How MVHR is on the frontline of damp prevention

min read time
2023-05-19 14:24:33

In this article we take at look at how mechanical ventilation with heat recovery (MVHR) can help to prevent damp whilst balancing building regulations for ventilation with enery efficiency.  

Prioritising damp prevention in new developments seems a little counterintuitive today – surely damp and mould are problems for older housing stock? While this is generally true, damp has become a focal issue and forward-thinking UK developers are paying close attention to broad changes taking place that will increasingly affect the new-build market, too.

The first thing to note is that preventing damp is much more front-of-mind for house buyers than it used to be. Headlines about the impact of prolonged exposure to mould have educated the public about the serious health consequences of damp housing, particularly for children. This awareness is significant because it’s happening just as the cost-of-living crisis is pushing huge numbers of people to turn their heating down, or even off completely - and colder houses make the prospect of damp more likely. Growing awareness of the issue, and the increased likelihood of damp and mould creeping in, makes damp prevention an important issue for a lot of people – including buyers of new houses.

Smart developers are adapting their plans so that they’ll be ready to address buyers’ concerns about damp protection in a cooler home. With one eye on the possibility that building regulations could be tightened to tackle this issue, they’re future-proofing their developments by fitting market-leading Mechanical Ventilation with Heat Recovery (MVHR) technology to both supply and extract air throughout the house.

There’s a strong argument for moving to MVHR in your developments now, that’s why, in this article, we put the facts at your fingertips.


The issue of dampness in housing isn’t going anywhere

Current UK government statistics only reveal the tip of the damp issue; as citizens continue to keep their heating off to cut costs, it’s likely that the problem will increase exponentially. Looking at the scope of this, we know that, across Europe, an estimated 36 million people were unable to keep their homes adequately warm in 2020. And, according to the government’s English Housing Survey, around 904,000 homes in England had damp problems in 2021. As the cost-of-living crisis builds, it’s likely increasing numbers of residents will struggle to manage damp incursions caused by cooler house temperatures and these numbers will rocket.

Damp and mould are significant threats to health

As the number of homes suffering from mould increases, so will the health consequences. The evidence has been clear for some time: the NHS reports that people with damp and mould in their homes are more likely to suffer from respiratory illnesses, infections, allergies or asthma. The cost of this further reveals the scale of the issue: each year, the NHS spends an estimated £1.4 billion on treating illnesses associated with living in cold or damp housing.

Mould causes problems because breathing in or touching the spores it releases can trigger an allergic reaction and, by irritating the lungs, can exacerbate conditions such as asthma. The relationship between damp, mould, and asthma is particularly strong. The World Health Organisation found that damp housing contributes to up to 15% of new cases of childhood asthma in Europe and that, for those children, lung function worsens with every degree the temperature drops in their home.close up of ironing tool  on white background

Is our love of ‘airtight’ homes part of the problem?

It’s important that developers are aware of how modern living can increase the likelihood of dampness and mould so they can take action against it. Newer housing stock is well insulated to increase energy efficiency, but this reduces the natural airflow and ventilation via draughts that older houses experience. Today, it’s easy for someone living in a newer house to seal moisture into their home without realising it. After all, particularly as energy bills rise, it appears to make sense to close all windows and window vents to keep as much valuable heat in as possible.

However, this lack of ventilation creates the ideal environment for mould. Water vapour from cooking, cleaning, breathing and drying clothes indoors has nowhere to go in a sealed house. And a cooler indoor air temperature (more likely as people turn their heating off) increases the likelihood that the water vapour will condense on cold surfaces, resulting in mould spots.

Will updates to ventilation regulations make a difference?

From 15 June 2022 in England and 23 November 2022 in Wales, updates to Approved Document F of the Building Regulations covering background ventilation come into effect. These are designed to make sure adequate ventilation is provided to prevent excess condensation from building up. All newly fitted doors and windows must have a trickle vent that creates a small hole to provide permanent ventilation when the door or window is closed.

However, professionals within the window and door industry worry that these changes will cause more problems than they solve and that homeowners will simply block them up. Experts point out that trickle vents can let in noise and insects, pollution, and drafts in high winds. There’s also the potential for vents to let, cold air into the property – adding to localised condensation and mould risk. Plus, experts highlight that cost-conscious homeowners aren’t going to want to let expensively warmed air escape.

MVHR gives developers an edge on the critical issues of damp and mould

MVHR systems are ideally placed to tackle ventilation in ‘airtight’ homes facing lower heating temperatures. They’re a highly efficient way to preserve heat in the home while at the same time keeping a through-flow of air that ventilates the property, removing the risk of condensation, dampness and mould.

Fundamentally, an MVHR system moves warmth from rooms that produce the most heat to cooler rooms, filtering out any fumes and external environmental air pollutants. Tucked away in a loft or cupboard, the ventilation system is discreet and quiet and provides a whole-house solution. Plus, in the summer months, the heat recovery element of MVHR systems can be bypassed without affecting its ventilation abilities, keeping the house cool. Looking specifically at MVHR’s mould-busting properties, its continual circulation of fresh, warmed air extracts moisture-laden air, depositing the condensate into a drain cutting condensation and dampness.

For developers looking to address the growing problem of dampness and mould in a whole range of properties, MVHR has huge potential. Read our article about the benefits of MVHR systems.

Indoor Climate Solutions at Wavin

At Wavin, our purpose is to build healthy sustainable environments. Our tailored indoor climate solutions feature our market leading systems and products including underfloor heating, heat interface units, MVHR and single controls (interfacing with all of these technologies). They provide the following benefits:

  • Improved energy efficiency
  • Low maintenance
  • More space and design freedom
  • Compatible with all floor types and coverings
  • Comfortable environments with even heat and less dust
  • Full zone control
  • Flexible solutions including installation and after-sales support
  • Design and system selection support
  • Wavin’s extensive experience in residential projects as the market leader in Europe