How it works

Inputs, a section through the room, a result as a tendency. This page explains what is calculated, what is assumed and where the model stops.

1. Inputs

You enter the outdoor temperature, the room temperature, the relative humidity in the room and a wall template (for example an uninsulated or an insulated outside wall). You also place a window, a radiator and furniture at fixed positions in the section.

2. The 2D section

The app calculates two things, separately:

• Wall surfaces. The temperature of the wall surface comes from steady-state heat conduction through the wall, calculated as a case with common boundary conditions. Behind furniture, a higher surface resistance is assumed, because less warm air reaches the wall there.
• Air in the room. The air movement, such as the circulation above the radiator or cool air sinking at the window, is a simplified two-dimensional picture. Real room air is three-dimensional and turbulent. This layer therefore shows mechanisms, not numbers.

The perceived temperature at two fixed positions in the room is a tendency derived from the air temperature and the temperatures of the surrounding surfaces, with simplified radiation.

3. The result

For the wall surface, the app shows a risk assessment in three levels with a range, based on common design values, not checked against standard texts. It shows where the wall gets critically cool in the model. It does not say whether mould will grow on a real wall, or why.

Where the values come from

Every number in the app is labelled:

• calculated – a result of the simulation from your inputs,
• common assumption – a widely used design value, for example for heat transfer at surfaces,
• team assumption – a value we have set as long as no reliable source is available. The app says so.

Limits

• Two dimensions instead of three. Corners, roller shutter boxes and junctions in the room are missing.
• Steady state: no daily cycle, no ventilation, no heat storage in the wall.
• The wall is a template, not the real build-up of a particular house.
• The air movement is qualitative. The app does not derive statements about draughts in a real room from it.
• The app does not replace an on-site measurement or an expert report.

If you can see mould: consult a qualified building surveyor.