Passive HouseCould this be the best insulated house in Kent? Conker Conservation were commissioned to undertake the detailed design and contract administration of a detached house in Shepherdswell, near Dover. The client had secured planning permission despite local objections and numerous planning restrictions. Conker reviewed the design and suggested a number of alterations and improvements that would improve energy efficiency and reduce heat loss. The client agreed to go as far as their budget would allow towards achieving the Passivhaus standard. There are more than 7,000 Passivhauses completed across Europe, most being in Austria and Germany. The principle behind Passivhaus design is that energy consumption for heating is low (15W/m2 annum) it can be met largely by the incidental heat gains given off by the occupants and their activities (check description against Passivhaus.org.uk). Any supplementary heating can be provided by warming the ventilation air, no radiators or underfloor heating are needed, even with temperatures down to The house is curved on plan, largely south facing, the ground storey is of cavity wall construction with a 300mm wide fully insulated cavity, giving a U value of 0.1. The upper storey is timber framed using 300mm I studs filled with Warmcel cellulose fibre, giving a U value of 0.14. The roof also uses I studs, being 400mm deep and fully insulated with a U value of 0.10. The ground floor is insulated with 240mm of polystyrene, with a U value of 0.11. Windows are from Geishen in Germany, supplied and installed through the Ecomerchant Ltd in Faversham, www.ecomerchant.co.uk. They are timber framed triple glazed with a centre pane U value of 0.5 and an overall U value of 0.89. When tested for airtightness the testing equipment was stretched to the limit, the initial test sucked the blower out of the front door frame. After re-securing the blower door with tape an air leakage rate of 1.0 air changes per hour (ach) was obtained; the building regulations require a maximum of 10 ach. Whilst this was the best result ever obtained by the air testing firm Airsmart, we expect a minor improvement during the final stages of completion. Achieving this excellent level of airtightness is the result of very careful detailed design, close liaison with the main contractor, Ecolibrium Solutions Ltd, www.ecolibriumsolutions.co.uk and their fastidious approach to the work. The property has a mechanical ventilation system with heat recovery (MVHR), is solar ready (the panels will be installed on the garage which will be constructed shortly), and has a combined rainwater harvesting system and soakaway by CPM Group Ltd, www.concretepipes.co.uk. Roofing and window cills are in zinc, carried out by Whitstable specialist Barry Shotton, tel: 01227 277298. Solar installation and plumbing is by Sustainable Technology Ltd, www.sustainabletechnology.uk.com. Due to planning conditions the house is fitted with a sprinkler system, by Ultrasafe Ltd. We sincerely hope the client will be happy in their new home and will allow us to monitor energy consumption for future publication.  
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