🧱 Materials
37 built-in materials organized by category, plus full support for custom user-defined materials.
Overview
Every region in your model must have an assigned material. Materials define the thermal conductivity (λ, W/m·K) used by the FEM solver. Each material also has an emissivity value (for radiation calculations) and a display color used on the canvas and in results overlays.
Thermal conductivity values follow EN ISO 10456 design values.
Material Categories
Materials are organized into four categories:
- Solid — Dense structural materials (concrete, steel, aluminum, brick, glass, etc.)
- Insulation — Thermal insulation products (EPS, XPS, mineral wool, PIR, phenolic)
- Glazing — Glass products used in fenestration
- Gas — Cavity fill gases (air, argon, krypton) used in glazing units
Built-in Material Database
ThermX ships with 37 built-in materials:
Solids
| Material | λ (W/m·K) | Category |
|---|---|---|
| Concrete | 1.80 | Solid |
| Reinforced Concrete | 2.30 | Solid |
| Brick (clay) | 0.77 | Solid |
| Lightweight Concrete Block | 0.30 | Solid |
| Mortar / Plaster | 0.87 | Solid |
| Steel | 50.00 | Solid |
| Stainless Steel | 17.00 | Solid |
| Aluminum | 200.00 | Solid |
| Timber | 0.13 | Solid |
| Plywood | 0.13 | Solid |
| Gypsum Board | 0.25 | Solid |
| OSB | 0.13 | Solid |
| Glass | 1.00 | Glazing |
| PVC | 0.17 | Solid |
| EPDM / Rubber | 0.25 | Solid |
| Polypropylene | 0.22 | Solid |
| Polyamide (PA 6.6) | 0.25 | Solid |
| Polyethylene | 0.33 | Solid |
Insulation
| Material | λ (W/m·K) | Category |
|---|---|---|
| EPS (Expanded Polystyrene) | 0.037 | Insulation |
| XPS (Extruded Polystyrene) | 0.034 | Insulation |
| Mineral Wool (MW) | 0.035 | Insulation |
| PIR (Polyisocyanurate) | 0.023 | Insulation |
| Phenolic Foam | 0.021 | Insulation |
| Cellulose (blown) | 0.040 | Insulation |
| Cork | 0.040 | Insulation |
| Aerogel | 0.015 | Insulation |
| Vacuum Insulation Panel (VIP) | 0.007 | Insulation |
Gases
| Material | λ (W/m·K) | Category |
|---|---|---|
| Air | 0.024 | Gas |
| Argon | 0.016 | Gas |
| Krypton | 0.009 | Gas |
| Xenon | 0.005 | Gas |
For glazing cavities, gas conductivity values represent the effective thermal conductivity of the sealed gas fill in the context of conduction-only analysis (radiation is handled via emissivity).
Assigning Materials
- Select a region with the Select tool (
V) - Open the Materials panel in the right sidebar
- Click a material to assign it to the selected region
- The region immediately updates its display color on the canvas
You can also assign materials to multiple regions at once: hold Shift and click additional regions to build a multi-selection, then pick a material.
Custom Materials
ThermX supports fully user-defined materials with custom thermal properties:
- Open the Materials panel and click + New Material
- Enter a name, thermal conductivity (λ in W/m·K), and emissivity
- Choose a display color for the canvas
- Select a category (solid, insulation, glazing, or gas)
- Click Save — the material is now available in your project
Custom materials are stored in the project file (.therm.json) and travel with the file when shared.
Material Properties
| Property | Unit | Description |
|---|---|---|
| Name | — | Display name shown in panels and legends |
| Conductivity (λ) | W/(m·K) | Thermal conductivity used in the FEM equations |
| Emissivity (ε) | 0–1 | Surface emissivity for radiation calculations |
| Color | Hex/RGB | Display color on canvas and results overlays |
| Category | — | solid / insulation / glazing / gas |
Materials Legend
The canvas displays a Materials Legend overlay listing all materials used in the current model with their color swatches and names. This legend is also included when exporting to PDF from the Sheets tab.