Sustainable Retrofit

Refurbishment has arguably the greatest role of all to play in creating a more sustainable future, despite the more onerous constraints or working with existing fabric and services. Retrofit is the term used to describe the upgrade of buildings with measures to improve their energy performance or health and well-being. These might include interventions such as additional of internal or external insulation, replacement fenestration, improved air tightness and ventilation or heating and hot water system upgrades.

With the oldest stock of buildings in Europe it is vital that retrofit becomes more common place if the UK is to make meaningful reductions in its environmental impact. Additionally, our low rates of demolition and replacement require us to retrofit some 26 million homes and non-domestic buildings over the coming decades!

The potential for improvements will vary according to building typology but, whatever the level of refurbishment being considered, it is important that a whole building retrofit strategy is followed. The most cost-effective aim is to ‘do it once and do it well’ – ie make deep cuts in energy use now or at least not create barriers to future upgrades through half measures – hence the emerging term ‘deep’ retrofit.


Whole building retrofit can be a complicated operation requiring multiple processes and trades to come together in a coherent fashion. This complexity means that there are many areas where retrofit might fail to reach the desired outcomes, either as a result of inadequate analysis, inappropriate design decisions, supply-chain obstacles, poor quality installation practices on site or ineffective occupier engagement and handover regimes.

Cowan Architects bring expertise and efficiencies to the planning, delivery and handover of a project, potentially reducing the costs associated with delays or re-working and providing an open and integrated approach to communication across the design team, contractor, site team, occupants, neighbours and the client organisation. The attention to detail that we offer will be of enormous value in ensuring the necessary technical performance of measures such as continuity of insulation, improvement in air tightness, control of moisture or incorporation of renewables.

For social landlords or local authorities, retrofit can have wider-ranging benefits above and beyond simply saving energy and reducing emissions. We have experience in projects where tenanted properties have been transformed through retrofit measures including on-site renewable energy generation. With post-war stock in particular, improvements can be dramatic – up to 80% reduction in energy costs, for example. The benefits to tenants in terms of having comfortable warm homes with affordable bills are tangible – improved health and mental well-being, greater security and less likelihood of getting into rent arrears. For landlords, comprehensive retrofit can extend the life of their housing assets for another 30-40 years and reduce the burden of complaints, repairs and maintenance. The key to a successful social housing retrofit is resident engagement and we can offer great experience in working with residents from the very beginning to gain support and ‘buy-in’ to any retrofit scheme – this is especially important where there may be leaseholders who quite understandably have a different set of concerns to tenants.


For many businesses and commercial enterprises, the recruitment and retention of high-quality staff is the greatest investment they will make. For staff choosing a choosing a career move, on the other hand, decisions may be increasingly influenced as much by the quality of the workplace and the employer’s commitment to the green agenda as it is about pay and benefits.

Retrofit can therefore add enormous value to existing buildings through the creation of better quality working environments and through the demonstration of environmentally-conscious corporate responsibility, not to mention the reduction in overheads and staff sickness. Time and time again, retrofit shows itself to be the more cost-effective and less disruptive option over demolition and rebuild.

Likewise, for other institutions such as schools and universities, these issues are high on the agenda and the retrofit of existing buildings can be transformational. For charities and community organisations alike, reducing running costs can make the difference between hand-to-mouth survival and continued economic sustainability.

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