Passivhaus homes are known for their high quality, low energy approach. The results consistently receive positive customer feedback. Certification requires the assessment of the As-Built home, ensuring that design intentions are realised, something that is commonly highlighted as a major issue with standard Part L compliance.
Homeowners report liking Passivhaus buildings due to the low energy bills and because their homes are draught free with no cold surfaces, whilst also resilient to overheating during the hotter months. Ventilation systems are efficiently designed, almost silent and deliver a consistent supply of fresh air resulting in superior indoor air quality. These characteristics are achieved through a holistic design approach, requiring consideration throughout the project.
Although Part L related targets are the main energy efficiency concerns for the majority of developers, the Passivhaus design process can assist with meeting Building Regulations targets, typically through minor changes in design. By evaluating building design through the Passivhaus method it is also possible to achieve a level of quality which SAP alone would not.
The key features to the Passivhaus approach are:
- Designing Out Thermal Bridging – Considering the continuity of the insulation layer early on in design can result in minimal heat losses at construction details. Passivhaus requires the full evaluation of all cold bridges and has strict standards for their impact on surface temperatures and dwelling heat losses.
- Reduced Heat Loads means Reduced Heating Infrastructure – Decreasing the demand for heat in a home can reduce the scale of heating equipment. Passivhaus homes are designed to be heated through low-level electric duct heaters only.
- Efficient Ventilation Design – Following simple rules for duct runs and mechanical ventilation layout early on in design results in a system with reduced power consumption and fan duties. The final system will be smaller and quieter, whilst still providing higher than minimum levels of fresh air.
- Achieving Airtight Buildings – An important aspect of meeting toughening fabric standards in Building Regulations. Passivhaus homes are built to very strict air leakage standards. Considering how the airtight layer transitions around the home throughout the design process, is key to achieving good results.