Our services

Callens has the answer to all your thermal needs! We don't only design and install your system, but take care of its commissioning too. We also provide a 24/7 call-out service to prevent any production downtime.

Full integration

We execute every contract in-house, primarily with our own staff. Our vertically integrated approach allows us to follow up each project from start to finish. Engineering, installation, service and follow-up. Callens does it all!

Our horizontal integration makes us a multi-disciplinary partner for our customers. Our expertise in steam boilers and thermal oil boilers, energy recovery, industrial piping and air technology means that we can offer you a total cooling and heating solution.

thermische installatie Callens

In-house engineering department

Our concept and sales engineers, project managers and leaders and draughtsmen never fail to come up with a solution to any heating need or problem. Our teams work out your project in minute detail before issuing you with a competitive quotation for the final concept.

Our technology engineers keep a close eye on the technical standards and a keen eye on any innovations our R&D department comes up with. And as you might have guessed, we are regularly asked to work out one-off concepts by and/or in association with renowned engineering firms.

Eigen studiedienst Callens

24/7 service

To prevent any downtimes in your production, our customer service can be contacted round the clock, seven days a week. As our service team, backed up by the necessary specialists, is on standby day and night you can rest assured that we will be with you within 2 hours.

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24/7 service Callens


Our 200 enthusiastic, highly trained 'Cauls' prides itself on its outstanding customer service: engineers, qualified welders, fitters, burner technicians, project leaders, draughtsmen, prevention advisors, thermal specialists, service and automation engineers,

all of them with your interests at heart!

Medewerkers Callens thermische installaties

Spare part and rental boiler stock

We have more than 24,000 different spare parts and some 25 rental boilers in stock. An additional guarantee for a sure, reliable production.

Voorraad wisselstukken Callens


As nothing makes us happier than a happy customer we settle for nothing less than perfection, whatever the project. This is also the reason why we have been working with the same partners, who operate to the same high standards, for years.