NEW study shows MVHR is the best ventilation strategy for every home

NEW study shows MVHR is the best ventilation strategy for every home

The Passivhause Trust, alongside others, have recently broadcast a new study showing that MVHR is not just beneficial in airtight properties. This study goes against the trend of reports portraying MVHR as an inapropriate ventilation strategy where air tightness is >3 m³/m2.hr and is a waypoint for all new builds, not just those reaching high levels of airtightness.

This report could not have been delivered during a more vital time. As the country fights the battle against Covid-19 we should be looking for better air quality within the homes we spend 90% of our time in (even when not in lockdown) and this study shows exactly how we can do that.

By having an MVHR system specified, designed, installed, commissioned, and maintained to best practice (Passivhaus) standards it will provide you with the fresh quality of air required to live a healthy lifestyle. By filtering out pollutants (NOx/SOx), nasty particulates and pollen before it enters the home and extracting potentially damaging stale/humid air, VOC’s from cleaning products and furniture, as well as dust particulates, MVHR can create a balanced and healthy indoor climate for any home.

How does this study change constuction industries approach to ventilation?

Previous studies, such as those by Lowe and Banfill et al, concluded that MVHR should only be used in buildings which have low air permeability; as the energy required from the MVHR to ventilate the property and maintain the temperature would be more than it’s worth compared to other ventilation strategies. Penalties were added to the MVHR for using more energy from requiring increased ventilation rates as well as increased heating demand to maintain the heat exchangers efficiency. However, what this new study from the Passivhaus trust shows is just how flawed this approach is.

What they prove is that the MVHR will keep a constant ventilation rate no matter the air infiltration of the rest of the building, so this will have no bearing on the energy used. It also provides data to show that the MVHR will use the same amount of energy even with a lower internal temperature due to higher air infiltration. This is because the MVHR’s heat recovery will be more affected if the whole house heating system is inefficient, rather than the MVHR’s heat exchanger.

Where previous reports added ‘penalties’ to the MVHR system but not to other ventilation strategies, this new study does not, and in fact shows how much better an MVHR would be at each level of air permeability.

So rather than using flawed ventilation methods which; do not achieve the right amount of air changes for a healthy home; do not filter out incoming and outgoing air; do not provide fresh air to every part of your home; do not extract stale humid air; do not work without human intervention; and do not effectively recover up to 96% of heat within your home. Use a ventilation strategy that works.

MVHR has been proven to work on all these fronts and now, due to this report, has been extended to work in every building whether new or old, airtight or not.

To find out more please get in touch and we will be more than happy help.

Passivhaus Trust – The Case for MVHR