What is retrofitting 

Reports show that 80% of buildings that exist today will still exist, and still be functional, by 2050. Put simply, ‘retrofitting’ is the process of improving an existing building by adding or upgrading features and/or replacing materials or technology so that the building is more energy efficient. It can cover anything from insulation and glazing to heating controls, ventilation, LED lighting, heats pumps or solar panels. 
 
The commercial and environmental benefits 

The commercial benefit of retrofitting is clear: more efficient buildings translate to lower energy costs, where funds can be reinvested elsewhere. A study from consultants Christie & Co found that care homes improving their Energy Performance Certificate (EPC) ratings from D to C increased annual profitability by an average of £320 per bedroom. For organisations that own buildings as part of their operations, retrofitting and upgrading today will lead to substantial savings compounded into the future. 
 
Challenges organisations face with retrofitting 

Despite the commercial benefits, large retrofit projects are not straightforward. Findings from the roundtable highlighted misaligned priorities between landlords and tenants. Landlords are typically responsibly for the higher-cost retrofitting projects (such as installing solar panels), while it is the tenants who benefit from the reduced energy bills. This can lead to a lack of incentive for landlords to invest in retrofits for their buildings, “weakening the business case where costs and benefits fall to different stakeholders”. 
 
The cost for retrofitting buildings is significant, often requiring a large upfront investment with organisations seeing a large payback period (the time taken to ‘pay back’ the upfront costs through its savings). The report has also found that regulation for retrofit projects is evolving slowly, with policymakers requiring “repetitive and extensive evidence”, which inevitably delays action. 
 
The help available to organisations  

In some instances, financial support is available from the UK government. For instance, in 2026, the West of England Combined Authority offered Green Care Home Grants to support measures such as insulation, glazing, heating improvements, ventilation, LED lighting and solar PV. Elsewhere, Soham Lodge Care Centre secured just under £100,000 in matched funding through the Cambridgeshire and Peterborough Combined Authority. The resulting work included triple glazing, solar panels, rainwater harvesting and air conditioning, and the Combined Authority reported annual energy cost savings of around £30,000. Funding varies by location and scheme, so it is worth checking with local authorities, growth hubs and sector bodies before ruling projects out on cost alone. 
 
How ESOS can support your retrofit projects 

Before considering a retrofit project, it is valuable for organisations to understand how energy efficient their buildings are through the Energy Savings Opportunity Scheme (ESOS). This involves an official audit carried out by an ESOS consultant every four years, with the next requirement being ESOS Phase 4.  
ESOS is mandatory for some organisations. An organisation will qualify for Phase 4 if, on 31 December 2026, it meets the definition of a large undertaking. This includes organisations with 250 or more employees, or those with annual turnover above £44 million and an annual balance sheet total above £38 million. The Phase 4 compliance deadline is 5 December 2027. By preparing early, organisations unlock significant commercial benefits: the audit can reveal where energy is being lost across an estate and where investment is likely to have the biggest impact. That insight can then feed directly into a retrofit plan. 
 
Planet Mark is a leading net zero certification based in London, helping over 700 members measure and reduce their carbon emissions since 2013. Get in touch today to learn more about ESOS Phase 4 and embarking on a commercial retrofit project, here: Talk To Our Experts - Planet Mark | Sustainability Certification.