Two prototypes were designed to improve lighting and heating efficiency in buildings. An active intelligent window was developed which reduces energy demand by automatically using external climatic conditions to heat or cool the interior of the building. An optical fibre illuminator (OFI) was investigated that transports solar illumination to improve daylight in a building. The window monitors the internal and external climatic conditions and then reacts automatically to control the building's internal environment: solar heating, ventilation cooling, humidity, insulation and daylight. The window has two main sections: the upper section contains glazing panels enclosing an insulating roller shutter and blinds, the lower section contains a rotary heat exchanger, fans and the intelligent control system and sensors. The window monitors sunlight, light quantity and quality. The whole structure is contained in a polyvinyl chloride (PVC) frame and can be inserted into the structure of the building easily to replace old-style windows. The OFI captures and transmits solar illumination and transfers it to interior rooms. It is designed to be sited on a south-facing roof where light is collected and transmitted via ribbons of plastic optic fibres through ducts to diffusion tools in walls or ceilings of rooms to be illuminated. The window has been incorporated into the design of a school complex in Italy where it provides improved ventilation, cooling and illumination. The OFI is still at an early stage of development but the team identified the main factors determining optical efficiency of collection lenses.