Sarah Harrison, ‘Superhome’ owner, London

Although new homes in the UK have increasingly low CO2 emissions, there are 26 million existing homes, five million of which were built before 1945.

The Sustainable Energy Academy (SEA) has set up the ‘Old Home Superhome’ programme to spread awareness of the ways in which household CO2 emissions can be reduced by 60- 80%, even in hard-to-treat homes; to inspire people to make similar changes to their own homes; and to influence policymakers to set the policy framework to make it easier to do so.

Context

About 27% of UK CO2 emissions are due to housing. Although new houses are built to increasingly tight standards of energy efficiency, there are about 26 million existing homes. If national targets for reducing carbon emissions are to be met, then existing homes need substantial improvement. 20% of existing homes were built before 1919, and 38% before 1945, and an estimated nine million are classed as ‘hard-to-treat’, because they have solid walls or another structural property that makes them difficult to insulate.

Many households are aware of only a few options for reducing their CO2 emissions, such as cavity wall insulation, loft insulation, double-glazing and low energy light bulbs. However, these measures alone do not usually deliver the 60 to 80% cuts that are required to reduce the risk of climate change.

Double-glazing can significantly increase the energy efficiency of old homes without spoiling their character

The Sustainable Energy Academy (SEA) is running the ‘Old Home Superhome’ programme to demonstrate that it is possible to achieve 60 to 80% CO2 emission reductions in older houses, including those classed as hard-to-treat. SEA has recruited 28 homes into the programme, each of which has reduced its carbon emissions by at least 60%. SEA increases public understanding of what can be achieved in existing homes, by helping owners to open their homes to the public on a regular basis. SEA aims to inspire visitors by providing a ‘touch and feel’ experience that gives them confidence to take action.

How the programme works

The goals of the Old Home Superhome programme are to spread awareness of the ways in which household CO2 emissions can be reduced by 60-80%; to inspire people to make similar changes to their own homes; and to influence policymakers to set the policy framework to make it easier to do so. In order to achieve these goals, SEA aims to create a network of 200 homes across the UK that have achieved these CO2 reductions and are open for the public to visit.

28 homes have been recruited into the programme so far, using contacts in environmental groups and local councils. Homeowners are given training on how to plan and run an open day at their home, and support on the days they are open. Most homes open periodically, typically for two to four days per year, and SEA organises publicity to ensure that there are plenty of visitors. On the open day, visitors are led round the home in small groups while the owner explains the changes made to the house and answers questions. Some of the houses in the programme are not occupied, but are council owned and used as demonstrators. SEA refers to these as EcoHouses rather than Superhomes, and they are open much more frequently, often several days per week.

An efficient wood-burning stove is an effective low-carbon heating solution in old homes

Technology and use

Most of the Superhomes are Victorian or Edwardian, with solid wall construction. Because each Superhome owner has made their own decisions about the changes to be made to their home, there is a diverse range of technology installed. The technologies used are described below, grouped into those related to heat and those related to electricity. In each group, energy efficiency work is generally undertaken before any energy generating equipment is installed.

Heating

  • Where possible, cavity wall insulation is used. Where walls are solid, external or internal insulation is used instead.
  • Some households with wooden floorboards have taken up the floor and filled the space underneath with insulation, sealing against draughts when replacing the floor.
  • Draught-proofing is carried out on windows, doors and loft hatches.
  • High specification double- or triple-glazed windows are installed, using argon-filled spaces and low-emissivity coatings on the glass.
  • Once a house has been draught-proofed, ventilation comes through controlled vents. In some homes a heat recovery unit has been installed, extracting heat from air being expelled and using it to warm incoming air.
  • Several households have had solar thermal panels installed, to use the sun to provide part of the household’s hot water demand, typically 50%.
  • For space heating, some households have installed a wood-burning stove that can take logs, or a boiler burning wood pellets. Others have installed heat pumps, which use the ground or a river as the heat source.
Several households have had solar thermal panels installed

Electricity

  • Several households have installed ‘sun pipes’, which use a reflective tube to bring sunlight from a roof-mounted window into a dark corner inside the house, reducing the need for lighting during the day.
  • When lighting is required, all the households have used efficient bulbs, including a range of fluorescent and LED types.
  • For generation of electricity, some households have installed solar photovoltaic modules or small wind turbines.

How users pay

All Superhome owners have paid for the improvements to their homes themselves, where possible getting a grant from the Low Carbon Buildings Programme (LCBP) for installation of renewable energy technology. However, many owners have found the LCBP difficult, because of the frequent changes made to it.

The cost of the major measures used is typically £8,000 for solid wall insulation; £5,500 for double-glazing and draught-proofing; and £3,500 for solar water heating. The total cost of upgrading to ‘Superhome’ performance obviously depends on the measures used, but is typically between £15,000 and £25,000. This is a significant outlay for a homeowner, although only a small percentage of the total cost of the house.

The Superhome owner is offered a small payment by SEA when they have an open day, and entry is free for all visitors.

Wall insulation

Training and support

To prepare Superhome owners for hosting open days, SEA trains them in speaking to groups of people and helps them plan the day. During the open day SEA staff and volunteers come to help, and also give further ‘on the job’ training to the homeowner. SEA also assists by preparing marketing materials, including posters, displays and leaflets for people to take away.

Aside from the actual open days, SEA helps the Superhome owners by holding regular meetings where they can share ideas, and by providing a website forum for online discussions. SEA also handles all the publicity needed to advertise open days.

Benefits

Since the Old Home Superhome programme started in 2007, the homes have received over 36,000 visitors, including government and council officials who are in a position to influence policy.

Environmental benefits

Most homes were upgraded at the time the owner moved in, so no data is available on previous energy use. ‘Before’ and ‘after’ CO2 emissions are therefore estimated using standard NHER assessment techniques. Where complete data is available, it has been found that the CO2 reductions achieved are usually higher than estimated, which suggests that owners reduce energy use through behavioural change as well as through changes to the fabric of their homes.

Logs for wood-burning stove

Based on the standard estimates, all Superhomes have reduced their carbon emissions by at least 60%, which is the condition for joining the network. The average is a 70% reduction and one has become carbon neutral. The 28 homes in the programme at present give a combined emission reduction of 186 tonnes/year CO2, or an average of 6.24 tonnes/year CO2 per home. Many homeowners also practise water conservation and some have added rainwater harvesting to their homes, using the water for gardening and toilet flushing.

There is also a reduction in CO2 emissions due to changes made by people to their own homes as a result of visiting a Superhome, but these are difficult to quantify. SEA has carried out two small surveys to find what visitors intended to do, and these suggest that a visit to a Superhome results in carbon savings of about 0.09 tonne/year CO2 per visitor. If this estimate is reliable, then reductions of over 3,000 tonnes/year of CO2 have been achieved by the 36,000 people who have visited so far. SEA is now carrying out more systematic surveys of visitors. It is also working to encourage major retailers of energy efficiency technology to offer discount vouchers to people who visit Superhomes.

Social benefits

For the Superhome owners the immediate benefits of the work they have done in their homes are reduced energy bills and warmer, lighter homes. They have also benefitted from their involvement with SEA, as they enjoy opening their homes to help encourage visitors to emulate them, and have gained confidence in public speaking. Although all had taken action to reduce carbon emissions before they joined the network, they still value the contact with other network members and learn from them.

However, the Superhome visitors are the more important group. They benefit from seeing that it is possible to dramatically reduce the carbon emissions of any home, no matter how it is constructed and where it is located. They see a range of technologies and options, from the complex to the simple. They can hear about the benefits directly from the person who installed the technology and lives with it every day, rather than from someone who is just  promoting a cause. They discover that reducing the carbon emissions of a home does not need to make it ugly or awkward to live in, and can save them money in the long run. In many homes they will also see that the renovations can often be implemented one step at a time, making the process more practicable and affordable.

For space heating, some households have installed a wood-burning stove

Economic and employment benefits

At least five Superhome owners work in businesses related to housing or sustainable energy, and their involvement with the Old Home Superhome programme brings them into contact with potential customers. Some of them have renovated their homes specifically to serve as showcases for the services they offer.

Potential for growth and replication

The scope for replication by visitors is huge, as there are millions of homes that could be improved using the technologies demonstrated in the Superhomes. At present there are two barriers to replication: complexity and cost. The Superhome owners are early adopters of some of the technologies, but are highly motivated and prepared to learn what they need to make them work. Not all the visitors have the same experience and passion, but the work done in the Superhomes will make the technology easier for people to understand and mark out a path they can follow. 

Cost can be a barrier because although significant cuts in carbon emissions can be achieved by cheap measures like cavity wall and loft insulation, going further starts to cost more. However, some of the Superhomes demonstrate how renovations can be made gradually to a house, spreading the cost out over time.

One of the key benefits of the Old Home Superhome programme for replication is the learning that it provides for policymakers. The programme shows convincingly that it is possible to make radical reductions in CO2 emissions at the household level. It also shows a range of practical ways to achieve these reductions. The detailed, practical knowledge of Superhome owners, and their experience of existing UK policy, is invaluable for guiding policy to support similar carbon reductions across all the existing building stock, and help meet the CO2 reduction targets that the UK has set.

SEA Superhomes are now twinned with the Sustainable House Day in Australia, and are discussing being twinned with a similar programme in Germany, bringing new opportunities for sharing expertise and generating publicity.