Working with Graham Drummond of Passivhaus Associates we developed plans for the first of our certified ‘Passivhaus’ developments. Restricted by a very tight and sloping site, this tiny house project was nonetheless completed on time and budget in October 2011. The ‘official’ Passivhaus certificate was received from Warm Associates in Plymouth who are our chosen Certifiers.
The building is extremely well insulated with ‘U’ values generally of around 0.08 W/m2K, and installed ‘U’ values of 0.85 W/m2K for the windows which feature different glazing between North and South elevations to optimise performance. The final air pressure test confirmed an airtightness of 0.28 air changes per hour, well within the 0.6 ach required for the standard and 25 times better than the current building regulations. Whilst a great deal of attention has been paid to the energy side of things, we have also taken trouble to ensure that the building is largely one made of natural materials, the whole timber frame is of untreated timber, and we have avoided the worst materials in terms of toxicity and risks to human health.