversimplified. Occupant behavior refers to an occupant’s movement and responses to discomfort, when his/her comfort needs are not met. Occupant behavior varies with time, space, individual, and is influenced by social context. It is stochastic, complex, and multidisciplinary. Having a better understanding and modeling of occupant behavior in buildings can improve the accuracy of building simulations and guide the design and operation of buildings. This talk highlights related behavior research at various institutes.

Many studies show large individual difference regarding the preferred indoor climate (temperature, air velocity, ventilation). There are many other diversity factors like sex, race, age, culture, etc. that can have a significant influence on the preferred and/or accepted conditions for the indoor environment. Can we take such influence into account when designing buildings and building service systems? Recently the international media like in USA, Canada, UK, Denmark, Germany etc. has been discussing the issue of differences between men and women regarding thermal comfort and the preferred room temperature. Experiments show that men and women prefer almost the same thermal environments. Women’s skin temperature and evaporative loss are slightly lower than those for men, and this balances the somewhat lower metabolism of women. The reason that women often prefer higher ambient temperatures than men may be partly explained by the lighter clothing normally worn by women. This presentation will provide an overview of existing knowledge and discuss related issues.