We’ve been taking care of things for over 200 years. And we’ve learnt a lot in that time. That’s why over 10 million customers trust us in their homes every day – whether it’s fixing their boiler, installing a heat pump or simply powering their kettle.

But you don’t get there without the right people. And we’ve got thousands of them all over UK – including 6,500 highly skilled engineers and technicians. Every single one of them represents the diverse communities we serve. And they’re on a mission to make life easier, greener and more affordable every day.

We are Calisen. We own, install and manage essential energy infrastructure assets across both domestic and commercial properties. We’re building a more sustainable, smarter world for the next generation.

Horizon Water Infrastructure specialises in water resource management, delivering end-to-end metering and data solutions for water companies. Backed by KKR and part of a group of industry-leading companies, including Horizon Energy Infrastructure and Smart Metering Systems (SMS), we bring over 30 years’ experience in large-scale rollouts. Our smart infrastructure expertise and innovative financing models spread programme costs over 10 to 20 years. Through our Metering-as-a-Service (MaaS) model, we mitigate risks, enabling utilities to focus on service while meeting UK Government and Ofwat mandates. Recently appointed to replace over one million meters for Southern Water, HWI is setting a new benchmark for efficiency, sustainability and impact.