Building Energy Efficiency

The built environment contributes around 40% of the UK’s total carbon footprint. Almost half of this is from energy usage. So building energy efficient buildings is a key way in which we can contribute to reducing the UK’s carbon emissions. It can also save our customers money on their energy bills.

We have significant expertise in designing and delivering plans to achieve reductions in energy and carbon emissions to meet BREEAM or ‘London Plan’ energy and carbon reduction objectives. This means that we ensure that the carbon reduction targets on paper at design stage are realised when the building is operational – and with realistic and affordable operating costs.

Design stage/theoretical

Energy efficiency starts at design stage. This means that the building design needs to include:

  1. Well insulated and airtight walls, floor and roof
  2. Building services (lighting, for example) which are energy efficient
  3. The potential for fitting renewable technologies which can generate power (for example, solar panels)

These three points help to define a building’s theoretical energy performance, as set out in its EPC. However, the gap between theory and actual practice can vary greatly.

In use stage/actual

A DEC (Display Energy Certificate) is a much better indication of a building’s performance than an EPC, since it expresses its energy usage while occupied. In our five-step strategy to achieve the required DEC rating, we

  1. develop total energy/carbon targets for the project
  2. track these energy targets through detailed design and procurement,
  3. put in place commissioning and handover processes that ensure the occupiers understand how to get the best energy performance from the building
  4. provide support to establish energy monitoring and evaluation
  5. undertake a review performance over the first two years and find ways of driving down usage further.

Post-occupancy evaluations and building performance improvement, including Soft Landings

By studying in depth how some of our key projects perform in use, from handover, until up to 2-3 years on, we can answer not just the question ‘What energy performance level is my building achieving ?’ but the more important issues of:

  • Why is the energy performance of my building like this ?
  • How can I improve the energy performance of my building ?

Willmott Dixon’s in-house sustainability team, Re-Thinking, has extensive experience in carrying out POE studies on a wide range of buildings. This is typically carried out as an element of the Soft Landings stage 5 extended aftercare process and involves:

  • In-depth energy performance monitoring to understand not just what the performance the building is achieving, but why energy performance issues may be occurring, and how performance can be optimised and improved.
  • Interviews and surveys with staff, FM team and users to establish key areas of performance success and areas to improve in terms of building environment, maintenance issues, design and functionality.
  • Examining key building outcomes in terms of the customer’s project brief objectives e.g. building utilisation, workplace productivity, financial returns etc.

Lessons learned from this important research are fed back into the business, to improve the performance of future projects.

Introducing Energy Synergy

In 2017 we brought together a team of M&E and sustainability specialists from across our business to conduct long-term studies on 21 non-domestic buildings, with a combined value of nearly £400m, following them from inception to completion.

The team is carrying out post-occupancy evaluations on groups of projects, comparing energy results with other similar buildings, and against UK benchmarks.

They have found many reasons behind the performance gap - including unrealistic modelling, poor design and systems management – and are working to tackle these issues.

The approach has already helped our customers make energy/operating cost-savings of 5-15%, is improving occupier comfort and informing future builds.

The UK’s leading Passivhaus contractor
Willmott Dixon is a founder member of the UK’s Passivhaus Trust.

Developed in Germany in the early 1990s, Passivhaus is the one of the fastest-growing energy performance standard in the world.

A Passivhaus building is so well insulated that it does not need a conventional heating or cooling system. This means that energy usage (and energy bills) is significantly lower than in a non-Passivhaus equivalent building.

Our most recent Passivhaus projects:

George Davies Centre

Sutton School