The roof windows were a key consideration in the design. These had to provide sufficient daylight, be seamlessly integrated into the roof-mounted solar panel system, be airtight, aesthetically appealing and also benefit from the police-approved ‘Safe Housing’ label. Two roof windows per home guaranteed the requisite daylight in the rooms immediately below the roof. Thom Grevengoed, says: “In the end, VELUX designed a bespoke roof window; the GGL PK08 2068Q which satisfied all of the project’s requirements. We regularly sat around the table in order to come up with this exclusive product. For example, a modification was required to enable the roof window to be integrated with our chosen GSE mats, which are fitted beneath the solar PV panels. We also paid considerable attention to detail in terms of the 'airtightness' requirement. Naturally, everything had to be seamlessly integrated. The roof windows were equipped with exterior blinds as standard, making a positive contribution to the EPC (Energy Performance Coefficient) calculations."