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35 years of expertise meets German-engineered precision: A look inside the Warm NZ x Rehau story

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11 January 2026

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4 min read

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Arriving in Sydney from across the Tasman, Sean Stephens wasn’t sure what to expect. But stepping into the Rehau Academy for hydronic heating training in 1998 was about to change how he looked at heating and, ultimately, how New Zealand would experience heating.
Sean Stephens, Director of Warm NZ and Plumbcraft.
Sean Stephens, Director of Warm NZ and Plumbcraft.

“We’d never really seen plastic pipes of this quality before,” he recalls. “That’s what struck us first, the higher quality of what we were used to.” 

But it wasn’t just the material, it was the hum of energy and knowledge around him. The trainers guiding them through weren’t salespeople or reps who didn’t truly understand the technology. They were engineers who had come straight from the factory floors in Germany, the same engineers who had spent years shaping, refining and testing the very pipes that Sean stood in front of now.

It was a turning point, setting the foundation for what would come: bringing German-engineered heating precision to New Zealand homes and commercial projects for the next three decades.

Plumbcraft has been installing central heating for 35 years and has had a strong relationship with Rehau since they came to New Zealand in 1998. "We set up Warm NZ in 2012 to separate the design of systems and the supply of products from our installation through Plumbcraft," says Sean.

Bringing new knowledge to New Zealand and eliminating the guesswork

Where Rehau stood out was in their detail. Their engineered schematic drawings were unlike anything Sean had seen locally. “Anyone can draw a layout,” he says. “But that doesn’t mean it’s engineered.”

Every pipe, connection and circuit was backed by calculations, modelling and expertise. In the early years, correspondence and drawings were sent by email, and sometimes even mailed back and forth between the two sides of the world. Today, collaboration is through an online portal that simplifies every step. 

Over the years, Sean’s seen plenty of local plans that could have led to costly failure. “Drawings that would’ve failed and cost millions.” Instead, the plans by Warm NZ and Rehau are grounded in certainty. There’s a rhythm: Sean sits down with clients early, reviewing plans, refining layouts and ensuring every detail is engineered, not guessed. 

“The portal prompts us for every detail,” Sean explains. “You can’t miss anything, and they can’t guess anything. It’s always a design done by the engineers, by the manufacturer.” There’s no uncertainty, just confidence.

The underfloor systems are all custom-designed by qualified heating engineers. Instead of using radiators to heat a room, hot water pipes are laid either into the concrete floor slab or under wooden floors between the joists. This warms the slab/floor, providing a warm floor and radiant heat in the room.

Comfort hidden in plain sight

A gentle warmth underfoot, so discrete you don’t even notice it. That’s the magic of hydronic heating. “With a really good system, you don’t even know it’s there, you’re just comfortable. You’re not too hot, you’re not too cold, you don’t notice it.”

Hidden, buried permanently beneath a building, this is where getting it right the first time matters. “There are no sharp edges, nothing is visible,” says Sean. “With underfloor heating, it’s there long-term, buried in the concrete for the life of the building. So, you want the best pipe.”

This confidence comes from years of experience. Across millions of metres installed, they’ve only seen one defective pipe. “Just a pin hole.” Even repairs are fully covered under Rehau’s warranty, due to the Rehau EVERLOC jointing system, something otherwise uncommon here in New Zealand. “There’s often the excuse not to carry warranties if there’s a repair under the concrete.”

With a really good system, you don’t even know it’s there, you’re just comfortable. You’re not too hot, you’re not too cold, you don’t notice it.

While Sean eagerly awaits his next trip to Frankfurt, where his team visits every two years to spend time with Rehau, finesse their skills and learn what’s next, he’s looking ahead to all the projects rolling out the new Rauvipex Pre-Insulated Pipe Heating System. When he learned about this on the last trip, it felt like a natural evolution and reminded him of the first time he experienced Rehau’s work. 

“Hand on heart, I have absolutely zero worry about any design or product that’s been made by the Rehau engineers.”