Welcome to NBS


Achieving sustainable domestic refurbishment

By Neil Storkes
Architect and NBS Technical Author

It has recently been stated that we need to upgrade 12,500 homes a week to hit the government's target of achieving an 80% reduction in CO2 emissions by 2050.

A recent survey of social landlords has indicated that up to one quarter are unlikely to have retrofit strategies in place for at least another five years, and that the 10 year deadline for achieving the Warm Homes Standard is likely to be a huge challenge, particularly at a time when funding for social housing is being cut.

In England, much government and industry effort is being directed to establishing how we can reduce energy consumption in our homes. Unfortunately, much of the UK's existing housing stock is old, very inefficient in terms of energy consumption, and will not be replaced within the foreseeable future.

The Centre for Alternative Technology report, Zero Carbon Britain 2030, states the following:

'The domestic sector accounts for 28% of total British energy demand. It is responsible for approximately 30% of Britain's total emissions. Over half of domestic carbon emissions are from space heating (53% in 2005), while one fifth comes from heating water. The remainder comprises of appliances (16%), lighting (6%) and cooking (5%).'

'The largest decrease in emissions from building stock will come from refurbishment. A Code for Sustainable High-Performance Refurbishment is required to ensure this is done to a high level and avoid it being done twice.'

The BRE Trust Report, Energy efficiency in new and existing buildings – comparative costs and CO2 savings, considers the relative impact on UK CO2 savings targets of constructing new zero-carbon buildings as opposed to improving the energy efficiency of the existing stock, in order to achieve the UK government's target to cut 1990 levels of CO2 emissions by 80% by 2050. The report states that:

'In Britain in 2005 there were over 9 million uninsulated cavity walls and 6.3 million lofts with little or no insulation (DCLG, 2007).

There is therefore an urgent need to develop a robust low or zero-energy strategy for refurbishment schemes. This can be achieved through design and energy efficiency measures, most notably an increase in insulation. For refurbishment projects a “whole house” approach is necessary. This means designing a strategy for the house rather than seeking incremental reactive improvement. The strategy needs to ensure that all existing dwellings are included. Unfortunately the current CERT scheme and most local authority schemes are very limited both in terms of their scope and the available funds. The CERT programme continues to spend several billions of pounds on home insulation and boiler upgrades.'

The Department of Energy and Climate Change's whole house three year energy efficiency programme, the Carbon Emissions Reduction Target (CERT), came into effect in April 2008, and is the third phase of a programme that has been running since 2002.

In conjunction with CERT, a large number of local authorities have developed local strategies to upgrade the level of thermal insulation in homes in their areas. Various other high-profile national programmes such as the Grand Designs Great British Refurb campaign, are actively promoting the upgrading of existing housing stock to try and reduce energy demand. Such work is typically limited to the installation of cavity wall and loft insulation, and the replacement of boilers.

In many urban areas, much of the existing housing stock comprises small Victorian or Edwardian terraces, with solid walls and rooms in the roof space. If the loft access has less than one metre of clear headroom at the hatch position, then contractors are not allowed to access these areas under restrictions imposed by current Health and Safety legislation. Therefore, due to the nature of their construction, it seems likely that many of these homes are likely to remain substantially untouched by these campaigns.

The government's Green Deal, which is due to commence in late 2012, is expected to offer a more flexible way of delivering building fabric improvements to our existing buildings, particularly those that are more difficult to deal with. However, the fact still remains that our existing housing stock is an eclectic array of different styles, materials and constructions, and there can be no 'one-fits-all' solution to building fabric upgrades. How do we deal with solid wall constructions other than cover them with insulated render, or force occupants to suffer the imposition of insulated dry-lining? Also, how do we persuade private landlords to make the necessary investments when they may suffer loss of income without being able to pass the cost onto their tenants, particularly when it is the tenants who will benefit from the reduction in energy bills?

In a recent article in Building (17 September 2010) 'Less really is less', Diana Ürge-Vorsatz, director of 3CSEP, Central European University, Budapest, suggests that:

'To maximise the energy-saving potential of the construction sector, the main emphasis needs to be on retrofitting existing buildings. However, most programmes cherry-pick ways to cut energy, resulting in no more than 15-40% savings in heating and cooling energy use. Changing the boiler, adding a few centimetres of insulation to part of the building envelope, replacing a couple of windows will not provide the best whole-building solution. Even when the efficiency of individual building components is optimised, the result is still less environmentally beneficial than when a systemic, whole-building retrofit is planned.'

The conclusion from the article is:

'Do it well or don't touch it. Policies and subsidy schemes should either support holistic, deep retrofits - or wait until this becomes possible - otherwise we seriously jeopardise medium- to long-term climate targets, or at least make them very expensive to achieve. Many governments in Europe and elsewhere in the world need to re-examine or reconsider their present policies supporting building refurbishment initiatives.'

Developing a 'Code for Sustainable High-Performance Refurbishment'

Refurbishment projects and particularly domestic refurbishments tend to be either:

  • Major refurbishments where a property or a series of properties are to be partially or completely 'gutted' and then reconstructed. This provides the opportunity to make major changes to the original building fabric and services
  • Minor refurbishments which can occur during routine planned maintenance or planned refurbishment projects. Minor refurbishment of multiple or single properties may include: replacement of roofs, windows and boilers; improved heating controls and ventilation; new water appliances (taps, toilets, baths etc.).

BRE are currently developing a BREEAM Domestic Refurbishment standard for issue during 2010-11. In the meantime, the only current low carbon design standards for upgrading existing domestic buildings are BREEAM Ecohomes (2006), BREEAM Ecohomes XB and Passivhaus.

BREEAM Ecohomes was initially designed to be used for new-build properties and those undergoing major refurbishment. Ecohomes was last updated prior to the introduction of the Code for Sustainable Homes (CSH) in 2007, and formed the basis of the CSH which is now used for all new-build domestic properties in England. The use of Ecohomes is now limited to new-build outside England and major refurbishment works. According to BREEAM guidance - 'because of the banding structure that Ecohomes uses - Pass, Good, Very Good and Excellent ratings - it is not suitable for more minor or localised refurbishment works (such as replacement windows or replacement of a roof) where small works would make only a small impact to the overall rating score.'

Those refurbishment projects that have successfully met the Passivhaus standard have also required a significant amount of reconstruction or new-build work. The main reasons for this are the very stringent thermal insulation, cold bridging and airtightness standards that need to be achieved for Passivhaus certification. In addition, BREEAM Ecohomes and Passivhaus certification do not allow incremental improvement and so can only be considered for complete or whole-house building refurbishment projects.

The only standard that can currently be used for minor refurbishment projects is BREEAM Ecohomes XB and, according to BREEAM guidance, this applies only to housing stockholders. These may be housing associations, local authorities or private companies that have existing housing stock.

Other than CSH, application of these standards is currently a result of either planning requirements or client choice. As most minor refurbishment projects are unlikely to involve the need for planning permission, there is a concern that many smaller projects will slip through the net and make no significant contribution to the 80% reduction in CO2 emissions reductions required by government by 2050.

If the government's commitment is to be achieved, the Building Regulations need to be urgently reviewed for refurbishment work, and brought up the levels set by BREEAM, CSH and Passivhaus. Unfortunately, the latest changes to Approved Documents L and F (England and Wales) seem to have drawn away from imposing significantly higher standards for existing building fabric associated with refurbishment and alteration projects.

A speaker at the recent BEST Show in Birmingham stated that:

  • A recently commissioned survey of newly completed houses has indicated that up to 1 in 2 of those properties have not been constructed to their design standards
  • 1 in 3 recently completed non-domestic buildings do not have a completed Energy Performance Certificate when they are sold or leased, despite this being a legal requirement.

Significant concerns were expressed about our reliance on increased Building Regulations standards when those regulations are not being effectively policed and enforced!

A recent report (Building magazine – 4 November 2010) by a team from Leeds Metropolitan University on a new-build low-carbon housing scheme in York (by the Joseph Rowntree Housing Trust) has identified various problems including:

  • Heat loss levels at 54% higher than design levels
  • Operational problems with solar hot water systems
  • Significant underperformance of heat pumps.

A major concern is that if large parts of the construction industry do not have the wherewithal to deliver new low or zero-carbon buildings (that do what they say on the box), how will that same industry deliver effective low or zero-carbon refurbishment? Whilst off-site construction may ultimately be a way forward for achieving the required standards for new-build projects it cannot solve the problems for existing buildings.

It seems likely that no amount of financial investment or incentive will deliver the zero-carbon built environment that is demanded, and that whatever improvements can be made must be balanced with achieving a low or zero-carbon energy infrastructure. This will need to embrace 'popular' options such as nuclear power and large-scale wind farms, together with local power generation through PV installations on public buildings and privately owned domestic south facing roofs.

And finally

BREEAM, CSH and Passivhaus all include the specification of energy efficient white goods within their assessment programmes but currently exclude other consumer electrical items.

In the period from 1970 to 2006 the average UK SAP rating for new domestic buildings increased in efficiency by about two and a half times, and in the same period domestic energy consumption increased by 18%. Analysis of data suggests that whilst energy requirements for space heating fell, there was an increase in consumption due largely to the more prevalent use of computers and other electrically powered items.

It has been suggested by some that this is a cultural as well as an environmental issue, and that the best way to encourage a reduction in energy consumption is by an energy tax related to level of consumption, with discounts available to those who consume less, so that conserving energy becomes part of a way of life rather than just a way of building. The main concern with such a strategy is that it is likely to penalize those who have least opportunity to upgrade their homes and can least afford the penalty. With this option, fuel poverty is likely to become an ever increasing problem.

So in the meantime, if this is cultural as well as environmental, we need to persuade people that if they've got TVs, computers, games consoles, mobile phone chargers and all the other electronic paraphernalia and they're not using them, please turn them off and don't leave them on standby all night – and that applies at home and at work. It might just help!.

Related NBS information:


Selected links:

Written November 2010




Email Updates

Receive regular email
updates from NBS

Follow @TheNBS on Twitter

Buy now

Rough Guide to Sustainability: A Design Primer (4th Edition)

Retrofit for Purpose: Low Energy Renewal of Non-Domestic Buildings

Available now from
RIBA Bookshops


Sustainability Blog

To keep up to date, read the
NBS Sustainability blog