You may think that by designing a new build property or renovating your existing home up to the most modern standards, condensation and mould would never be a problem – but the truth is that no building is immune unless it is protected against the contributing factors.
Condensation is often an overlooked issue that silently creeps into homes, be it new or old, leaving a trail of potentially severe consequences. While it might seem harmless at first glance, when left unchecked, it can cause problems for both the property’s structural integrity and the health of those living inside.
As we aim to create more energy-efficient, airtight homes to meet Net Zero targets and lower our energy bills, many fail to realise the effect it can have on indoor air quality (IAQ). And when buildings lack effective ventilation, excess moisture and stale air become trapped, causing condensation and mould to occur.
Understanding the Risks of Damp and Condensation
Mould outbreaks are caused by excess moisture build up in a property and a lack of adequate air flow to ventilate effectively which can lead to the formation of condensation on cold surfaces, turning water vapour into liquid. This process is common in homes due to everyday activities like cooking and bathing, which can release significant amounts of moisture into the air. In fact, a typical household can generate up to 24 litres of water vapour daily. Without sufficient ventilation, this moisture accumulates and condenses on the colder surfaces including walls and windows, creating an ideal environment for mould to grow.
Ignoring condensation, or indeed what causes it, can have dangerous outcomes. Not only does it result in visible damage, but it can also cause insulation to perform poorly, lowering a home’s thermal performance. This means an increase in demand for heating, higher energy costs and a greater impact on the environment.
But the biggest concern is the risk of mould and mildew, especially toxic black mould which can pose significant health risks among residents. Prolonged exposure can lead to respiratory issues or allergic reactions which is particularly alarming for those more vulnerable, such as young children and elderly individuals, living in the property.
The Role of Ventilation in Controlling Condensation
While it is important to build to energy-efficient, modern day standards, it is equally important to ventilate right as you insulate tight.
Installing the right ventilation system is essential in helping to remove excess humidity from the air as well as removing pollutants and bringing in clean, fresh air that would otherwise get trapped inside.
This can be achieved through modern extract fans, like the Zehnder Unity CV2.1HT, in wetrooms or cooker hoods in the kitchen, with trickle vents on windows to allow air flow to move through the property.
Running at a constant ‘trickle’ rate for year-round ventilation, the Unity CV2.1HT includes an intelligent humidity sensor designed to adapt to real-time conditions to promote fresh and healthy air circulation. The fan is set to operate automatically and boosts when required, activated by either a room’s humidity level or through its smart timer, reducing unnecessary heat loss and energy wastage.
But for a true, whole house, a mechanical ventilation with heat recovery (MVHR) system provides optimised, balanced ventilation with heat recovery up to 96%. So, unlike simple passive ventilation that allows heat to freely flow out of the building, these systems have been innovated to pass the extracted air over a heat exchange cell which recovers and retains the heat that would otherwise be lost.
Not only does this control humidity levels and improve the indoor air quality, by filtering the incoming air of pollutants, it helps to keep the home warm – thus reducing the energy input it takes to heat up.
These systems also aid cooling in the warmer months. A modulating summer bypass activates when temperatures reach a pre-set level, turning off the heat recovery element, and then through the summer, heat and humidity is extracted from the warm, humid outdoor air before fresh air enters the building. The result is a more comfortable indoor climate with a fresh air feel all year round.
For self-builders, choosing the right MVHR system is a long-term investment in health and sustainability. The right ventilation system should be tailored to the specific requirements of the home, particularly if the property has unique design features like converted rooms or a layout with challenging ventilation requirements. In such cases, consulting with ventilation experts to assess requirements and make adjustments is crucial – it should never just be a case of hitting the standard Building Regulations set out in Part F for ventilation and Part O for overheating.
An Investment in Health and Structural Integrity
Regular maintenance of ventilation systems, such as changing filters and cleaning fans, is essential in keeping a home healthy and ensures that they can continue to function as intended whilst the right level of humidity is maintained.
It is important we don’t see condensation and mould as an inevitable problem in our properties. By specifying and installing the right ventilation system at the start of a build, this issue can be effectively mitigated ensuring the structural integrity and health of occupants are protected.
In the end, tackling condensation requires a comprehensive approach. At Zehnder Group UK, we are committed to enhancing IAQ through innovative ventilation solutions that help prevent the issues associated with damp and mould. Ultimately, ignoring the risks is not an option and is a challenge that demands immediate action. Investing in effective ventilation isn’t just about preventing damage, it’s about building a healthier future for all.
By Jason Bennett, indoor climate specialist at Zehnder Group UK