The Importance of Filtration Systems in Residential Indoor Air Quality

The Importance of Filtration Systems for Residential Indoor Air Quality

By Ruth MacEachern

Product Manager

Having addressed the importance of ventilation systems in maintaining indoor air quality in domestic dwellings, this article will consider the role and benefits of air filtration. In so doing we will provide a summary of the different types of air filter, while also offering maintenance tips to ensure that installed ventilation systems continue to operate at peak performance.

The role and benefits of filtration systems in managing and improving IAQ

One of the key roles of a domestic ventilation system is to improve indoor air quality, creating a more comfortable and a healthier indoor living environment. Stale air, potentially containing allergens, pathogens and volatile organic compounds (VOCs) are extracted out of the property and replaced with a flow of fresh air from outside.

The recent coronavirus pandemic acutely highlighted the need to ventilate confined interior spaces in order to reduce the spread of viruses and bacteria. However, with no guarantee that the air drawn in from outside the building will be free from the same pollutants that we seek to remove, it is clear that air filtration has a major role to play. The effectiveness of air filtration in eradicating harmful pathogens from the breathable air inside a building was recently demonstrated in a study conducted by a team at the University of Cambridge, wherein it was demonstrated that the use of HEPA air filters removed almost all traces of airborne SARS-CoV-2.

A publication by the Federation of European Heating, Ventilation and Air Conditioning Associations argues that the requirement for air purity has increased by virtue of the heightened awareness of indoor air quality. Irrespective of levels of awareness, the tightening of legislation in relation to domestic indoor air quality has been at the forefront of the minds of house builders and home buyers alike. But how exactly do air filters work and what are the different options available?

Air filters: the operating principle explained

An article in Constructing-Specifying Engineer, an online specialist journal for the engineering and construction industry, clearly and concisely explains how filter mechanisms work: “In general, media air filters function by forcing air to flow through a fibrous media. As the air flows through this media, some of the particles in the air are captured by the media”. The article goes on to explain five main mechanisms by which particles are captured, namely straining, inertial impingement, interception, diffusion and electrostatic effect. The article in question is available here should you be interested in reading up on the various mechanisms in greater detail.

There are many materials that can  be used for the filter , with the most common being fibreglass and plastics such as polypropylene and expanded polytetrafluoroethylene (i.e. Teflon). These are then arranged as a flat panel, in a pleated configuration, or as a series of pockets (known as a bag filter). Arguably the most common type of filter is the HEPA (High-Efficiency Particulate Air) filter. HEPA filters are made from a dense layer of pleated material and are designed to trap even smaller particles, such as mould spores, bacteria, and pollen.

It is important that you choose a filter that is compatible with your ventilation system, the size of the building, and the type of pollutants present. A clean and effective filter will improve the efficiency of your ventilation installation and extend its service life, eradicate odours, and eliminate airborne pathogens and allergens.

Ventilation filter maintenance tips

If the occupants of your homes are to reap the aforementioned benefits of a filter-based ventilation system, it is important that the correct filters are used and that the respective units are properly maintained. Better Homes & Gardens provides a 4-step guide on how to clean HVAC air filters…

1. Turn off the power and locate the filter
2. Vacuum the air filter
3. Wash the filter with vinegar and water
4. Let dry and replace

It of course goes without saying that the manufacturer’s instructions for your specific filter will supersede any advice provided by other sources. A guide to selecting the right replacement filter to fit the various EnviroVent ventilation units can be found here. For further reading, you may wish to check out our articles on the running costs of mechanical ventilation systems.