Passivhaus

Due to the minimal energy requirement, the Passivhaus standard has been widely recognised and adopted to deliver low carbon buildings. To achieve this standard, the thermal and physical properties of the building envelope have to meet a stringent criteria. It has set out the highest requirement for the building airtightness, which requires the envelope to achieve an air change rate less than 0.6 h-1 when the building is subject to a pressure difference of 50 Pa. Building an envelope with such a high level of airtightness can be extremely challenging.

This paper describes the findings and recommendations of a meta-study examining the actual in-use performance of whole-house mechanical ventilation heat recovery systems (MVHR) installed in 54 low energy dwellings in the UK, as part of a national research programme. The performance of the systems is assessed using monitored data on indoor air quality (temperature, relative humidity, CO2) and energy use, cross-related with actual experiences of operating these systems through resident surveys.

According to the International Energy Agency, buildings represent over one-third of total final energy consumption. Thus, a more sustainable future begins with low energy buildings which must combine comfort and function using passive systems and new evolving technologies. Policies to reduce building energy consumption and carbon emissions have been developed worldwide during the last decades.