You name it, this house has it: an air-source heat pump, a rainwater harvester, central-vacuuming system, triple-glazing and motion-sensitive lighting system. It also features underfloor heating and self-closing loos. The five bedrooms are arranged over three storeys.
Secret bookcase door at the end of the hall - In many new houses, the hallway continuing beyond the door would be an immediate giveaway that there was a door there. In older homes, things have been moved around so much that people would think less about it.