Defining the Energy Efficiency Design Envelope for Regional Scottish Passivhaus Dwellings

The aim of this research is to achieve regional solutions to Passivhaus (PH) in Scotland by quantifying the effects of varying key architectural parameters on the energy performance of three prototype house typologies across the different climate data regions. It uses PHPP to generate weather optimisation graphs for glazing area, but expands the variables to include; orientation, typology and roof form. It investigates; detached, semi-detached and mid-terrace housing typologies, altering a number of architectural variables in each case. A four bedroom prototype house design is used based on passive solar principles and specified to comply with a space heating energy demand of under 15 kWh/(m²a) in four Scottish climates and a heating load of under 10 W/m² in two further climate regions. The study investigates the effects on the Specific Space Heat Demand of the prototype design when changing key variables: orientation, area of north and south facing glazing, roof pitch and building form. The results showed marked differences in the thermal performance of the prototype across the seven different climate data regions reflecting the range of climate extremes and their impact on the architectural design. It begins to develop an understanding of the extent to which the different architectural criteria modelled impact on the energy efficiency of the house and the degree to which these can be varied whilst still meeting Passivhaus compliance benchmarks. The study illustrates the need for more nuanced regional solutions to ultra low energy housing in Scotland that better reflects the large regional climatic differences across the country.