Reducing carbon emissions in existing housing

In the UK we have the oldest stock of housing in the developed world, yet emissions from this source will have to be virtually eliminated by 2050 to meet climate change targets. About 80% of these dwellings will still be around by that date, which crudely translates to 11,000 whole-house refurbishments a week for the next 40 years.

This needs an industry-wide approach, across a broad coalition of professionals: policy-makers and finance experts to set up a viable framework; surveyors capable of carrying out advanced energy audits; multi-skilled retrofit contractors familiar with low carbon measures and technologies. And at the centre of this delivery chain should sit the consultant architects and engineers.

The design community can and should make a crucial contribution to what UK-GBC chief executive Paul King described in these pages as a “revolution” in the way we refurbish buildings. Sure, filling cavities and loft spaces with insulation doesn’t require their particular skills, but reducing emissions from our existing homes by 80% often means interventions that go far beyond those simple measures.

My practice’s recent “retrofit and replicate” pilot for Hyde Housing Association employed super-insulation internally and externally, Passivhaus-standard window replacements, air leakage reduction, boiler renewal, retrofitted MVHR, 100% LED lighting, solar thermal collection and 10m2 of photovoltaics. Such a range of interventions requires careful co-ordination and design consideration.

Insulation of solid-walled properties, arguably the next “low-hanging fruit”, is going to have significant implications for the appearance and architectural integrity of our homes, either through internal dry-lining or external cladding with render or rainscreen systems. The attention to detail that an architect offers will be of enormous value in accomplishing the necessary continuity of insulation, improvement in air tightness, control of moisture or incorporation of renewables in a low carbon retrofit, not least by communicating clear solutions to the workforce.

Reducing emissions from the UK’s existing housing stock by 80% will require interventions that go far beyond filling cavities and loft spaces with insulation

The vast swathes of post-war estates and tower blocks owned by local authorities and social landlords are obvious candidates for this approach. In many cases, CO2 reduction could be seen as a welcome motivation to transform the appearance of the property. Conversely, with 1.2 million homes lying within conservation areas, we need to preserve our built heritage while giving all households a fair opportunity to reduce their energy needs and costs.

The 70% of UK dwellings that are privately owned are a much larger and more fragmented challenge. In time, this will have to be tackled on a street or neighbourhood scale to achieve the retrofit rates necessary. In the meantime, green-minded homeowners will be looking for independent advice on the best approach to eco-retrofit. The staple diet of many a small practice or sole practioner – extensions, loft conversions and the like – will be a trigger point for energy improvements to the rest of the property. To this end, the RIBA’s Climate Change toolkits are intended to disseminate the principles of low carbon design throughout the profession.

The coming weeks will see two events where designers can display a clear commitment. Grand Designs Live, 25 April to 4 May, will see the launch of the Great British Refurb campaign, providing a platform to engage with the public. And the government’s Heat and Energy Saving Strategy consultation, which closes on 8 May, is an opportunity for the design community to demonstrate its potential contribution to the retrofit challenge. The Existing Homes Alliance estimates that even a 60% reduction in dwelling CO2 emissions would result in 15 times more savings than will be achieved through demolition and new-build by 2050. So how can the design professions’ commitment to a sustainable future be taken seriously by the construction industry, and indeed the public, if we choose not to engage with this radical programme of transformation?

While we vacillate over the exact definition of zero carbon for new-build projects, we are in danger of overlooking a much greater contribution to UK emission reductions.