Calculating thin-layer underfloor heating

Calculate the complete material requirements for your NerthusFlow thin-layer system in 3 steps – studded membrane, PE-RT heating pipe, CAF flow screed (Planogel Rheo) and edge insulation strips. The thin-layer system is suitable for old buildings and renovations: only 18–22 mm total height, no chiselling, heat pump compatible according to EN 1264. Enter your square meters – the configurator calculates the pipe quantity, number of heating circuits and the set price immediately.

What the configurator calculates – NerthusFlow thin-layer system

Based on your room area, the configurator determines the complete material requirements:

  • NerthusFlow dimpled sheet (10mm, 14mm or 16mm variant): Room area + 5% waste
  • PE-RT EVOH heating pipe: approx. 6.7 m/m² with 15 cm pipe spacing (living area), 10 m/m² in the bathroom
  • Heating circuits & manifold: max. 80 m per circuit – for 80 m² typically 7 heating circuits
  • CAF flowing screed Planogel Rheo: approx. 15–20 kg/m² depending on coverage
  • Edge insulation strip: Room perimeter in linear meters

Example calculation for 80 m²: 84 m² dimpled sheet · 540 m heating pipe (7 heating circuits) · 1,200 kg Planogel Rheo · 50 linear meters edge insulation strip – complete set from approx. €2,000.

Häufige Fragen

How much heating pipe do I need for an 80 m² thin-layer system?
For a laying distance of 15 cm (standard), you will need approx. 540 m of PE-RT heating pipe for 80 m² – distributed over 7 heating circuits of max. 80 m each. In the bathroom, with a laying distance of 10 cm, calculate with 800 m/80 m². The configurator automatically outputs the exact pipe quantity and circuit division.
What is the price of the NerthusFlow thin-layer system as a complete set for 100 m²?
The NerthusFlow thin-layer system complete set (dimpled sheet, heating pipe, Planogel Rheo, edge insulation strips) costs from approx. €25/m² – so for 100 m² this would be from approx. €2,500. A set discount is automatically applied in the configurator for certain order values (€800/€1,500/€2,000).
How many heating circuits do I need for the thin-layer system on 100 m²?
For 100 m² and a laying distance of 15 cm, you will need approx. 670 m of heating pipe – this corresponds to 8–9 heating circuits (max. 80 m per circuit). You will need a heating circuit manifold with at least 9 outlets. The configurator automatically calculates the number of circuits and the appropriate manifold.
Thin-layer system or hook-and-loop system: Which is better for old building renovation?
For level subfloors (tiles, screed), the hook-and-loop system (from €18/sqm, 19 mm build-up) is the more economical choice – no screed, immediately walkable. The thin-layer system (from €25/sqm, 18 mm) is ideal for uneven subfloors: Planogel Rheo compensates for unevenness of up to 10 mm and offers better thermal conductivity for heat pumps.
How do I calculate the amount of CAF screed (Planogel Rheo) for the thin-layer system?
For the NerthusFlow thin-layer system, estimate 15–20 kg of Planogel Rheo per m² (5–10 mm coverage over the pipe). For 80 m², this means 1,200–1,600 kg. The configurator calculates the exact quantity based on your room area and the selected NerthusFlow variant.