Underfloor Heating: Water-Based vs Electric Systems

How water-based and electric underfloor heating work, which suits which room, and what to know about floor finishes, build-up height and controls.

Underfloor heating warms a room differently from a radiator: heat rises evenly from the entire floor surface, and the floor feels comfortable underfoot. Anyone considering it for a renovation usually starts with the same question: water-based or electric? The answer depends on room size, the home's heat source, the available floor height and how the system will be used.

Making this decision after finishes have been chosen is too late. Underfloor heating can change the entire floor build-up, door heights, thresholds and even what goes into the electrical panel. The system type should therefore be chosen at the very start of the design, when floor levels are set.

How water-based underfloor heating works

In a water-based (hydronic) system, pipes are laid in loops within the floor, usually in the screed, and hot water from a boiler or another heat source circulates through them. Each room's or zone's pipes connect to a manifold, which distributes flow and allows balancing.

Strengths of a hydronic system:

• it suits large areas and whole floors as the primary heat source;
• it works efficiently in a private house with a central heat source such as a boiler or heat pump;
• because it runs on relatively low water temperatures, it pairs well with modern condensing boilers and heat pumps.

There are limitations. The system needs considerable floor height: insulation, pipes and the screed above them take up several centimetres. Screed must be poured and allowed to cure fully, which extends the renovation schedule. In apartment buildings, connecting underfloor heating to the central heating system is often restricted by permits and technical conditions, so this should be clarified with the building management first.

How electric underfloor heating works

In an electric system, heat comes from a heating cable, a thin cable mat or infrared film. Cables and mats are usually embedded in tile adhesive or a thin screed, while film is laid under dry finishes such as laminate.

Advantages:

• installation is simple and adds little height;
• each room is controlled by its own thermostat;
• in a flat, it does not depend on the central heating system.

The main limitation is energy use. Heating a large area electrically for long periods raises running costs. That is why electric underfloor heating is mostly chosen as a comfort system: in bathrooms, kitchens, a child's play area or on a balcony. The system's load must match a dedicated circuit in the panel with RCD protection.

Choosing the floor finish

How well underfloor heating works also depends on what covers it. Ceramic tiles and natural stone conduct heat well and are considered the best match. For laminate, vinyl and engineered wood, check whether the manufacturer approves use over underfloor heating and what maximum surface temperature applies. Thick rugs and soft underlays hold the heat back and weaken the system.

Solid wood parquet is sensitive to changes in temperature and humidity; even where it can be used over underfloor heating, the material and installation conditions need particular care.

Furniture and layout

Loops or cables are not laid under fixed furniture. The area under kitchen units, wardrobes, a bath or a toilet is left unheated, because heat there is wasted and can harm the furniture. So the heating layout is drawn only once the furniture plan is final.

The floor temperature sensor should be installed so it can be replaced later, usually inside a conduit. The wall thermostat should be placed away from direct sunlight and other heat sources.

Quick comparison

• You need a primary heat source, there is a boiler and the area is large: a water-based system makes sense.
• You want warm floors in one or two rooms of a flat: an electric system is the simple answer.
• There is very little spare floor height: consider a thin electric mat or film.
• The schedule is tight: allow for screed curing time.

With both systems, a test is carried out after installation and before the finish is laid: a pressure test for hydronic loops, a resistance measurement for electric cables. Keep the results and a drawing of the cable or pipe layout together with photos.

Zaferoğlu İnşaat plans underfloor heating together with floor finishes and furniture layouts in apartment and villa renovations. Tell us whether the house has its own boiler and which rooms you want heated underfoot, and we can compare water and electric systems on those answers.