Marin Passivhaus is a project in construction in the small village of Brankovtsi, about 40 min from Sofia in Bulgaria. Aiming for a Passivhaus certification, it is a self-build, two storey, single-family home with 169 m² (1815 sqft) of Treated Floor Area.
Fabric is timber frame construction with mineral wool insulation and a smart membrane air tightness layer. Wall U-value is 0.104 W/(m²K) (R-54 hr.ft2.°F/BTU in IP units), roof U-value is 0.067 W/(m²K) (R-85 hr.ft2.°F/BTU) and floor is over an unheated basement with U-value 0.154 W/(m²K) (R-37 hr.ft2.°F/BTU).
Systems are still being installed, but it will have an ERV and a heat pump for heating/cooling and hot water.
Greatest challenge were thermal bridge calculations on the perimiter due to an unheated basement. It required extra calculations according to Passive House Insitute instructions.