Koala can be used as a standalone cross-platform app that allows construction entry with a table form. It is distributed as an MSI installer for Windows or DMG for macOS.
Alternatively, Koala for Rhino supports full 3D heat transfer analysis by modeling volume blocks with assigned materials.
Since app notarization requires a paid Apple Developer account, users will have to use the following workaround.
This method allows you to manually authorize a specific app without lowering your overall security settings.
The KOALA interface is designed to be intuitive and efficient. The main window is divided into three primary areas:
Before creating a construction, you need materials. KOALA comes with a standard library, but you can create your own.
Navigate to the Materials tab. Click "New Material" to define properties like Thermal Conductivity (λ), Density (ρ), and Specific Heat Capacity (cp).
The Construction Editor is where you define the geometry of your building assembly.
You can add layers to your assembly. Each layer can be:
Every construction requires Surface Film Resistances to account for the thin layer of air clinging to the surface.
KOALA automatically adds these layers to your construction stack. You do not need to model them as material layers, but you can adjust their values in the Properties Panel if simulating floors or roofs.
KOALA performs two types of thermal simulations simultaneously: a Steady-State Analysis and a Dynamic Analysis (ISO 13786).
The solver calculates heat flow based on the temperature difference (ΔT) between the indoor and outdoor environments.
The solver discretizes your construction into a 2D mesh of rectangular finite elements. It solves the steady-state heat diffusion equation to determine the temperature at every node. This is crucial for identifying thermal bridges—areas where heat bypasses insulation (like through steel or wood studs), significantly reducing the wall's effective performance.
In addition to the static U-value, KOALA computes dynamic thermal properties according to the ISO 13786 standard. This simulates how the wall reacts to fluctuating outdoor temperatures over a 24-hour cycle, which is essential for understanding thermal mass and time lag.
KOALA bridges the gap between detailed component analysis and whole-building energy simulation.
You can export your construction as an EnergyPlus Input File (.idf). This export generates an approximate "equivalent layer" representation of your complex 2D assembly that can be used in energy models.
Note: This export uses "equivalent homogeneous layers" to mimic the thermal mass and resistance of the 2D assembly.
While the standalone Koala application offers a quick and easy table form entry for layered constructions, the Koala for Rhino plugin takes your analysis capabilities into three dimensions.
Koala for Rhino supports full 3D heat transfer analysis by modeling volume blocks with assigned materials. This allows you to evaluate complex geometric intersections, corners, structural penetrations, and custom architectural details that cannot be easily captured in a 1D or 2D table format.
The easiest way to install Koala for Rhino is through the built-in PackageManager command. Search for "Koala" and click install.
After installation, you must restart Rhino for the plugin to load
properly. Once restarted, simply type the KOALA command into the Rhino
command line to begin. A panel with a layer editor and simulation controls will appear.
The layer editor is used to assign materials and boundary conditions to the geometric volumes in your document. An important feature of the KOALA solver is how it handles intersections through layer priorities during the voxelization process.
Layer order matters: Layers higher up in the list have priority over lower layers. This is an extremely useful feature that allows modelers to draw volumes that intersect each other without having to perform tedious boolean operations. For example, if you have small metal fasteners that protrude through a layer of insulation, you just need to ensure the fasteners are placed on a layer that is higher in the list than the insulation layer. During voxelization, the fasteners will automatically carve their volume out of the insulation.
The Koala UI Panel consists of several key sections: