Retrofit: Operational energy in the spotlight

The retrofit movement has gained momentum, but projects continue to face barriers.  

Cost is the one of the biggest barriers to reducing operational energy and carbon in retrofit projects. Money is expensive right now. But the industry recognises the importance of retrofit first and more stretching operational energy targets are on the horizon. 

A lot of built assets are sitting in prime locations that makes the economic case for refurbishment stronger. If project financing can be secured, how can operational energy be reduced?

Short-term gain, long-term pain

Project teams understandably have a focus on the practical completion alongside goals such as achieving a specific EUI target. But once practical completion has been reached and the tenant is in situ, operational energy consumption challenges arise that could have been overcome had they been considered at the design stage. 

As an industry we need to look beyond practical completion to the longer term, shifting the focus onto the whole life cost benefit analysis of equipment such as lighting or HVAC – and think if we spend a little more now what will the financial gain be once the building is in use? Most likely, a higher EPC rating and lower EUI – the opportunity to invest a little more today to bank future energy targets.  

If we are to accelerate change as an industry and hit Net Zero goals, we need to be more forward-thinking. The new UK Net Zero Carbon Buildings Standard will drive the momentum behind this. Pressure will also come from investors to align with their ESG objectives. So, it makes sense to get ahead from the off. 

Future-proofing assets to meet energy targets beyond practical completion will support income generation and asset value retention across the building’s life cycle. 

The bigger picture

So, what is the answer to getting retrofit projects right when it comes to operational energy? 

It’s critical to think holistically. To consider the end occupier – who will the building be leased to, what will their energy requirements be? This must be thought about at the refurbishment’s design stage – how the energy performance gap can be closed. Too often projects only consider how the building will be used when it’s handed over. By then it’s too late to factor in the capability to make significant reductions and to flex the building to suit tenants. 

Once the occupier is identified, you can plan for their energy needs in conjunction with what the asset has the capability to provide. All buildings are individual, so the retrofit strategy must be aligned with the asset in front of you. What can be worked with, what are the deal-breakers? 

You need to look at the cost of upgrading the energy infrastructure. What’s feasible within the project’s budget and does the grid have capacity? Consider the acoustics – will heat pumps on the roof upset the neighbours? And space – is there room for new plant? What is the trade-off with valuable amenity space?

Active and passive carbon reduction opportunities

To navigate these challenges, it helps to think about the refurbishment design from an active and passive standpoint. 

In refurbishment projects, highly efficient building services tend to be cheaper to install than upgrading the building fabric. Heat pumps and mechanical ventilation are a typical solution as they’re straightforward and cost effective. You can also invest in systems that understand the way the building and occupants work, supplying fresh air, heating and cooling only to the spaces that require them, which reduces operational costs and energy – but these will carry a higher upfront cost. 

However, if there’s a red line of grid capacity, acoustics or space it’s critical to consider the passive options. 

Passive is your building fabric. Generally, it’s easier to push further here with new builds, but that doesn’t mean progress can’t be made on retrofits. How can insulation levels and glazing be improved to bring down the building’s energy demand? Less plant will deliver better acoustics, more space for amenities and reduce operational energy and carbon. 

You need to choose an approach that works for the asset in question and tenant’s requirements. More insulation will reduce the net internal area, so how can you get around that? If maximising internal area is key, then the compromise will be on cost – sourcing manufacturers that can provide compact insulation that still delivers on energy efficiency. You will also need to remember that upping the insulation will increase the Whole Life Carbon and the risk of overheating. All of these issues need to be carefully considered and worked through. 

But if budget is the deciding factor, it may be the tenant can accommodate the trade off in floor area through hybrid working policies. And if the building becomes more sustainable in the longer term, there may be the potential to charge more per square foot so that the increased rental value delivers a better yield.

Final thoughts

Ultimately, we need to accelerate change and reduce EUI as targets will become more demanding over time. Retrofit projects offer the opportunity to transition and future-proof an asset. To succeed, it’s a case of understanding what you’re working with, and developing an operational carbon reduction strategy tailored to that asset and occupier. 

This article first appeared on the UK Green Building Council’s blog: you can read it in full here.