How Overheating Can Compromise Indoor Air Quality

How Overheating Can Compromise Indoor Air Quality

By Ruth MacEachern

Product Manager

With elevated oil and gas prices among the key contributors to the recent cost of living crisis, there are valid financial reasons as to why Developers and M&E Consulting Engineers should seek to avoid overheating in the design of their homes, not to mention the effect that the needless consumption of heating fuels has on the environment. However, in this article we will consider the effect that overheating a building can have on indoor air quality (IAQ), with a focus on the consequences that poor air quality can have on the health and comfort of a building’s residents.

What causes overheating in a building?

Environmental protection is an increasingly important topic with regard to the design and renovation of the UK’s housing stock, a fact that has been seen reflected in amendments to the building regulations. 

Under the banner of the Future Homes and Building Standard, the government has set ambitious targets to improve the energy efficiency of housing, whereby new houses built after 2025 should produce 75-80% less carbon emissions, and thus achieve net zero carbon emissions by 2050. 

One of the ways this can be achieved is by increasing the airtightness of buildings, however, this brings with it a host of ventilation requirements if we are to avoid overheating and poor indoor air quality. This fact can be seen reflected in the recent amendments to Approved Document F, which stipulates increased requirements for whole dwelling, and mechanical ventilation rates. For natural ventilation with intermittent extract fans, this is not considered suitable for airtight dwellings and an alternative ventilation method should be chosen, with Mechanical Ventilation with Heat Recovery (MVHR) being the preferred choice. . While an airtight building will satisfy requirements regarding emissions and will certainly not leave residents suffering from the cold, a poorly ventilated airtight home risks becoming overheated, with stale air posing an array of health risks. A study conducted by the Birmingham City School of Engineering and the Built Environment corroborates this premise: “Poor indoor air quality and overheating can affect housing residents' health and comfort, yet a number of factors including building regulations contribute to the proliferation of these issues in new housing”.

More information on the Future Homes Standard and a detailed overview of the relevant regulatory changes can be found here.

What are the health implications of poor IAQ?

The health implications of poor indoor air quality are far-reaching and varied. The World Health Organization estimates that household air pollution was responsible for “3.2 million deaths per year in 2020, including over 237,000 deaths of children under the age of 5”. The same report elaborates that “household air pollution exposure leads to noncommunicable diseases including stroke, ischaemic heart disease, chronic obstructive pulmonary disease (COPD) and lung cancer”. 

While these perhaps extreme cases are often the result of indoor cooking using combustible fuels, especially in developing countries, the risks that poor IAQ poses to residents in developed countries is by no means negligible. A report by the United States Environmental Protection Agency lists among the health effects associated with indoor air pollutants:

• Irritation of the eyes, nose, and throat.
• Headaches, dizziness, and fatigue.
• Respiratory diseases, heart disease, and cancer.

How does overheating affect indoor air quality standards?

A study conducted by Taylor J, Mavrogianni A, Davies M, et al., investigating the correlation between overheating and the levels of a particular indoor air pollutant, PM, found that “indoor temperature and air quality in dwellings are closely coupled”. The study identifies that differences between indoor and outdoor temperatures can influence airflow, with changes in ventilation resulting in a build-up of pathogens. Other research, for example, a study into the effects of temperature on the air quality in classrooms have discussed increased CO2 levels as a result of elevated temperature combined with poor ventilation. Elevated levels of other contaminants and pollutants, such as dust mites, mould, radon, carbon monoxide, as well as increased humidity can all be results of excessively high temperatures in interior living spaces. 

There are a number of factors that contribute to overheating, such as airtight energy-efficient building design and retrofitting projects, the orientation of the building in relation to the sun, positioning of properties in relation to other dwellings in the case of multi-storey apartment buildings. What is clear is that considerable expertise is required when designing buildings, performing refurbishment work, and installing adequate ventilation. Our articles on ventilating the homes of the future and providing tips on ventilation design propose a number of ways to mitigate overheating and improve air quality, including:

• The installation of a MVHR systems
• The adequate use of trickle vents
• The appropriate design and planning of ducting routes

Preventing overheating: solutions and expertise to improve indoor air quality

The discussed health issues more than justify investment in a high-quality ventilation system to improve indoor air quality standards– not to mention the increased comfort that a well ventilated and suitably warm/cool interior climate can offer residents of a dwelling. 

EnviroVent can help plan a tailored installation, taking into account the layout of the property, external and internal conditions, and airtightness. Contact our experts regarding the installation of an MVHR ventilation system and protect the health of those who purchase your homes, set your homes apart from those built by other developers thanks to improved energy efficiency and cheaper running costs, and do your part to protect the environment.