INDOOR AIR QUALITY


Thermal imagery of a typical HVAC system


conductivity and proven compressive strength, it is possible to prevent cold spots, safeguard insulation performance and protect against the moisture risks associated with condensation. This approach requires careful


Boost IAQ without compromising building performance


Paul Beech explores how HVAC systems can both improve and compromise indoor air quality, and why tackling thermal bridging is key to healthier, more efficient buildings.


Paul Beech www.armatherm.co.uk


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General manager of Armatherm


ccording to the National Human Activity Pattern Survey (NHAPS), adults in the UK spend approximately 90%


of their lifetime indoors, often exposed to harmful chemicals because of mould spores, household products and a lack of ventilation. Because of this it has become vital to improve indoor air quality due to the health risks associated with poor IAQ. This has seen a rise in the implementation of more HVAC systems which include innovative air filtration systems. HVAC systems have become an


essential component to improving air quality, however they can use excessive energy to keep a building at a constant temperature due to being susceptible to thermal bridging. Because the HVAC system penetrates the building envelope, it could be a prime cause of creating a thermal bridge. So, despite improving IAQ, they’re not particularly efficient or cost-effective.


Defi ning indoor air quality Indoor air quality is something we’re hearing more and more - but how


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important is it and what can we do to improve it? The literal definition of indoor air quality might seem obvious, but there’s much more to it than meets the eye. Not only does it refer to pollutants in the air, it also includes temperature, humidity, CO2 levels and microbes, elements you may not have even considered could be impacting your health and wellbeing daily. With indoor workplaces, schools and homes forming the backdrop to most of our lives, air quality management essential, but it also means that the way we control temperature and ventilation within those spaces plays an equally important role. Over the last decade there has been a growing emphasis on mechanical systems as the fastest way to guarantee improved air quality, yet the way those systems are integrated into the building envelope is often overlooked. The irony is that solutions designed


to protect health and comfort can, if poorly specified, create new risks. HVAC units, vents and associated ducting must penetrate walls, roofs or façades, breaking the continuity of insulation. This creates a pathway for energy to escape and cold spots to form. Known as thermal bridges, these


areas of weakness can cause more than just higher heating bills. By lowering surface temperatures in localised areas, they increase the


risk of condensation forming. Over time, this moisture provides the perfect conditions for mould growth, undermining the very indoor air quality the HVAC was installed to protect. The presence of mould spores and damp conditions has been linked to both respiratory problems and allergies with the subsequent long- term health issues these can lead to, particularly in vulnerable occupants. Energy loss through thermal bridging also means that HVAC systems need to work harder to maintain a consistent indoor climate, increasing operating costs and contributing to higher carbon emissions. In effect, the building becomes caught in a cycle of trying to solve one problem while exacerbating another.


Thermal solutions The answer lies not in reducing the uptake of HVAC systems, which clearly play a role in ensuring cleaner indoor air with smart filter systems, but in addressing how they are integrated into the building fabric. If penetrations through walls and roofs are unavoidable, they must be thermally isolated in a way that prevents direct heat transfer. Thermally isolating fixtures such


as brackets, supports and equipment mounts ensures that the continuity of insulation is preserved. By using materials engineered with low thermal


specification. Not all thermal break materials perform equally, and it is critical to assess claims around conductivity, load-bearing capacity and durability in real-world conditions. Independent testing, certifications and a track record of successful installations should be the benchmarks by which products are selected. For designers and engineers, understanding how a small detail like how a support bracket interacts with the wider building envelope is key to preventing performance gaps. By placing greater emphasis on the building physics behind HVAC integration, we can strike the balance between healthier indoor environments and truly efficient, sustainable performance. In practice, this means treating HVAC penetrations as critical junctions rather than secondary details. Just as a weak link compromises the strength or the chain, even minor discontinuities in insulation can undermine the whole thermal strategy of a building. As energy efficiency standards tighten and pressure mounts to reduce operational carbon, these details cannot be ignored.


Future focused The drive to improve indoor air quality is both necessary and urgent, but it should not come at the expense of the long-term integrity of the building envelope. Thermal isolation of fixtures is a straightforward but powerful measure that aligns health, comfort, energy efficiency and sustainability goals. For specifiers, it represents an opportunity to ensure that investments in advanced mechanical systems deliver their intended benefits without creating unintended consequences. As industry specialists here at Armatherm, we have long emphasised the importance of getting these details right by educating and supplying the industry with all things thermal breaks. By providing proven thermal break solutions designed to isolate structural connections and mechanical penetrations, we support designers in minimising heat loss and reducing the risk of condensation. As the conversation around indoor


air quality continues to grow, it is essential that thermal bridging is seen as part of the same dialogue. Only by addressing both together can we create buildings that are healthier, more efficient and fit for the future. ■


EIBI | OCTOBER 2025


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