Small prefab Passive House built in just 10 days
We've seen the Passive House sustainability marque awarded to plenty of big flashy home builds. A project in Australia, however, has shown that a certified Passive House needn't be either of those things. Castlemaine Passivhaus is covers just 39 sq m (419 sq ft) and took only 10 days to build.
Passive House certification is awarded to houses that demonstrate highly efficient energy performance. The standard focuses in particular on a building's heating and cooling system, air tightness and approach to ventilation. Not only does certification provide affirmation of a building's sustainability credentials, but large buildings in particular can benefit from the operational cost savings of measures taken to achieve certification.
Designed by Australian architects Carbonlite, Castlemaine Passivhaus shows the Passive House marque is not just reserved for large expensive homes. Carbonlite, which specializes in creating sustainable prefab homes, prefabricated the building's sections off-site over the course of about five days.
The sections were delivered to the site and on the same day the exterior was erected and the building made wind and watertight. The remainder of the house was fitted out over the course of the next 10 days, after which the it was possible for the residents to move in.
The house has a mono pitch roof with an overhang that provides shade for the building and helps to minimize overheating in the summer. The building has a wooden frame with wool and wood fiber insulation. This gives the exterior a U-value of 0.261 W per sq m, contributing to what the Passive House Academy describes as the building's "excellent thermal insulation."
The annual heating demand for the building is calculated at 6 kWh per sq m (0.6 kWh/sq ft) and is met using a Sanden air-to-water heat pump. The building's ventilation, meanwhile, is managed by a Lunos system, with which the Passive House Academy says the building can still deliver a high air tightness performance of "less than 0.6 air changes per hour."
The total annual heating, electricity and hot water demands for the house come in at about 115 kWh/sq m (11 kWh/sq ft). Photovoltaic panels are used to meet some of the electricity demand, whilst a 4,000 liter (just over 1,000 US gallons) tank is used to collect rainwater for use where clean, treated water is not necessary.
Castlemaine Passivhaus was constructed and completed in October 2014. The video below is a time-lapse of the building being erected.