Underfloor Heating Cardiff
Wet Underfloor Heating Specialists
Whether you’re planning underfloor heating as part of a renovation or you’ve got an existing system that’s stopped working, our heating engineers can handle it all.
Book an Engineer →Your Local Plumber in Cardiff
From bathroom retrofits to whole-house systems as part of an extension, our team handles wet underfloor heating systems from start to finish.
Gas Safe Registered (518700)
NJ Harkus is Gas Safe registered (518700), City & Guilds qualified and CIPHE members, with full public liability insurance for all plumbing, heating and gas work.
Highly Recommended & Reviewed
We’re trusted by homeowners, landlords and businesses across Cardiff for underfloor heating that’s installed properly, balanced correctly, and runs efficiently for years.
Underfloor Heating Installation & Repair
From New Builds To Existing System Repairs
Our team of plumbers handles wet underfloor heating systems from start to finish, whether that’s a brand-new installation as part of a renovation or a fault diagnosis on an existing system that’s stopped performing. Every job is carried out by qualified heating engineers and properly commissioned before we sign anything off.
Our underfloor heating services include:
- New wet underfloor heating installation
- Manifold installation and replacement
- Connection to existing boilers and heat pumps
- Zone valve, actuator and pump replacement
- Thermostat and controls installation
- Underfloor heating leak detection and repair
- Diagnosis of cold zones and uneven heating
- System rebalancing and pressure testing
- Repairs to failed mixing valves and motorised valves
- Commissioning and handover
Underfloor Heating Problem or New System?
Underfloor Heating Engineers Working Across Cardiff & The Vale
We install and repair underfloor heating across Cardiff and the surrounding areas, including Penarth, Sully, Barry, Cowbridge, Pontyclun, Llantrisant, and Dinas Powys. From single bathroom retrofits to full ground-floor installations in larger Vale properties, our team handles the work properly, whatever the project.
Business Hours
24 Hours, 7 Days A Week
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We Are Highly Recommended in Cardiff & The Surrounding Areas
New Underfloor Heating Installation
From Manifold To Final Commissioning
A well-installed underfloor heating system runs quietly in the background for decades. A badly installed one, however, shows up as cold spots, unbalanced rooms, and a thermostat that never quite seems to do what you want. The difference lies in the details at the installation stage.
We handle the full plumbing side of wet underfloor heating installations, from running and laying the pipework to fitting the manifold, connecting to your boiler or heat pump, and properly commissioning the system. We work with leading manufacturers’ systems and coordinate with builders for the screed and floor build-up where needed.
Most of our installation work happens during renovations, new builds, and extensions, where timing is critical, and we coordinate with the rest of the trades. The best time to bring us in is at the planning stage, so the system is sized correctly for your property and matched to whatever heat source it’s running from.
Planning a new underfloor heating system? Get in touch, and we’ll come and have a look.
Underfloor Heating Repairs
Cold Spots & Failed Components
Underfloor heating problems aren’t always where they appear. A cold spot in the kitchen might be a zone valve issue at the manifold, a stuck actuator, or a balancing problem that’s never been sorted out since installation.
Luckily, most repairs don’t involve lifting the floor at all.
We always diagnose the system before any invasive work starts. That usually means checking pressures, testing the manifold, looking at zone control, and identifying which loop or component is actually causing the issue. Where a leak is buried in the floor, we’ll narrow it down before any flooring comes up.
Common repairs include failed actuators, replacement pumps and mixing valves, faulty thermostats and controls, balancing issues, and pressure problems. Regardless of the fault, once the repair is complete, we’ll pressure-test the system, verify it’s running properly across all zones, and walk you through what we did.
Got underfloor heating that’s not working right? Get in touch, and we’ll come and have a look.
Frequently Asked Questions
Our Underfloor Heating FAQs
Will underfloor heating work with my existing boiler?
Most modern boilers will run underfloor heating without issue. The system runs at lower temperatures than radiators, which actually suits combi and system boilers well. We’ll check your existing setup as part of the quote and let you know whether your boiler needs to be upgraded to work properly.
My underfloor heating has cold spots. What's likely causing it?
Cold spots can come from a few different places. Most commonly, it’s a problem at the manifold, poor balancing in the system, or a faulty thermostat. Most are fixable without invasive work, and we’ll diagnose the cause before suggesting anything.
Can you find a leak in an underfloor heating system?
Yes, though it depends on where the leak is. Leaks at the manifold or in visible pipework are usually quick to find. Leaks buried in the floor screed need more careful diagnosis to narrow down before any flooring comes up. We’ll do everything possible to locate the leak with minimum disruption.
Can underfloor heating be installed without lifting the whole floor?
In renovations and new builds, the floor is already up, so installation is straightforward. In existing properties, low-profile retrofit systems can be installed on top of the existing floor without major disruption. We’ll come and look at the property and tell you honestly what’s involved before any decisions are made.
