Residential: fuel poverty, energy efficiency and health

Studying the links

4 November 2015

Jan Ambrose looks at ground-breaking research into the relationship between fuel poverty, energy efficiency and health

The University of Exeter Medical School’s European Centre for Environment and Human Health has conducted comprehensive research into energy efficiency, fuel poverty, indoor air quality and health. Its findings have been published in various medical and environmental journals.

The modern energy-efficiency mantra dictates that we build new homes to increasingly stringent regulations. Additionally, retrofitting existing properties is now a key strategy in the UK to meet energy and climate change targets, as well as protecting against cold-related illnesses. Greater insulation and sealing properties to prevent heat loss can help those in fuel poverty, particularly, which is a public health problem affecting around 2.4 million homes in the UK.

Undeniable benefits

Although insulating homes has undeniable benefits for heating bills and CO2 emissions, the Exeter report questions the impact on the indoor environment where such factors as heating, ventilation, people’s behaviour and the type, orientation and geographic location of a property, all affect air quality. It argues that over recent years, there has been a rise in allergic diseases that cannot be explained by factors such as genetic changes alone. One in three people in industrialised countries is now suffering from allergies.

The UK has one of the highest occurrences of asthma in the world, with the disease presenting substantial economic and societal pressures. There is now an increasing focus on indoor air quality to explain this. Evidence suggests that rates of allergic and respiratory disease are linked to poor indoor housing conditions and lack of ventilation. Yet no study has been able to assess how increasing household energy efficiency may impact the health and wellbeing of people living in homes with inadequate ventilation and mould growth.

The report critically reviewed the findings from 17 studies in 8 different countries and found the presence of several types of mould can lead to breathing problems in asthma sufferers, significantly worsening their symptoms. Although research in this area is still in its infancy, it looks as though mould may actually trigger the development and exacerbation of asthma. With more than 10 varieties found in a typical home, most people may not be aware that moulds are abundant in outdoor and indoor environments. Where a house or flat suffers from damp (such as condensation and penetrating damp), there is an increasing incidence of mould.


The structural integrity and architectural design of a (typically old) building can often lead to water making its way inside. Lack of ventilation and heating can then increase the indoor humidity, with this moisture ultimately condensing on cold surfaces and promoting the growth of mould.

Increased household energy efficiency can benefit health and make heating a property more affordable. 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 currently affects around 16% of European dwellings.

The extent to which a home is heated and ventilated is largely controlled by the habits of its occupants, and the way they live varies hugely. For example, some 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.

Efforts to prevent heat loss by reducing ventilation have led to undesired consequences for indoor air quality

All these behaviours can increase the humidity and dampness in a home, with poorer families in particular less likely to maintain adequate ventilation in winter, often failing to heat the whole building.

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

Working together

The research has highlighted the need for housing providers, residents and healthcare professionals to work together to assess the impact of changes in housing quality and occupant behaviour; the team collaborated with a social housing provider to understand how new building practices intended to reduce energy use and fuel poverty, such as improved insulation and energy efficiency, can affect occupant health.

It then conducted a study based on 700 social housing properties in Cornwall to examine how poor air quality and dampness can affect the health of people living in energy-efficient homes, and the potential impact occupant behaviours and fuel poverty may have on the indoor environment. It found that greater household energy efficiency represented a higher risk of asthma, but at the same time lowered problems with indoor mould contamination.

There are a number of potential explanations for these findings, but the research team believes that a failure to heat and ventilate the home is likely to lead to exposure to dampness-related pollutants. The study pointed to other possible factors that can affect health in homes with high humidity, such as different types of moulds, house-dust mites and bacteria, as well as biological, chemical and physical pollutants not assessed in this study. While greater insulation in energy-efficient homes reduces the risk of condensation, this may be impacted by fuel poverty where people may make choices about the way they heat and ventilate the home to reduce fuel bills.

Fuel-poverty behaviours

An additional analysis focusing on fuel-poverty behaviours found that around a third of the study population did not heat the home due to the cost of fuel, which resulted in an increased risk of damp and mould contamination. These remained, despite occupants’ perception of the potential health risks resulting from living in mouldy homes and their heating and ventilation practices.

It also found that participant age, occupancy, socio-economic status, pets, drying washing indoors, geographic location, architectural design/age of the property, levels of insulation and type of heating regulated risk of mould contamination. Further work is required to assess the complex interaction between occupant behaviours, risk perception, the built environment and the effective use of heating and ventilation practices.

The extent to which a home is heated and ventilated is largely controlled by the habits of its occupants, and the way they live varies

The complexity of the relationship between indoor environmental exposures and resultant impact on health was also evident in another study focusing on a representative sample of the US population. Here, the researchers found that exposure to a mouldy home represented a risk factor for people suffering from eczema, allergy and asthma. However, the study also found that allergic sensitisation may play a different role in children and adults who are exposed to indoor moulds, and that exposure to multiple allergens (pet, moulds, house-dust mite and endotoxin) may reduce the risk of atopic disease in some populations.

These findings support the notion that differences in lifestyle characteristics, communities and their interaction with the natural and built environment are important in regulating health status at the population level.

Complex factors

The researchers also collected data from residents and conducted detailed sampling of homes in an attempt to shed light on the many complex factors that affect indoor dampness and to reduce the presence of mould. Cornish company Carnego Systems is assisting the team by using its digital monitoring tools to collect real-time data (such as temperature and humidity) on the indoor environment. Other partners will also be involved, including independent energy specialists, Community Energy Plus and the Met Office; the latter will be providing historical weather data to determine how external weather can affect indoor air conditions.

The studies, published in the journal Environment International and Clinical and Experimental Allergy in 2015, raises questions about the way energy efficiency improvements are made and the importance of ventilation in UK and US populations. It represents the first time detailed asset management data has been combined with information about occupant behaviour and health, to assess the factors likely to contribute to asthma. There are still many questions to address.

There remains a need to address the effectiveness of current ventilation methods and the role of occupant behaviours

It is vital that the energy efficiency of homes continues to be improved, thus making them more affordable to heat and reducing the carbon footprint of the domestic sector. However, there remains a need to address the effectiveness of current ventilation methods and the role of occupant behaviours. For example, future work needs to consider how ventilation systems cope with the requirements of different types of buildings (e.g. houses versus flats), fluctuating occupancy rates and changes in behaviours, which may include the use of different types of mechanical ventilation systems.

Focusing on social housing enabled the team to explore a wide range of buildings, from traditionally stone-built properties through to retrofitted homes and newbuilds. It was unable to explore homes with a SAP rating of >88, which should be assessed in future work. A better definition of energy efficiency is needed to overcome some of the limitations of current work.

SAP methodology

The current SAP methodology does not account for variations in occupant behaviours and the actual day-to-day performance of a property is likely to differ from its predicted energy efficiency. Consideration should be given to the type of ventilation system installed, which can increase indoor humidity. This problem may be worsened by the type of heating system and the energy-efficient method used to seal cracks and gaps.

Without doubt, 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. Hopefully, ultimately the research findings will inform housing policies and health intervention work aimed at reducing the costs associated with maintaining the built environment, and improve the wellbeing of UK residents.

Jan Ambrose is Editor of the Residential section of the RICS Property journal

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