Assessment of MVHR systems and air quality in zero carbon homes

MVHR (mechanical ventilation with heat recovery) systems provide ventilation while recovering heat from exhaust air.

It has been widely adopted as an energy efficient design option and in 2013 it was estimated that a quarter of new homes were fitted with MVHR. In practice, however, deficiencies in the design, installation, commissioning and/or operation of MVHR have raised doubts over performance and whether adequate indoor air quality is always achieved. This report presents the findings from a programme of monitoring work on 10 new homes equipped with MVHR at the SSE development at Greenwatt Way in Slough. The work highlights a number of key considerations in the delivery of effective MVHR systems and in particular the importance of developing a detailed design for the system and the need for expert installation and commissioning. Importantly the work gauges the use of these systems by occupants and their feedback on the air quality achieved.