How can increased ventilation rates and improved filtration help deliver better Indoor Air Quality (IAQ) in residential buildings?

nice room with good indoor air quality (IAQ)

It is an accepted view, supported by the World Health Organisation (WHO), that increased ventilation and better filtration rates significantly improve the IAQ of our buildings. Increasing the airflow in an indoor space and removing pollutants and contaminants such as particulate matter and gases through filtration, can provide considerable health and wellbeing benefits to its occupants.

The effects of outdoor air pollution on our health are also well known. Estate agency and residential and commercial property consultancy, Knight Frank, states in ‘The Heating & Cooling Study 2020’ that air pollution was referenced in property searches in London areas, which potentially informed buyers’ choices of where to live.

Opening a window can sometimes do more harm than good due to the pollutants in the external air, which is especially true within densely built environments such as city centres. Here, the concentration of indoor air contaminants increases markedly in areas with high outdoor air pollution as the contaminated air is allowed to enter buildings directly, without any form of processing.

Volatile organic compounds (VOCs), mould, and fungi from high humidity levels in buildings are just some of the internal factors that can also affect IAQ , and require extraction if there are to be IAQ improvements. The effect is likely to be higher in modern buildings with less permeable building envelopes, where humid air is more likely to get trapped.

Ventilation, extraction, and filtration are some of the measures that can help reduce the impact of these various pollutants in our homes.

Which available technologies on the market can help improve the IAQ of residential buildings?

There are a variety of technologies that can, through the extraction of humid and polluted air and supply of filtered air, improve the IAQ of a residential property. Some of these can be integrated with other HVAC systems, or be standalone solutions for specific spaces in an apartment or a house.


In this blog, we will concentrate mainly on mechanical ventilation. Although natural ventilation has a valuable place in many types of development, energy efficient mechanical ventilation is more effective in improving the IAQ in a modern, highly insulated building.


What are the benefits of individual mechanical ventilation for residential development?

Individual mechanical ventilation is a cost-effective way to extract air from wet areas, such as bathrooms, toilets, and kitchens. This helps to prevent condensation and mould growth that can affect other areas of a house.


Intermittent mechanical extract ventilation is one of the most cost-effective ways to extract moisture and pollutants from wet areas. Modern extract fans have been designed to ensure easy installation in walls, ceilings, and windows. Some units, such as Glen Dimplex’s Simply Silent range can be fitted internally without the need for ladders to install external grills. 


De-centralised continuous mechanical extract ventilation (dMEV) is ideal for specification where a larger and constant volume of air movement is required to extract moisture from a wet space. Modern dMEV includes intelligent technology that allows the fan speed to adapt to the humidity as required. Centralised continuous mechanical extract ventilation (cMEV) is a term that covers solutions that act similarly to dMEV but can extract air from multiple wet spaces simultaneously. 

How does system ventilation help improve the IAQ in a modern residential development?

System ventilation is becoming increasingly popular as the U-values of our buildings improve. Highly insulated buildings require well designed systems to remove moisture and stale air and prevent condensation, growth of mould, and chronic damp. Retention of the energy used to heat the space is also a concern that a system-led approach can tackle for further improvements.  


Specification of mechanical ventilation with heat recovery (MVHR) means that rather than only extracting humid, polluted air, the ventilation system can also supply filtered, fresh air into a building. Units such as the NaturalAir 180 use G3 grade filters to remove the pollutants from the air. This helps to balance the need for filtration with the requirement for sufficient airflow to ensure the energy efficiency of the unit is not adversely impacted.  


The ability to retain energy from the extracted air makes MVHR increasingly popular in energy efficient buildings. MVHR is frequently specified with ambient communal networks and with fully electric hot water heat pump systems such as the Edel hot water heat pump combined with direct acting panel heaters. These systems are highly energy efficient and deliver occupant comfort and a healthy indoor environment at a relatively low capital cost. You can read more about hybrid electric systems here.  


To discuss how GDHV can help improve indoor air quality and create a healthier indoor environment for your residential development, contact one of our HVAC specialists.