Recent debates about creating a low carbon economy in the UK have been dominated by how we should generate energy in the future. However, meeting the low-carbon challenge will require us to spend just as much time thinking about how we can use less energy - which means focusing on buildings, not just power plants and turbines. 

Buildings represent a significant opportunity for carbon abatement in the UK - the energy we use in them is responsible for almost half of the country's CO2 emissions. In as much as the policy debate on energy is focused on buildings at all, it tends to revolve around domestic buildings. However, non-domestic properties have an important role to play too, given that they make up 18% of the UK's CO2 emissions and use 300TWh of energy per year, which is equivalent to the primary energy supply of Switzerland.

Realising savings from non-domestic buildings can be done economically, using options that exist today. Carbon Trust research has found that a 35% CO2 reduction by 2020 can be achieved using cost-effective measures. These would yield a net benefit to the UK of at least £4bn, while reductions of 70-75% by 2050 can be achieved at no net cost.

Although the opportunities are attractive, achieving them will be a challenge. Up to 2020, almost all possible cost-effective energy-efficiency measures will need to be implemented - requiring significant refurbishment of the building stock, in addition to wider grid decarbonisation and the presence of on-site, low-carbon electricity generation. More expensive measures will be needed beyond 2020, as we will have to do everything we can in order to meet our 80% reduction targets.

Improvements are necessary in both the 'kit' in buildings and in how they are used. Not only will the properties themselves need to perform better, they also need to be used more efficiently - as the average Display Energy Certificate (DEC) rating needs to improve by about four grades, from an average of E in 2009 to A in 2050, if the UK is to meet its carbon targets - which will require significant behavioural changes. 

Research commissioned by the Carbon Trust suggests that public sector buildings - including central government and local authority buildings - and various services contribute between 2.3% and 3.4% of the UK's CO2 emissions. The public sector has a clear leadership role to play, not just in driving these savings by reducing emissions from its own estate, but also in accelerating market activity across the sector.

At central government level, clear policy measures would stimulate the confidence required by industry to take action in the commercial sector, and overcome a number of market failures preventing the required investment in low-carbon construction. Local authorities also have a huge sphere of influence and a duty to promote the social, economic  and environmental wellbeing of their communities. As permanent bodies that plan for the long term, they are uniquely placed to play a significant part in achieving the national goal of developing a low-carbon economy.

With portfolios including many types of buildings that use significant amounts of energy, local authorities are responsible for town halls, civic offices, residential care homes, sheltered housing, homeless people housing units, museums, libraries, theatres, community centres, day centres, schools and sports facilities. Local government spending amounts to 25% of all public expenditure, and councils spend the largest proportion of this on education (41%) and social services (19%). Local government buildings offer a wide range of services, and therefore require different kinds of premises - buildings that are vastly different in size, structure and age, with some being older, refurbished properties while others are purpose-built. All of these features impact on energy use, and more importantly, on the opportunities for energy, carbon and cost savings.

The most common areas of excessive energy consumption, where savings can be made, include heating, cooling, lighting, ventilation and office equipment. Cost-effective measures involve reducing ambient room temperatures, improving building controls and monitors, replacing boilers and air conditioners with more efficient units, and installing additional insulation. More complicated interventions require major refurbishment of a building, and implementation of these measures is often limited to existing refurbishment cycles, as complex interventions are more cost effective when the building is being refurbished anyway.

When non-domestic buildings are refurbished, there are many measures that could be considered, including:

• Passive features, such as daylighting, shading and natural ventilation;
• Upgrades to the building fabric, for example replacing windows or adding insulation;
• Upgrades to equipment, including lighting, heating and cooling systems;
• The addition of on-site, low-carbon electricity generation, for example combined heat and power or biomass boilers.

A commitment to the low-carbon refurbishment of buildings also presents opportunities to improve comfort, satisfaction and productivity of occupants; demonstrates corporate responsibility; and brings a reduction in risks due to future energy cost and supply uncertainty. Moreover, it is possible for the public sector to make a significant contribution to the UK's efforts to develop a low-carbon economy in a cost-effective way.