Floor heating — temperatures, loops and material consumption

Floor heating distributes heat over the entire floor surface at low temperature. This provides a pleasant, even heat picture and combines well with heat pumps because the low flow keeps SCOP high. Dimensioning follows DS 469 (heating and cooling systems) and DS/EN 1264 (water-based floor heating systems).

Surface limits come from DS 469 / EN 1264 and are about comfort and not damaging the floor covering. The higher ceiling in bathrooms reflects the desire for a warm floor there. (Source: golan.dk floor heating report 2025 — advisory summary.)

• 0116 mm pipe: recommended max. approx. 100 m per circuit.
• 0220 mm pipe: up to approx. 120–150 m per circuit (verify against manufacturer data).
• 03Material consumption: approx. 5 m floor heating hose per m² at 16 mm and c/c 200 mm (indicative).
• 04Max. pressure difference across distributor: approx. 20 kPa (0.2 bar) (indicative).

Water floor heating incl. specialist costs approximately 900–2,400 kr./m² depending on structure (cast-in, track plate, milled in existing floor). (Source: badevaerelsepriser.dk, June 2026 — indicative.)

Radiant heating is dimensioned backwards: start with the room's heat demand (W/m² at design outdoor temperature), find the required heat output, and then choose c/c spacing and flow temperature that can deliver that output without exceeding surface limits. EN 1264 provides characteristic and limit curves that bind heat output, mean water temperature, c/c and floor covering together.

• 011) Determine the room's heat requirement [W] and divide by floor area → necessary surface power [W/m²].
• 022) Check that the surface effect stays below the limit (~100 W/m² in the occupancy zone). If the requirement cannot be met, supplement with radiator or extra area.
• 033) Choose c/c spacing: closer c/c (e.g. 100 mm) gives higher and smoother effect than wide (e.g. 300 mm).
• 044) Find the required mean water temperature (and thus flow) from the EN 1264-performance diagram for the chosen c/c and floor finish.
• 055) Calculate loop length and flow per circuit and check pressure loss and differential pressure across the distributor.

The covering on top of radiant heating is an insulating barrier that must »be seen through«. EN 1264 accounts for the thermal resistance of the floor covering R_λ,B and draws characteristic curves for the values 0, 0.05, 0.10 and 0.15 m²K/W. The higher R_λ,B, the higher the flow temperature (or closer c/c spacing) required for the same heat output — a thick wooden floor or carpet »steals« output, which tiles do not.

The values are guidance; EN 1264 normally assumes thermal resistance up to 0.15 m²K/W. If exceeded, floor heating becomes ineffective, and closer c/c or higher flow temperature must be chosen. Use the actual R_λ,B from the floor product's datasheet. (Source: DS/EN 1264-2/-3.)