This was an old Victorian brick barn formerly used for storing cattle feed. The planning was gained on the basis of the job being an ecological conversion, particularly as it is in an Area of Outstanding Natural Beauty. The client was keen to see an energy efficient building designed to be delivered in commercially viable budgetary constraints. Ecotecture highlighted the Passivhaus standard as the most cost effective means of reducing their reliance on fossil fuels. Balancing the realities of achieving a Passivhaus certified building against increased construction costs, particularly relating to conversion of existing structures; we found a compromise in the form of the AECB Silver Standard. Whilst this building hasn’t been certified to meet the standard, we feel confident that the end result is certainly a good way towards it.
Maria Hawton-Mead of Hawton Mead Sustainable Design provided the Passivhaus Planning Package calculations. Initial calculations showed the building achieving an annual heat and cooling demand of 24Kwh/m2/annum. To achieve this level of energy efficiency, we had to address the thermal bridging issues which are inherent in a conversion of this nature. The calculated u-values from PHPP achieved 0.14/Wm2K on the walls on the roof and 0.1/Wm2K on the floor construction. Psi values were not calculated for inclusion within the PHPP as it was not considered financially viable, good practice was included when developing the construction details for low thermal bridging and PHPP was developed using the typical thermal bridging allowance.
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Conversion, Passivhaus principles, Sussex, Timberframe