Homes are increasingly designed to save energy, but what can we do to prevent side-effects that pose a cost to our health?

As we strive for continual improvements in energy efficiency, our homes are increasingly insulated and sealed. With undeniable benefits for heating bills, CO2 emissions and those living in fuel poverty, we develop new materials to retain heat and fill every visible crack.

Yet throughout this process, the impact on the indoor environment has often been overlooked. As we begin to understand the importance of internal housing conditions to good health and wellbeing, we’re shedding light on how some building designs compound problems with indoor air quality.

Several things influence the state of our indoor environments. Heating, insulation, ventilation and people’s behaviour, along with a property’s type, orientation and geographic location, all work to affect air quality in our homes.

Over recent years we’ve witnessed a rise in allergic diseases that can’t be explained by factors such as genetic changes alone. With one in three people suffering from allergies in industrialised countries, there has been an increasing focus on indoor air quality. A robust body of evidence now suggests that rates of allergic and respiratory disease are linked to poor indoor housing conditions.

Efforts to prevent heat loss by reducing ventilation have led to undesired consequences for indoor air quality – increasing indoor dampness and the risk of fungal contamination

Based at the University of Exeter Medical School’s European Centre for Environment & Human Health, the European Centre for Environment & Human Health has just published findings that show damp and specific types of mould can pose a significant health risk to people with asthma.

We critically reviewed the findings from 17 studies in eight different countries and found that the presence of several types of mould – among them Aspergillus and the antibiotic-producing Penicillium – can lead to breathing problems in asthma sufferers, worsening their symptoms significantly. It also looks as though mould may actually help to trigger the development of asthma, although research in this area is still in its infancy.

With over 10 varieties found in a typical home, most people may not be aware that moulds are absolutely abundant in our outdoor and indoor environments. And if you have a house or flat that suffers from damp, you’re more likely to have more mould.

So what about the causes of damp? The structural integrity and architectural design of a (typically old) building can often let in water. Poor ventilation and heating can then increase indoor humidity, with this moisture ultimately condensing on cold surfaces and promoting the growth of mould.

Greater household energy efficiency can lead to a number of health benefits and help make a property more affordable to heat. However, efforts to prevent heat loss by reducing ventilation have led to undesired consequences for indoor air quality – increasing indoor dampness and the risk of fungal contamination, which is affecting around 16% of European dwellings.

The extent to which a home is heated and ventilated is also largely controlled by the habits of its occupants, and the way people live in their homes varies hugely. For example, some people dry their washing on indoor racks, some shower with the window closed, and many keep their windows and doors closed as much as possible in winter. All of these behaviours can increase the humidity and dampness in a home, with poorer families less likely to maintain adequate ventilation through the winter and commonly failing to heat the whole building.

Even mould just visible outdoors can mean air quality changes indoors.
Even mould just visible outdoors can mean air quality changes indoors.

Crucially, we know little about how these behavioural factors contribute to damp and mould in homes that have been retrofitted to make them more energy efficient – an increasingly important issue as huge swathes of old housing stock are revamped.

Our research has highlighted the need for architects, builders, housing providers, residents and healthcare professionals to work together to assess the impact of changes in housing quality and occupant behaviour, and we’re working closely with two Cornish companies to try and find some answers.

In collaboration with social housing provider Coastline Housing we’re working to understand how new building practices such as improved insulation and energy efficiency –intended to reduce energy use and fuel poverty – can affect occupant health.

Collecting data through questionnaires with residents and the detailed sampling of homes, we’re hoping to shed light on the complex mix of factors that affect indoor dampness, and to communicate best practice to reduce the presence of mould. This award winning partnership is at the cutting edge of built-environment research and has been expanded to include the innovative technology of a second Cornish company, Carnego Systems.

Carnego is helping the team by using its digital monitoring tools to collect real time data (such as temperature and humidity) on the indoor environment. As we attempt to broaden the study’s applications further, we’re also working with several other partners including Community Energy Plus and the Met Office – which will provide historical weather data to determine how external conditions can affect indoor air.

There’s no doubt that energy efficient homes have been an incredibly positive step in the evolution of the country’s housing stock. But the implications for dampness, mould, house dust mites and allergic conditions have been overlooked.

Failure to address these issues now poses future consequences for occupants’ health because of the continual need to achieve greater energy efficiency. The role of ventilation and its impact on health is often neglected and we are seeing more damp-related problems in homes that have been sealed to prevent heat loss.

We hope our findings will go on to inform the design of new houses, housing policies and health intervention work aimed at reducing the costs associated with maintaining the built environment, as well as the health and wellbeing of residents throughout the UK.

You can read more on this research by following the links below:

Richard Sharpe is a PhD researcher at the European Centre for Environment & Human Health. He has received funding from the European Social Fund Convergence Programme for Cornwall and the Isles of Scilly.