Underfloor heating on the ground floor is something most homeowners are familiar with. Warm tiles underfoot in the kitchen, a cosy bathroom that never feels like a shock on a cold morning. But what about upstairs? It’s a question we get asked regularly at Cozia, and the answer is: yes, absolutely, with the right system and the right advice.
That said, UFH on upper floors has a different set of considerations than ground floor installations. Let’s explore some important things to think about before you decide whether it’s right for your home, your budget, and your flooring plans.
It Doesn’t Have to Be All or Nothing
One of the most common misconceptions about underfloor heating is that it’s a whole-house commitment. It isn’t. Many homeowners choose UFH on the ground floor – perhaps in an open-plan kitchen-diner or throughout the downstairs – while keeping traditional radiators upstairs. This is a perfectly sensible approach, and one we help plan and install regularly.
Radiators remain a popular and practical choice for upper floors, particularly where bedrooms are carpeted. Carpet acts as an insulating layer and while UFH can work with carpet (provided the combined tog value of carpet and underlay doesn’t exceed 2 at the maximum), the efficiency benefits are reduced compared to hard floor finishes like tile, stone, or engineered timber. If your upstairs rooms are fully carpeted with a thicker pile carpet, and you’re happy with your current radiators, there’s no reason to change them.
Where UFH really comes into its own upstairs is in rooms with hard floor finishes — an ensuite bathroom, a landing with engineered oak, or a loft conversion with tiled floors. These are often the spaces where the comfort and luxury factor of UFH makes the most sense.
System Options for Upper Floors
Upper floors present different structural challenges to ground floor installations, and the system choice reflects that. Here’s a rundown of the main options:
Joist Deck Systems
These pre-routed chipboard panels are the most widely used solution for timber suspended floors, which is exactly what most first and second floors are. The panels sit directly over the joists, meaning there is minimal floor height increase. Though this system is a more costly solution, if floorboards are being replaced, the cost is offset against new 22mm chipboard panels.
Screed Systems
Where structural loading permits, which is more common in new build scenarios rather than renovations of older properties, screed systems can be installed on upper floors. Block and beam floors and builds using Lewis Deck on Posi joists can take deeper screed pours. Mini screed systems comprising a low-profile castellated ‘FLO’ tray with 12mm pipe and 25mm screed depth also deliver excellent heat output and long-term efficiency, with less load. Cozia’s team will always ensure clients have taken structural suitability into account as part of the design process.
Low-Profile Overlay Panels (e.g. RetroTherm® LITE or Backer Board)
Where you want UFH to be installed over an existing floor surface, low-profile overlay systems offer a practical alternative. Systems like RetroTherm® LITE or Backer Board use a 20mm, pre-grooved XPS insulated panel that acts as both the pipe carrier and heat-conducting surface, suitable for all floor coverings. These lightweight systems are ideal for upper floors, keeping floor height build up to a minimum which not overloading joists.
What to Think About Before You Decide
Floor finish: Hard floors like tile or LVT make UFH significantly more effective. If bedrooms are to be carpeted in a thicker pile carpet, radiators may remain the better choice for those rooms.
Floor height: In existing homes, any increase in floor level can have a knock-on effect on doors, thresholds, and skirting boards.
Structural loading: Adding screed to an upper floor is not always possible without structural assessment.
Heat source compatibility: UFH works beautifully with heat pumps, which operate at lower flow temperatures — ideal for the lower water temperatures UFH systems run at. If you’re considering a heat pump alongside your UFH, this is well worth discussing during the design stage.
Cozia’s End-to-End Approach
At Cozia, we don’t just supply components, we design, supply, install, and where required, screed your underfloor heating system from start to finish. Every project begins with a bespoke design using AutoCAD software, produced to BS EN 1264 standards, so you know your system has been properly engineered for your home rather than put together from a template.
Whether you’re planning UFH throughout the entire house, just downstairs with radiators above, or a selective mix of both, we’ll give you honest, clear advice on the best approach for your property. No hard sell, no one-size-fits-all answers.
