How to make underfloor heating
WhereWater and heating
Steps
- In the Zones and thermostat row, choose a zone: Hydronic floor heating, Cable or Infrared heating film.
- Draw it on the plan. The Floor heating zone window opens on the right, with Drawing method in it:
- Rectangle: drag with the mouse, anything beyond the wall is trimmed off. A click without dragging gives the zone the whole room, even an L-shaped one;
Point by point: click the corners of the outline, they stick to the walls. Close it by clicking the first point, with Enter or with a double-click.
- In 3D, a zone is placed with a click on a room, covering the whole room.
- Hydronic floor: place a manifold (the row) and click Build in the Manifold pipes step. In the zone window, choose the laying pitch (15 cm by default).
- Electric floor: in the zone window, enter the specific power, W/m², and place a thermostat in the room (the Thermostat tile; it is also in Electrics).
- To adjust the outline, select the zone: circles appear at the corners, small squares on the sides. You can move, rotate and copy the zone, but it will not go beyond the wall.
- Wall heating is placed from the row: it is a strip on the wall, its width and height define the heating part. Enter the specific power, W/m², in the window.
Zone keys: rectangle
| What to press | What happens |
|---|---|
| Drag | drag: rectangle along the walls |
| Click | click: whole room |
| Esc | turn the tool off |
Zone keys: point by point
| What to press | What happens |
|---|---|
| Click | place an outline corner |
| Shift | side strictly horizontal or vertical |
| Backspace | remove the last point |
| Enteror×2Double-click | close the outline (or click the first point) |
| Esc | reset the outline; again: turn the tool off |
Zone editing keys
| What to press | What happens |
|---|---|
| Drag | by a circle: moves the corner |
| Drag | by the square in the middle of a side: adds a corner (a click in the middle, drag where you steer) |
| ×2Double-click | on a circle: removes the corner |
What is important to know
- The zone's area is written in its middle, the side lengths next to the sides. Lengths are in the project unit, like room dimensions: in millimetres without a label, in centimetres and metres with one. Sides lying on walls are labelled by the room dimension. A zone covering the whole room does not write its area: its area is the room area.
- The floor is no warmer than 29 °C in rooms and 31 °C in bathrooms and corridors (SP 60, cl. 14.18). If such a floor does not cover the heat loss, a radiator is also needed.
- Hydronic floor: a loop no longer than 100 m (manufacturer data), heat carrier no hotter than 50 °C, with hot supply a mixing unit is needed. An electric floor is no more powerful than 200 W/m² (manufacturer data).
- Under a bathtub, shower tray, toilet and cabinets the floor is not laid: the calculation will say so.
- Wall heating warms like an electric convector. Its surface is no warmer than 40 °C (SP 60, cl. 14.18); the calculation estimates it as t_in + W/m² ÷ 8.7 (coefficient from SP 50.13330.2024, Table 4). Heating elements are placed only in a multilayer exterior wall (cl. 14.17).