BICKNOLLER Passive House Plus case study in Somerset, England

Existing site restrictions ruled out the easiest route to a good Passive House form factor: going up. The brief was to replace an ageing single-storey dwelling with a new one-storey home that still achieved Passive House Plus - turning the hardest typology for heat loss into one of the best-performing, incorporating vaulted ceilings, a carefully sized mezzanine and disciplined glazing control, rather than extra storeys.

The site sits in Bicknoller, a village on the edge of the Quantock Hills in Somerset, where the new house replaces an oil-heated bungalow with noticeable room-to-room temperature swings. The single-storey constraint is answered directly in the design: a vaulted living space is balanced against flatter ceilings and a mezzanine elsewhere on plan, reducing the external envelope relative to floor area and bringing the heat loss form factor down from an early 3.99 to 3.32.

Key figures:

· GIA: 302m² / 3,251 ft²

· TFA: 240m² / 2,583 ft²

· Form factor: 3.32

· Space Heating Demand: 15 kWh/(m²a) - Passive House Plus

· Heating Load: 11 W/m² - Passive House Plus

· Renewables: Air source heat pump for space heating and hot water, plus roof-mounted solar PV with battery storage

Bicknoller Passive House meets the Passive House Plus criteria through a high-performing building envelope, triple-glazed windows, mechanical ventilation with heat recovery (MVHR; 89% efficiency), thermal-bridge-free construction, and a rigorous airtightness strategy.

This home is designed to substantially exceed Part L of the Building Regulations (England): PHPP modelling shows an annual heating energy demand far lower than a Building Regulations-compliant equivalent, backed by on-site solar generation sized to meet the home's own energy use across the year - the standard required for Passive House Plus certification.