What is “The Performance Gap”?

NBT Updates

What do we mean by the “performance gap” when we talk about buildings?

When a building is designed, there is a targeted level of energy performance. Once a building is completed however, the reality is that these targets often aren’t achieved. The focus at the moment is on closing the gap between intended and actual energy performance, but it is becoming obvious to everyone that there is also an equal or greater gap in ventilation performance, comfort (particularly overheating) and general environmental performance.

More Than Energy

We are also concerned with the gap in fabric durability, usability and in what we term as “delight”, which covers issues such as daylighting, spacial layout and quality of finish. These are all important because buildings are more than just energy machines. They have a considerable impact on our well-being, culture and environment in many different ways.


Complex Buildings

In the building sector, there seems to be an acceptance of the performance gap as an inevitable consequence of the complexity of buildings. This is convenient to mainstream practice as it is a way of avoiding addressing these issues, and it means not having to change practice and process in the industry. But is this acceptable?

An Industry Problem

Most of the problems arise in the design and construction (or renovation) of buildings which can be addressed through better knowledge and more care. It does of course require legislation and realistic policy which focuses not on world beating technologies, or single focus targets, but on long term all round performance. Blaming governments however is no excuse for most of the performance gaps. The industry has to stop being in denial.


“Good” as Standard

Delivering buildings which are not healthy, comfortable or usable is not only irresponsible, but unprofessional. Good buildings should not be an added value offering, but the standard offering. The bar has to be reset. Those projects which fail to meet the performance which is required for a good building should not merely be seen as average, but as unacceptable. As failures.


In resetting the bar and widening the notion of performance, we can not only drive much needed changes in practice in this sector, but also raise the public status of building as well as industry self-respect. We can also start to reduce the importance and viability of those players who don’t care and whose only concern is the gap in their profits. It is time to get real.