Adapting homes to overheating
Back in December 2014, 75 housebuilders, social landlords, architects and others representing 208,047 homes in the UK participated in our survey, produced with the Zero Carbon Hub, on overheating in homes. The survey asked participants to describe, for example, how they define and assess overheating risk in residential properties. It also asked those responding to say what was motivating them to take action. Customer satisfaction came high on the list. Other incentives included having had overheating problems in the past, and the presence of local authority requirements in Local Plans.
There are, however, few official triggers or requirements to drive action in this area. One, the SHIFT sustainability standard for Registered Providers, requires participating organisations to carry out overheating risk assessments as part of a broader policy to ensure properties are suitable for a changing climate.
Two questions in the survey were dedicated to understanding whether Housing Providers are specifying requirements in contracts with their supply chains, intended to adapt homes to overheating. The majority of respondents reported that they currently do not.
Those who do, use a variety of methods including:
- Requiring contractors to carry out dynamic thermal simulation modelling.
- Requiring contractors to use passive shading measures
- Ensuring Passive House Planning Package (PHPP) targets are used
Advice to occupants
In terms of education and behavioural change, over a half of respondents (62%) stated that they provide advice directly to occupants on how they can keep their properties at comfortable temperatures. The advice is included in the Home User Guide and/or occupant handbook or is provided in face-to-face briefing sessions. Examples of the advice given relates to:
- Using MVHR system and heating controls correctly
- Using lighting, heating and hot water systems properly
- Use of energy-efficient appliances to avoid excessive internal gains
- Use of natural ventilation to cool indoor spaces and shading to reduce heat gains.
Adapting buildings and designs
Overheating occurs when too much heat builds up inside a dwelling which cannot be adequately “purged” or rejected. Heat can come from a number of sources inside or outside the building. As an overall strategy, experts advise Housing Providers to:
- Limit the amount of heat coming into a dwelling in the summer as much as possible using the design of the building and passive measures such as shading devices
- “Reject heat” that has built up inside the property by ventilating, passively cooling, or potentially in challenging cases, by actively cooling
- If possible, use the thermal mass of the building to store excess heat and smooth out peaks in temperatures – as long adequate ventilation is also provided to ensure the heat in the building materials in removed regularly
- Provide advice to occupants to help them stay cool and make the most of the building’s design
During the construction of a building, there are significant opportunities to minimise overheating. Similarly, during a major refurbishment projects, the building form and orientation is usually set, but there may also be opportunities to make significant changes such as replacing windows, changing the internal layout, or providing better ventilation. During a simple retrofit, options would usually more limited.
However, action taken to trigger behaviour change is often just as important in adapting to overheating using the physical design of buildings. In the social housing sector the education of residents and the occupant’s interactions with the building form an essential part of efforts to reduce energy and limit overheating risk.
For more information on solutions to overheating see the Zero Carbon Hub’s “Solutions to Overheating in Homes Evidence Review”, published on 31 March 2016. Visit www.zerocarbonhub.org