Overheating is a necessary discussion in the UK’s drive for zero carbon housing

As the push for increased zero carbon housing intensifies and the Government’s 2016 zero carbon target nears; the growing issue of overheating needs to be taken on board by today’s house-building industry.

Reported cases of overheating in existing dwellings are still relatively low.  However, enhanced construction methods, higher standards of airtightness and increased thermal insulation in new homes are undeniably causing indoor temperatures, in some instances, to reach uncomfortable levels during summer months.  And for vulnerable groups, such as the elderly, overheating risks harming occupants’ health.

Overheating is caused when homes struggle to expel heat, often built up as the result of a mixture of normal occupant activities and high external temperatures.  And in the latest report from the NHBC Foundation, Overheating in New Homes: a review of the evidence, it finds that overheating is no longer an issue confined just to a few very hot summer days but is now something potentially affecting homes for significantly longer periods.

Building on industry guidance published last year Understanding overheating – where to start: An introduction for house builders and designers, this latest report looks at the issue in more detail.  Considering the issue from the perspective of impact and health concerns, the report calls for a universal definition of overheating in dwellings and clear national thresholds.  These thresholds will enable planners, designers and authorities to tackle overheating while striving to build and deliver more energy efficient homes.  If left unchanged, the potential risk to the health of occupants, especially in vulnerable groups, could become an increasingly significant concern.

While there is a reasonable amount of research on high external temperatures and their effect on humans, less is known of the effects of indoor temperatures on health and well-being.  From a health perspective with increases in climate change, a strong zero carbon agenda and an ageing population, it’s highly likely that the number of reported cases of overheating will increase in the future if this problem is not tackled head on today.

The insulation performance gap and what it means for zero carbon targets

There are just four years left until the zero carbon homes policy comes into full effect.  And with the findings of a previous report, Low and zero carbon homes – understanding the performance challenge, published by the NHBC Foundation, it’s clear more needs to be done to address the performance gap where ‘as-built’ differs from the ‘as designed’ performance.  The research identified a number of potential causes of this gap and highlights the under-performance of materials and systems used in new homes.

More recently the NHBC Foundation contributed to a report by the BBA (British Board of Agrément) on roofing insulation materials and how to reduce the performance gap.  Entitled Air movement & thermal performance the report investigates the effect of air movement on the performance of roof insulation.  The project involved using a large-scale rig specially constructed to replicate real life installation of various roof insulation materials.

The research finds that thermal insulation performance is affected significantly by air movement.  Air gaps present in the construction, create enough air movement  to significantly reduce the effectiveness of thermal insulation. The U-value of those roof constructions tested increased by up to 80% at higher wind speeds.

In order to help reduce the U-value and close the performance gap the report makes a number of recommendations including developing more guidance on workmanship; this should help the industry to understand how to optimise the performance of the structures it is building.  Furthermore, coupling this with robust thermal design techniques should help dramatically improve thermal performance of insulation.

While the BBA’s project concentrates on roof insulation, it may have implications for insulation performance in other applications, such as in walls and floors.  It would seem probable that a similar performance gap could also occur in these applications too.

Further research with the aim of resolving this issue will be vital in achieving the 2016 zero carbon target; failing to do so could create housing that is ‘theoretically’ low carbon but which in reality is far from it.

Change attitudes today to save energy in the future

Last Thursday saw the long-awaited Energy Bill published, setting out the Government’s approach to the future, low carbon economy.

Several measures were proposed to boost investment in nuclear and renewable energy by £110bn in 2020, alongside an additional proposal to incentivise electricity reduction across homes, businesses and industry.  

Among these measures was the increase in the green levy to support growth of low carbon electricity from £2.3bn today to £7.6bn a year by 2020. This measure was initially reported to increase household energy bills over the same period but The Department for Energy & Climate Change’s announcement later claimed that the Government’s energy policy would actually keep household bills down over the long run – with bills 7%, or £94, lower by 2020.

While the precise effect on consumers still remains unknown, the reality is that a move towards renewable energy more generally will require a shift in consumer mindset about energy consumption regardless.  As figures also released last week by uSwitch showed a 63% rise in household energy costs over the last five years – with the average annual bill hitting £537 – the need for consumers to review energy efficiency in their homes can no longer be ignored.

However, to achieve this awareness and action will require greater education on the issue. As The NHBC Foundation found in its most consumer research report earlier this year, Today’s Attitudes to Low and Zero Carbon Homes (NF40), far more needs to be done to educate the public on the benefits of moving to a low carbon energy system and increase interest in energy efficient living.  For, as calculations show in our past blog post, Energy Efficient Homes Could Cut Annual Bills in Half, the potential monetary savings in low carbon homes are significant and higher energy prices tomorrow can be hedged by smart use of low carbon technologies today.

With the first deals of the Green Deal available from 28^th January next year and gaining momentum, the appetite for homeowners to reduce their energy consumption is evident. While change will not happen overnight, the Energy Bill does emphasise the fact that changes will have to occur if energy is to be conserved and created for future generations.

Skills agenda must remain top priority to meet zero carbon targets

Ahead of Peter Hansford’s appointment next month as the Government’s new chief construction advisor, the former president of the Institution of Civil Engineers has set out his priorities for the sector looking ahead to 2013. Taking over from Paul Morrell who has held the role for over three years, Mr Hansford has made clear his desire for a concerted effort to bring about cost and carbon reduction in construction and improvements in skills and innovation in the industry.

As we previously blogged in January, NHBC Foundation recognises that in order for the Government’s low carbon targets to be achieved by 2016, it is vital that installers are properly trained and equipped to complete the task ahead. Knowledge of correct installation techniques will be essential in delivering emission reductions in both energy efficient, new-build homes and existing properties too. By ensuring the focus remains on improving skills, we can help to create a workforce capable of delivering better housing stock across the UK.

Simple communication of often quite complex design specifications will form an essential part of this process. Educating installers and end users is something the NHBC Foundation recognises as a vital element of the wider carbon reduction effort and we regularly produce research and guidance to do just that. The Part L 2010 – where to start and Part F 2010 – where to start guides offer a good example of where we have looked at some complex regulation changes and briefed these to the sector in an easy-to-use format. The guides explain some of the relevant terminology, and provide a broad understanding of the changes to both Approved Documents, pointing the builder and designer towards data that must be consulted as well as requirements for installation and commissioning.

Greater collaboration between industry and the Government needs to be taken to ensure that the 2016 zero carbon targets are met on time. The consumer incentives offered to kick start the shift towards renewable living represents only half the battle. The real challenge lies in assisting installers across the housebuilding industry to develop the necessary skills so that green technologies function as they were designed to.

Occupant behaviour focus of new energy efficiency strategy

This week, the Government made a major announcement on new energy efficiency measures, aimed at reducing overall carbon emissions and promoting more sustainable living across a number of areas including housing, retail and the public sector.  The new strategy, which the Energy and Climate Minister Greg Barker has championed as a way of transforming the way we use energy in the UK, is said to place energy efficiency at the heart of the Government’s overall energy policy.

As part of the new proposals, the housing industry will be the focus of substantial research funding looking at the way households consume energy.  

Under a £39 million initiative, five centres examining business and household energy demand known as “End Use Energy Demand Centres”, will examine what drives energy demand and how occupant behaviour might be influenced in future.

Occupant behaviour is an important area of consideration that the NHBC Foundation itself has previously explored through in-depth research.  In its publication The impact of occupant behaviour and use of controls on domestic energy use, NHBC Foundation looked at existing studies on occupant behaviour and user interface design in an effort to develop a more accurate picture of energy consumption in domestic households.

This review cited the importance of providing homeowners with the relevant information to understand how low carbon, energy efficient technology can work to minimise usage. Recommendations were also made for smart meters and other home displays to play a more prominent role in new-build housing stock, to better inform homeowners of where they currently use energy.  By providing a more visual representation of their consumption, we believe homeowners will reconsider how they heat their home and power appliances in future.

Other strands to yesterday’s strategy announcement include the implementation of an energy efficient labelling trial between the retail giant John Lewis and the Department for Environment and Climate Change.  This new labelling system will display the lifetime running costs of household appliances.  Our research published earlier this year, Today's attitudes to low and zero carbon homes, gauged the thoughts and opinions of occupants on the running of their homes, and with 68% already taking steps to reduce their carbon footprint, a visible labelling system that demonstrates potential energy savings could see that figure rise.

The Government’s latest step to try and boost efficiency measures and encourage homeowners to adopt more energy efficient lifestyle choices is a positive one.  But what is required now is for more detail on how this strategy for less consumption will be achieved, including a timeline of deliverables.  With important targets approaching fast, such as the requirement for all new homes in England to be carbon neutral by 2016, it is important that we act now to reduce our carbon footprint.

Incentives to improve energy efficiency

Over the past couple of years NHBC Foundation has been proactive in providing information to the house building industry and homeowners alike on the subject of energy efficiency in new homes. As news and events over the past couple of weeks of colder weather have shown, rising energy bills are again becoming a common concern for today’s homeowners.

We are therefore interested to hear about the latest initiative announced under the wider Green Deal to further incentivise change in this area.

From the 28th January 2013, homeowners will be encouraged to make changes to their home, such as improving insulation and double glazing. Participants will be able to claim cash back from a Government £125 million pound pot for the scheme, and the Department of Energy and Climate Change state that early adopters could receive as much as £1,000 from the scheme.

Research carried out by NHBC Foundation in 2011 and published in Today’s attitudes to low and zero carbon homes indicates that where savings can be quantified or financial incentives provided, there appears to be a willingness to improve a home’s energy efficiency.

Although awareness of the Green Deal at the time of the survey was relatively low, we hope that with ever increasing consumer awareness about the subject of a home’s energy efficiency and potential running cost savings, the initiative will effectively reward homeowners for making changes.

Spotlight on green issues aims to raise global awareness of the importance of sustainable living

Last month saw the launch of World Green Building Week, an event aimed at highlighting the awareness and role of buildings in conserving resources, saving money and creating jobs while providing healthier places to live, work and play. Former footballer Gary Neville spoke at a recent event to discuss sustainable design issues as he embarks on his own quest to build an eco-friendly home designed to meet the UK's highest environmental performance standards.

The aim of World Green Building Week is to help transform the global building industry and increase awareness of the importance of sustainable design methods.  This primarily involves profile-raising for the green building industry generally but such a campaign certainly strikes a chord with the UK housebuilding industry.

At the forefront of the drive to deliver low carbon, new-build housing stock, the UK house building industry is pioneering many innovative solutions to reduce emissions output.  And since 2006, NHBC Foundation has undertaken research and provided information and guidance to assist the house building industry meet its challenges, leading up to the Government’s 2016 target for zero carbon new homes.  To date, NHBC Foundation has published over 40 research and guidance reports on topical subjects to support industry challenges leading up to the Government’s 2016 zero carbon homes target.

One of NHBC Foundation’s recent research reports Today’s attitudes to low and zero carbon homes, published earlier this year, assessed the awareness and understanding of climate change and energy efficient homes amongst housebuilders, housing associations and home occupiers. One of the key findings was the need for improved understanding of exactly what a zero carbon homes is likely to be, given that the definition has been subject to much change.

The research found that in most cases, the house building industry say they understand the current version of the zero carbon policy, but there appears to be confusion around much of the detail and the associated costs of construction. From a consumer perspective, there is some scepticism about the term 'zero carbon', as well as some difficulty in understanding the number of complex terms often associated with low carbon technologies.

Much like the aim of World Green Building Week, the eleven recommendations of the NHBC Foundation research and much of the continued work of the Foundation highlights the importance of gaining consumer buy-in and understanding if the important role that homes can play in facilitating the move to a low carbon lifestyle is to be realised.