The sunlighthouse is Austria's contribution to the european program of erecting exemplary "model homes", initiated by the denish manufacturer of roofwindows, VELUX. All "model Homes" are designed to meet a synthesis of energyefficienca, comfort and environmental care at highest possible level. "Sunlighthouse" is a carbon neutral Plus-Energyhouse, at highest levels of indoor health, richly supported with daylight design and erection was scientifically consulted by DBU and IBO. Within the recent project, our department ist doing the longtime-monitoring. From commissioning, via demonstration phase to occupancy phase all relevant criteria of comfort, health and energy-consumption are monitored and analysed. Putputs directly feed into improvements within sunlighthouse and furthermore into further product developments.