Energy-efficient office buildings, what’s the future?

expert interview with Geert De Bruyn and kreon

Geert De bruyn is an energy-efficiency and sustainable building expert and also the head of the research agency GDb engineering. Clients, architects and complete building teams count on GDb engineering to advise, guide and support them to be as energy-efficient as possible. With his renowned and established expertise in sustainable building, we asked Geert De bruyn what the future holds for energy-efficient construction professionals.

What is your role within the building process?

Geert De bruyn: “ When a new building is designed, we can be included from the concept phase to achieve a sustainable energy active building within budget. We not only design the energy concept of the building, but also the engineering of all the different techniques, the EPBD reports and the aftercare during the first years of use.”

You talk about an energy active building. Could you please explain this further?

Geert De bruyn: “First of all you have a NZEB, which is a Nearly Zero Energy Building. That is the legal requirement for all new buildings in 2021. The absolute minimum. Subsequently, you have energy neutral, which only refers to the building. This results in an energy level of 0. But we prefer to go one step further. Buildings that we design are not only energy self-sufficient, but they even create the energy that the owner needs for all their electrical appliances and cars. That’s what you call an active building.”

“We prefer to go one step further than a zero energy building and strive to create an active building, to provide the energy that the owners need for their electrical appliances and cars.”

How does one start creating an active building?

Geert De bruyn: “There are no ready-made answers. Every client has their own specific requests and every building has its own energy demand. Our first step is to work out what these demands are. We start with creating a concept with the best available techniques to have an energy consumption that is as low as possible. Again, this is not a one-size-fits-all solution, but always custom designed. For every project, we design a combination of the most suitable technologies.”

These type of decisions are certainly made in function of different factors. Which factors have the biggest influence?

Geert De bruyn: “Most often it’s the budget. Of course, we don’t just get a blank cheque, but we work pragmatically and take realistic building budgets into account. Naturally, choices need to be made. The sooner you have your energy plan worked out when you’re building or renovating, the lower the additional costs will be.”

“We work pragmatically with realistic building budgets. The sooner you have your energy plan worked out, the lower the additional costs will be.”

Who is generally the person that decides to add an energy efficient advisor to the building team?

Geert De bruyn: “Most of the time it’s the client, as they are interested in the lowest Total Cost of Ownership. They want to make sustainable choices that will result in financial benefits in time. Entrepeneurs typically decide on ecological and sustainable options from an economic point of view. There are also architects, promotors and contractors as well that take the initiative. They do this because of a successful collaboration in the past and they feel that the client would be interested in this.”

“ Most of the time, it is the client that decides to also pay attention to the energy levels of their new building project. They are interested in the lowest Total Cost of Ownership and want to make sustainable choices that will result in financial benefits.

Have you noticed a change in the mindset of the building industry throughout the years?

Geert De bruyn: “I have been an energy and sustainable building advisor for 25 years and I see a big difference. Once I had to advise to use double glazed windows instead of single…for a new build! Thanks to the revision of the EPBD norms in 2006 big changes were made regarding energy performance as well as the building envelope and building techniques.”

What are your expectations for the future?

Geert De bruyn: “To design an energy active building you must be aware that there is also energy left to cover all the facilities. This is calculated based on the needs of the user, their activities and even means of transport. Mobility is in full development, that’s why I expect many changes within the 5 years from now on.  We have to stop using fossil fuels and choose for heat pumps and geothermal energy. Building-integrated solar energy systems in combination with a battery system will become a must-have. I’m optimistic about the future but I don’t think we will become obsolete anytime soon.”

“I expect many changes within 5 years from now when it comes to transport and the impact it has on how we design buildings.”

“I’m optimistic about the future but I don’t think we will become obsolete anytime soon.”



The people at kreon keep evolving, constantly focussing on the latest construction innovations. “kreon supports their clients with advice, products and continuous developments.” explain Nick Janssens and Johan Van Acker: two experts at kreon who are responsible for vektron ceiling solutions, a department within kreon that specialises in metal ceiling systems with integrated technologies.

“We recognise what Geert De bruyn states: the sooner you bring the right parties around the table, the most beneficial it will be. At kreon we carry out our primary role within the building process together with the other involved parties. From the initial meeting with the (Interior) architect to the design office. And from concept stage to the execution and the follow-up with the main contractor. Our domain is the ceiling which is the horizontal carrier of diverse technologies and comfort solutions. We ensure that it fits seamlessly within the total building concept”, explain Nick Janssens and Johan Van Acker.

“The sooner you bring the involved parties around the table, the most profitable it will be. At kreon we carry out our central role within the building process.”

“It is true that there is no such thing as one-solution-fits-all when it comes to the design of a building, on the contrary, every building is bespoke. kreon therefore considers the techniques as the starting point. We shape the ceiling around the specific technical requirements and bring different elements together, bearing the aesthetic wishes of the client in mind. The result? A unique ceiling solution tailored to each project. And of course, we consider the budget to be the determining factor as kreon offers a range of flexible integrated solutions: sound absorption, light, climate, ventilation, audio, … This is how we ensure a solution for every budget.


“The solutions are the starting point. The ceiling is customised around the specific technical requirements, bearing IN MIND both the aesthetic wishes of the client and their budget.”

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