The drive for energy efficient homes is increasing asthma risk, finds a team at the University of Exeter Medical School. People are so concerned about energy savings they end up with homes that are not properly heated or ventilated, which could lead to more people developing asthma.

Working with a UK social housing provider, Coastline Housing, the research team assessed data from the residents of 700 properties in Cornwall. They found that people living in more energy efficient homes had a greater risk of asthma, and that the presence of mold doubled this risk.

This study, published in the journal Environment International, builds on previous work showing that dampness and mold can increase the risk of allergic diseases. It is the first time scientists have been able to combine detailed asset management data with information about occupant behavior and health, to assess the factors likely to contribute to asthma.

The United Kingdom has one of the highest occurrences of asthma in the world, with the disease presenting substantial economic and societal pressures. With the government releasing £30 million of funding this week for energy efficiency improvements, this study highlights the need for changes in the behavior of residents benefiting from this type of scheme.

Researcher, Richard Sharpe, has been involved in the study and said, "We've found that adults living in energy efficient social housing may have an increased risk of asthma. Modern efficiency measures are vital to help curb energy use, and typically prevent heat loss through improved insulation and crack sealing. Yet some people, particularly those living in fuel poverty, are unlikely to heat a building enough - or ventilate it sufficiently - to prevent the presence of damp and mold, factors that we know can contribute to asthma."

The presence of mold was unable to fully explain the study's findings however, with poorly ventilated homes also likely to increase people's exposure to other biological, chemical and physical contaminants. The study pointed to other possible factors which can affect health in homes with high humidity, such as house dust mites and bacteria.

Occupant behaviors often vary dramatically in different properties, with some people drying washing indoors or relying on older and less effective heating systems. These behaviors can increase the indoor humidity at a property, a problem which is sometimes worsened by energy efficient efforts to seal cracks and gaps.

Head of Technical Services at Coastline Housing, Mark England, said, "Energy efficiency measures are vital to help keep costs low and reduce the environmental impact of heating our homes. This research has given us an invaluable insight into how the behavior of people living in fuel efficient homes can affect health. As a result, we're working to provide better information to customers on how to manage their indoor environment, including potential training of volunteer sustainability champions."