Problems with MVHR systems which are now commonplace in many eco-homes, have caused the NHBC to introduce a new set of standards for their proper installation
New research from the NHBC Foundation based on ten new homes built to Code for Sustainable Homes Level 6 in Slough found that there had been problems with all the installations. Nine of the units were re-commissioned and one was replaced after approximately one year of occupation.
Evidence has shown that if installed incorrectly the performance of MVHR units can be greatly reduced and has been linked to poor indoor air quality.
Attempts to improve airtightness and improve energy efficiency have resulted in a quarter of new homes now containing an MVHR system.
As a result of these failings the NHBC has announced it is introducing a new standard for MVHR to be included in the 2014 NHBC standards.
Paul Cribbens, standards manager at NHBC, said: ‘MVHR systems can offer significant benefits and increasing numbers of house-builders are using them as a practical and cost 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 ground breaking new standard for MVHR is a significant step forward which will benefit both homeowners and the industry.’