NHBC survey shows poor results of MVHR systems in homes
Following poor results for a survey of mechanical heat recovery system in homes (MVHR), NHBC (National House Building Council) is revising its guidance for including in the 2014 edition of ‘NHBC standards’. The research monitors 10 homes in Slough built to Level 6 of the Code for Sustainable Homes over 18 months. The report found that nine of the units were recommissioned and that one was replaced after about a year of occupation. Previous research by the NHBC Foundation and Zero Carbon Hub has also revealed a number of issues with MVHR systems.
Analysis by NHBC, the UK’s leading warranty provider, has found that the move to create homes that are more energy efficient and to improve airtightness has led to about a quarter of new homes being fitted with MVHR systems.
The new technical guidance will cover issues such as design, ductwork, location of the fan unit and preventing condensation.
Paul Cribbens, standards manager at NHBC, says, ‘MVHR systems can offer significant benefits, and increasing numbers of house builders are using them as a practical and effective way of meeting ventilation and energy-efficiency requirements.
‘But these systems must be correctly designed and installed, or design performance can be greatly reduced. NHBC’s new standard for MVHR is a significant step forward which will benefit homeowners and the industry.’
