Mechanical ventilation with heat recovery is sometimes seen as the only option for ventilating a new build eco home - but is it?
When researching ventilation options for new build homes, MVHR can appear as if it is the only option. What is often missing from this conclusion are the properties of the building that need to be in place for MVHR to be the best solution.
One key limitation to MVHR is that it can only extract heat energy from air that passes through it. Any air that passes through the building fabric instead of the ventilation system takes its heat energy with it.
Routing enough of the airflow through the ventilation ducts for MVHR to deliver energy savings requires building fabric that is twice as airtight as the UK building regulations propose, and that proposal is intended to mandate what they regard as highly energy-efficient buildings.
Meeting such a high standard of airtightness comes with a high price tag, both for the building fabric itself and for the extensive ductwork needed to meet all of the building's ventilation needs.
There is a more detailed response to this question here in our blog: