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DOMESTIC VENTILATION: EXTRACT FANS
T
he way we live our lives has changed. Over the past few years, the functionality of our homes has evolved and adapted dramatically and
where a house used to be somewhere to simply live, they have now taken on the role of office, gym and even entertainment centre. The rise of convenience culture has also firmly established itself into modern culture, meaning that often we don’t need to leave the house for anything. As a result, statistics show that we now spend
over 90 percent of our time indoors, but this modern way of living presents challenges when the workings of our homes aren’t set up right for these increased pressures on its systems. Humidity is one of these challenges. Cooking, bathing, working out and having more people in the house all day lead to increased levels of water vapour being released into the air. In fact, the average family can easily create 24 pints of it a day, but once produced, where does it go? In previous times, our leaky houses would cope better with this challenge as natural ventilation points in the building’s fabric would exist to allow air flow around the property. Our modern homes however are being more tightly insulated for energy efficiency and as a result, trapping this moisture inside with no room to escape. The excess humidity build-up in a property,
combined with a lack of adequate air flow to ventilate that moisture effectively, causes condensation to form on cold surfaces, turning water vapour into liquid. Without means to remove it, droplets become too heavy to stay in the air and settle on cold spots - often windows or sills. These damp conditions provide the perfect environment for mould and mildew to develop, which can have a serious impact on the building’s structural integrity and indoor air quality that affects the health of those inside. Persistent condensation on walls and ceilings in
colder weather can damage interior finishes and the prolonged moisture accumulation can then lead to the decay of building materials. Over time, this deterioration can weaken structural components, resulting in costly repairs and jeopardising the safety of the house. Condensation-induced moisture also undermines the effectiveness of insulation materials, reducing their thermal performance and in turn defeating the point of insulating for thermal efficiency. This constant battle between warm indoor air and cold external surfaces leads to increased energy demands for heating, driving
Creating healthier homes: the importance of
Above: Stuart Smith, indoor air quality specialist at Zehnder Group UK
ventilation in modern living
Stuart Smith, indoor air quality specialist at Zehnder Group UK discusses why ventilation is so critically in tightly insulated modern homes
up energy costs and putting strain on building systems.
But most alarmingly, the conditions allow for
toxic black mould to take over, which poses a serious health risk to humans, especially those with low immune systems or the vulnerable like children or the elderly. The spores released into the air can lead to a variety of respiratory problems and allergic reactions among occupants.
Mitigating the Issues
Managing condensation in homes requires a multi-faceted approach and the right balance of heating and ventilation. Upgraded insulation must be considered in partnership with an effective ventilation system to help regulate indoor humidity levels and promote a healthy indoor environment, minimising the conditions conducive to condensation. There are two main ways to achieve this. The first is a simple yet continuous air system
comprising of trickle vents on windows and dMEV extract fans with humidity boost in wet rooms throughout the home. Trickle vents are designed to work harmoniously with extractor fans, forming an effective whole-home ventilation system. By allowing a continuous flow of fresh air into a property, these vents work in tandem with
the extractor fans, which efficiently remove the stale, moisture-laden air. New fans on the market, like the Zehnder Unity CV2.1HT, run constantly with an integrated humidity sensor to give a boost, or more demand ventilation when it is needed, such as after showering or while drying clothes. They are whisper quiet and run at a minimal cost - less than £2 per year. This intelligent air flow system not only enhances indoor air quality but also helps prevent condensation and mould, ensuring a healthier living environment for occupants. The second option to protect homes against this build-up of poor indoor air quality is a mechanical ventilation system with heat recovery (MVHR). With an MVHR ventilation system stale air is extracted but before leaving the house, the air passes over a heat exchange which recovers the heat that would otherwise be lost outside. A warm, filtered fresh air supply is then fed back into the property. MVHR systems provide ventilation with heat recovery of up to 96%, which can reduce the load on heating systems. Then in the summer months when cooler air
is required, the MVHR activates its modulating bypass to prioritise the recovery of the cooler air through the system. This provides a comfortable climate all year round as well as clean, fresh, filtered air for better occupant health and wellbeing. The way we live will constantly evolve and change but the speed in which we upgrade and renovate our existing homes as well as build new ones doesn’t always keep pace. Therefore, it is essential that we futureproof our homes to protect our health and wellbeing for years to come with the right systems, working together, in place. This balanced and strategic approach will prevent problems arising and keep up with our ever-changing lifestyles.
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