From grocery mentality to circular vision: why Roger Keijsers no longer wants to throw away working installations

In a Limburg grocery family where nothing was wasted, Roger Keijsers learned early on the value of things. As Business Development Director at Interduct Group, he translates that upbringing into a message for the construction and installation industry: stop throwing away, start reusing. Bright spoke with him.

Vegetables that looked less than attractive were simply made into a meal. An orange with a blemish was not thrown away, but carefully utilized. That mentality, frugal, practical and respectful of what is already there, is the basis of his vision of sustainability today.

A philosophy that wins awards

During trade fair VSK+E 2026, Keijsers stood out by presenting not a product, but a body of thought. And with success: he won both the professional jury award and the public award. A unique achievement in the history of the event. His message is as simple as it is confrontational: the industry must get rid of the disposable mentality. "We already have everything," he states. "Why are we taking working plants off the wall to replace them with new ones?"

At a time when raw materials are becoming scarcer and more expensive, Keijsers finds it incomprehensible that usable materials are discarded en masse. His vision: utilize what is already there, and see existing systems not as waste, but as valuable raw materials.

Growing up with 'not wasting anything'

The origins of that vision lie in his youth. Keijsers grew up as the youngest in a family with a grocery store. There was one clear rule: nothing was thrown away if it was still usable. Products that were no longer marketable were given a second life in the kitchen. "You learned naturally to look: is it really bad, or does it just look less pretty?"

That practical outlook now forms the core of his professional conviction. Where others see waste, he sees potential.

From landfill to raw material

That conviction took concrete form when 11 of the 23 Interduct companies had to relocate in a short period of time. The operation produced a huge mountain of waste. Instead of disposing of everything, Keijsers decided to take a different approach: carefully disassemble and separate.

As it turned out, a large proportion of the "waste products" were still functioning fine. They were simply dirty or cosmetically damaged. Sometimes removed units were even still under warranty. That insight led to an important turning point: why shouldn't these products be reused? The idea of circular installation took tangible form here.

Looking at sustainability differently

According to Keijsers, the biggest challenge is not in technology, but in mindset. The sector now focuses heavily on insulation and energy saving, but often forgets about the indoor climate. "A well-insulated house without ventilation is unhealthy," he argues. "We must first ensure a healthy indoor climate and only then optimize and insulate." That call for "thinking around" goes beyond technology. It requires a different order of thinking and acting.

Music, emotion and impact

Remarkably, music plays an important role in Keijsers' life and vision. Together with his father, who was a member of the brass band for more than seventy years, he performed throughout Europe. But the most impact was made by a small performance in a care facility. For residents who could barely move, he and his father played music. What followed was an unexpected response: movement, emotion and connection. "That was real experience," he says. "Not the big stages, but those small moments made the difference."

It's a lesson he brings to his work: real impact is not in scale, but in meaning.

Perseverance after setbacks

His story took on an added dimension when he was struck by a brain infarct. From an active working life to complete dependence: it forced him to start all over again. Step by step, he worked toward recovery. Small progress became his new benchmark. At the same time, his vision remained intact and even grew.

When he returned, he found that his client BAM had carefully continued his thinking. "That's the best thing about it," he says. "That the idea remains, even if you're not around for a while."

A sector in motion

Today Keijsers is working with parties such as BAM on concrete applications of his vision. Installations from one neighborhood are remanufactured and newly installed in another. What used to be waste is being reused. It shows that his philosophy is not only inspiring, but also feasible.

The legacy of a 'ventilation man'

What does Keijsers hope people will say about him later? Not necessarily that he won awards or led projects, but that he made people think. "That they say: he had a story, he had passion and he was a nice guy too."

Perhaps that is the core of his success: a combination of a down-to-earth Limburg upbringing, personal resilience and an infectious belief that things really can be done differently.

Roger was previously a guest at Bureau Stoer. Listen here to the episode in which he talks enthusiastically about his refurbished second-hand ventilation boxes.