Ventilation & heat recovery


www.heatingandventilating.net


The evolving role of ventilation


Paul Williams, Domus Ventilation product manager, discusses the changing role of ventilation in in keeping indoor environments safe


I


t’s safe to say that good ventilation never used to be high on the list of priorities in the housing sector and was usually restricted to windows, extract fans and air bricks. The focus was very much on condensation and mould


prevention. How things change! We still have condensation and mould to contend with, but now the list has


expanded to dealing with overheating in the more air tight new homes we build, addressing the issue of air polluted by excess PM2.5 and NOx, and reducing air born virus transmission. Ultimately, it all comes down to improving indoor air quality (IAQ) in our


homes. Whilst the Government works on wider issues to tackle outdoor air pollutants, there are a number of things we can do to reduce potentially harmful pollutants indoors, including using non-toxic cleaning products and moving away from fossil fuels in properties. The third key aspect is to disperse pollutants in residential properties through effective ventilation. Whilst extract fans in bathrooms and kitchens provide a basic level of


ventilation and are low in cost, a far more effective solution is whole house mechanical ventilation solutions. Mechanical ventilation with heat recovery (MVHR) is top of this list as these


systems combine supply and extract ventilation in one system. As I’m sure you’re aware, they work on the principle of extracting and re-using waste heat from ‘wet rooms’ (kitchens, bathrooms, utility spaces). They efficiently pre- warm the fresh air drawn into the building with waste stale air using a heat exchanger. The filtered, pre-warmed air is then distributed around the home, effectively meeting part of the heating load in energy efficient dwellings. For example, Domus Ventilation’s new HRXE-HERA and HRXE-AURA MVHR units feature advanced heat exchange proficiency enabling up to 95% of waste heat to be recovered. They come with 100% thermal (summer) bypass which automatically activates when the air temperature reaches a pre-set level, allowing in cooler, fresh, filtered air without warming it through the heat exchanger. MVHR systems provide effective ventilation, are energy efficient and


extremely effective at reducing the risk of virus transmission, condensation and cold air draughts. A lower cost, easier to install alternative to MVHR, mechanical extract


ventilation (MEV) systems are also available. These actively extract air from wet rooms via ducting to a central ventilation unit which exhausts to the atmosphere. The systems are typically two speed, providing low speed continuous trickle


ventilation and high-speed boost flow. Replacement fresh air is drawn into the property via background ventilators located in the habitable rooms and through air leakage.


Whilst whole house mechanical ventilation systems are effective in distributing fresh air throughout the home and dispersing pollutants, if that incoming air is polluted in the first place – especially if the property is located near a busy road – then it’s important to add filtration to the system. For example, Domus Ventilation’s NOX-FILT, works on the supply leg of the ducting system of a mechanical ventilation system and prevents up to 99.5% of NO² pollution from entering a home. There are two units in the range with the second one having the added benefit of a PM2.5 pre-filter. The WHO estimates that every year, exposure to air pollution causes seven


million premature deaths worldwide and results in the loss of millions more healthy years of life. In the UK alone, Public Health England estimate 28,000 - 36,000 deaths a year in the UK can be attributed to long-term exposure to air pollution, making it the biggest environmental threat to health in our country. Experts agree that both source removal and ventilation are key to reducing indoor air pollutants. Reducing PM2.5 and NOx to within safe limits are the long term goal but, in the meantime, we have to rely on ventilation and filtration to make our indoor environment safe and comfortable. Mechanical ventilation is being recognised as a valuable and relatively low cost means of achieving this, which also addresses the ongoing issues of managing humidity levels in our homes for a comfortable and healthy environment.


30 February 2022


DOWNLOAD THE HVR APP NOW


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36