Energy performance is a driving force behind comfortable solutions. But there is also a growing need for comfort which is unrelated to energy-efficiency. Despite rising energy costs, the wealthier parts of the world have experienced significant increases in prosperity in past decades. This increased prosperity means that more and more people have been able to afford levels of comfort which previously were financially unattainable. Something that was a luxury reserved for the very few yesterday is permissible for a great many people today and will be standard for everyone tomorrow – as has happened with the size of window openings and hence the light and transparency of interiors, or with central heating systems. The same is true of the fact that in most parts of the Western world between 1900 and 2000 the number of square metres per person has quadrupled, which has also placed a great deal of pressure on energy consumption. Some of the ways in which floor space is increased are the conservatories, winter gardens and enclosed balconies which can be found in many new residential developments. Such rooms are used not only in the summer as indoor-outdoor space, they are increasingly being used in other seasons as well. They usually do not have complete heating and cooling systems (and are not insulated in the same way as the rest of the residence), but with available Reynaers technology it is possible to improve the wind-tightness and water-tightness to the extent that such rooms can be used nearly all year-round. A last aspect of comfort in the Reynaers systems, besides being maintenance-friendly, is their ease of use. The operation of all systems meets the strictest norms, meaning that very little strength is needed, making it suitable for all users, from elderly to young, with little effort required. And for those who would rather not use any muscle power at all, the sliding doors of the CP 155 and CP 50 systems are available with motors which make it possible to operate these doors literally at the push of a button.