What building services are necessary for a Passivhaus? This half-day session explores the different services required in true low energy buildings. In these buildings, the heat requirement is usually smaller than the other loads such as hot water. One of the reasons for this, other than the fabric first approach, is the adoption of mechanical ventilation with heat recovery (MVHR) systems. These mechanical ventilation systems need to be integrated into the building for successful operation, and we look at the necessary components, how they should best be installed, their space requirements, and where the supply and extract ducts need to be terminated. The maintenance access requirements (for filter changes) are considered. We touch on commissioning and how this needs to be carried out. There is a small group exercise of finding suitable locations and spaces for the equipment on a simple plan, all from the point of view of a non-specialist.
The second part of the session looks at how the choice of fuel for heating and hot water system can be different from conventional buildings: the Passivhaus requirement for heating systems is to produce a continuous trickle of heat, rather than a conventional system switched on and off by a time switch. The design of hot water systems can be improved to minimize losses, using radial plumbing in small diameter pipes, and there is a short group exercise on this. The definition of primary energy is explained and how to pass the Passivhaus requirements for this, in particular the effect of fuel choice and the difficulties communal heating systems can bring.