New buildings are the main focus of the government’s campaign to reduce emissions from the built environment yet the existing stock remains largely untouched

This will have to change if the UK is to meet its commitment to reduce carbon emissions by at least 80% by 2050, particularly as more than half of the buildings that will be standing then are standing now.

The situation is unlikely to be helped by the government’s U-turn on the inclusion of consequential improvements to existing buildings in Part L 2010. This would have forced homeowners planning an extension to spend a sum equal to 10% of its cost on improving energy efficiency in the existing house. Just as it did in 2006, the government has thrown away an opportunity to tackle emissions from our old stock.

This emphasis on new building is naive: once cost and embodied energy are taken into account, refurbishment can be a far more environmentally friendly and sustainable option. It is, of course, easier to achieve energy efficiency in a new building than with the carcass of an existing one. But Ashburton Court, the subject of this month’s Building Analysis, shows how much can be achieved.

On paper, the grim and inefficient 1960s headquarters of Hampshire County Council was ripe for demolition. An enlightened client, a visionary architect and an enthusiastic engineer produced a refurbishment both cost-effective and sustainable. Not all projects will have the same scope for energy saving as this large-scale revamp, but even partial refurbs offer opportunities to reduce emissions.

One note of caution: the Carbon Trust says that many refurbished offices end up generating higher emissions than the original because their remodelled interiors are able to house more occupants, which results in greater unregulated energy use for things such as catering. Perhaps this is an argument for not doing too good a job on the refurbishment – or making sure the tenants employ a bad chef.