, we have interpreted “health and wellbeing” to include social, psychological and physical factors. It is also about more than just a home, but also about community. Physical health can be described as the absence of disease, as well as optimal functioning of our body. Mental health is about much more than just the absence of mental illness: it encompasses positive issues such as peace of mind, contentment, confidence and social connection. Social wellbeing is determined by the strength of an individual’s relationships, and the way in which they function within their community. Light A great example of how sophisticated the thinking has become is a look at lighting. In Neutra’s day (and in the California climate) you couldn’t have enough natural light. But we have learned that with windows, you can have too much of a good thing; houses can overheat in summer, freeze in winter without lots of mechanical heating and cooling. Windows are not just glazing, but more complex: Windows are ‘machines’, in the sense that they combine multiple properties: they should be considered not just as transparent sections of wall, but as important multi-functional elements of the home. Good window design can enhance occupant wellbeing, both physically and psychologically. However, there are a number of common pitfalls which do quite the opposite. Inappropriate glazing design can impact privacy, furniture layouts, amount of solar gain and heat loss. Internal Air Quality This is much more complicated than it was in Neutra’s day (and California’s climate) where you opened windows for fresh air. In fact, it is much more complicated than it was when we started writing about it on TreeHugger, when we stressed tuning windows, cross ventilation and living without air conditioning. We are also living more closely together and have learned more about the dangers of particulates and other air pollutants outside our doors. To save energy we have tightened up our homes, and many of us are living in smaller spaces. However, it is possible to provide sufficient clean, cool, outside air without allowing the ingress of external pollutants, whilst at the same time providing an adequate air change rate to remove these various pollutants. One major challenge we face in the UK is that of balancing the need for more airtight, energy efficient houses with the need for adequate ventilation. We need to ensure that new homes are not only energy efficient, but also provide optimal ventilation rates for good internal air quality. In many parts of many cities, mechanical ventilation and air purification is becoming a necessity because of air pollution. All the more reason to get rid of diesels and electrify our transport systems as soon as possible. Thermal Comfort © UKGBC This is perhaps where the biggest changes have to happen, and soon. For years, the worry in northern climes was keeping warm; more and more, over-heating is becoming a problem. In recent years, we have seen a marked rise in the incidence of overheating, particularly in the new build sector. As the frequency and severity of heatwaves is predicted to increase due to climatic changes, addressing this issue is vitally important. Although most evidence on the impacts of overheating on health is based on outdoor temperatures, with less information regarding safe indoor temperatures. But even this UKGBC report does not get into detail about what comfort actually is, and how it is much more than just an issue of regulating temperature. Moisture Moisture in our homes is generated by activities such as cooking, drying, washing, bathing, and breathing. It is important to control moisture levels because too much moisture in homes can increase growth of bacteria, house dust mites, and mould, all of which represent health risks. Furthermore, dampness could also cause degradation of materials, further polluting the air in buildings. All of these can result in problems with respiratory systems, for example infections or exacerbation of asthma. It used to be that the biggest problem related to moisture was having too