Sustainable Retrofit lessons, from a Property Owners perspective

11 April 2024
Grosvenor Building

Sustainable Retrofit lessons, from a Property Owners perspective

11 April 2024

At Grosvenor, we have just retrofitted over one million square feet of our London portfolio, part of a wider £90 million commitment to making our historic estate more energy efficient.  

Our London holdings range from large commercial premises to Georgian townhouses of Eaton Square to two-up two-down mews houses. Just over 50% of them are listed and around 95% are in a conservation area. While our estate is largely historic, the lessons we have learned carry into the refurbishment of more modern buildings as well.

Our retrofit programme 

In 2020, we began a £90 million programme to increase the energy efficiency of our London estate. We already had experience in this area, as we’ve been carrying out sustainability focused building retrofits since 2008. However, this programme represented an escalation in activity to meet our goal of reducing emissions across all our activities by 90% by 2040. 

With 27% of our 2019 baseline emissions coming from our standing portfolio, retrofitting our properties is a central component of how we will achieve this reduction. 

Our milestone is a significant achievement, mobilising many teams and partners. Here’s a snapshot of what we’ve learnt along the way. 

1. Involve your tenants 

With a near fully-let portfolio, a lot of our retrofit works have been conducted with tenants in situ. Good communication and planning go a long way to making the works run smoothly and allowing us to navigate sometimes unpredictable schedule changes.  

It has also paved the way for future conversations about improving how the building is operated to maximise the impact of the retrofit.  

2. Build your internal team and skills 

Partnership working internally is as important as it is with external stakeholders. At Grosvenor, sustainable retrofit has pulled in many teams and skills – we’ve been able to learn from each other and by reducing silos, we’ve been able to better plan to minimise inadvertent delays and costs. 

3. Leverage the learning available 

There is far more information out there now than when we started in 2020. You can find a retrofitting handbook on the website of City of Westminster Council. Also, look at guidance and events from the UK Green Building Council and of course, the Better Buildings Partnership, including the BBP’s Low Carbon Retrofit Toolkit.

4. You don’t have to wait for an empty building 

Deep retrofit is more effective and long lasting than a light retrofit. That said, waiting for vacant possession isn’t always feasible practically and financially. Simple cost-effective changes can significantly reduce energy demand and improve a building’s sustainability. Acting now to make straightforward low-cost changes is a more effective approach than postponing activity until a full building refurbishment may be possible; small changes can add up over time to deliver big savings. 

5. Invest in the tech 

We’ve had significant success in reducing building emissions and running costs through better data – we have a relatively granular portfolio, and these investments work as effectively for us as they do for larger buildings. Installing monitoring systems are  also less intrusive than physical works and provides the ability to remotely manage plant and machinery. We’re also looking now at predictive maintenance to enhance occupier experiences, reduce emissions and running costs. 

We often use our head office to pilot new technologies to support us in our drive for net zero carbon. 70 Grosvenor Street was our first commercial property to be retrofitted with: air source heat pumps, AI driven AHU controls, and remote monitoring technology, air quality monitoring, occupancy sensors and intelligent lighting controls. This provides us with a direct understanding of a technology before we roll innovations out to our customers. 

6. Build your supply chain early 

Building your supply chain is a key element of planning – you need someone to execute your programme. For us and many others, historic buildings also require specific skills to ensure that the building is protected for the long term.  

In addition, maintaining the skills to continuously improve the retrofit of your properties requires a constant awareness of the new technologies coming through in the market and the skills you will need to utilise them. Your supply chain is critical for this. 

7. Understand your local authority’s perspective 

Particularly when it comes to the heritage environment, there remains friction between protecting the historic character of a building and protecting its future. Understanding the approach of your relevant planning team to the climate emergency, heritage protection and retrofit works will avoid programme delays and costs.


We still have a long way to go to meet our carbon goal and will continue to learn as we go. If you would like to discuss our experience in retrofit or have innovations to share, please contact me at