Daylighting elements in under-roof spaces such as roof windows have always been among the worst elements of the building envelope in terms of heat transmission. New skylights will be developed and tested in alternatives, using new type of materials for their frames. This will be structural material based on hardened polystyrene in full, homogeneous profiles or composites. Such profiles will be developed within the project. The appropriate coating will be found. New skylights with integrated functions will reduce the heat losses to 50 % up to 25 % of usual solutions. The risk of overheating will be reduced significantly and the need for mechanical cooling of under roof spaces will be minimized. The time needed for installation on the building site should be reduced to 50%.