Zehnder – Product Showcase

February 2, 2024

Effective ventilation in a well-insulated home

The construction industry’s mission to build homes more energy efficiently and therefore reach targets for net zero in 2050 has meant that homes are now better insulated and airtight, to keep heat in and lower energy costs.

But making a home more airtight doesn’t just stop heat from escaping, it also prevents fresh airflow in and out of the property – meaning that natural ventilation and air leakage is restricted. As a result, dangerous pollutants become trapped inside and without means to extract and change the air, particulate matter and harmful gases (such as CO2 and airborne chemicals) amass, creating a build-up of toxic air within the building.

For a healthy indoor climate, the indoor air needs to be refreshed to extract the pollutants that people bring into the house. Therefore, as we build tighter – and retrofit homes to this new energy efficient standard – an ever greater need to ventilate effectively needs to be employed.

Ventilation can no longer be an afterthought but one that sits boldly at the top of the priority list to provide comfortable, healthy living environments.

How to ventilate right

Mechanical ventilation units with heat recovery (MVHR) are ideal systems to provide optimised, balanced ventilation with heat recovery at 96%. So, unlike simple passive ventilation that allows heat to freely flow out of the building, these systems pass the extracted air over a heat exchange cell which recovers and retains the heat that would otherwise be lost. Not only does this improve the indoor air quality (IAQ), by filtering the incoming air of pollutants, it helps to keep the home warm – thus reducing the energy input it takes to heat up.

Beyond the need to improve indoor air quality, another concern relates to overheating. Within the UK Building Regulations, Approved Document Part O provides guidance to building designers on mitigating overheating in residential buildings and reducing these effects. But problems occur when prescriptive and passive ventilation means can’t be met and the building cannot be modelled under the guide of TM59, which encourages architectural design to minimise the risk of overheating.

Traditional methods of combating overheating often rely on air conditioning units, but this approach can have negative effects on IAQ. By merely recirculating air, these systems can reintroduce potentially harmful particulates such as dust and allergens, compromising occupants’ health and comfort and also cost a significant amount to run.

In contrast, mechanical ventilation with heat recovery units with added air temperation devices, such as Zehnder ComfoAir Q with ComfoClime provide a solution to meet Part O/TM59. More specifically, the ComfoClime system combines heating, cooling, and ventilation in one. It features an innovative reversible air to air heat pump module that tempers and dehumidifies fresh air before it is distributed to individual rooms, resulting in a comfortable climate during both warm and cold periods.

Combining energy-efficient cooling, superior filtration, and fresh air intake through a single system is an approach that can help create a healthier and more environmentally conscious solution for indoor climate control.

Efforts to insulate properties correctly for optimum energy efficiency is consistently top of the agenda, but with every decision to insulate tight, the priority to ventilate right must also top the list. The impact on IAQ and subsequently the health and wellbeing of the occupants inside is essential to the two working together in perfect harmony.

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