​The two tools match on core physics and standards coverage; they differ most on delivery, speed and roadmap.
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​The Better Building HAMT Solver has been tested against two independent benchmarks: HAMSTAD and the BS EN 15026:2023 hygrothermal performance benchmark tests. These are the standard checks that any transient solver should pass, and the published results are available from Better Building.​

A second round of testing used WUFI Pro 6.6 as the reference. It focused on features that sit outside what HAMSTAD and EN 15026 verify: moisture sources, rain exposure, rain deposition, Sd values, short and long wave radiation, explicit radiation and the adhering fraction of rain. A consistent, strong relationship was found between the two software outputs in all cases.​

This matters for a reader choosing between tools. Agreement with WUFI means results are comparable with the tool many practitioners already know, while independent benchmark verification means that agreement is not simply two solvers sharing the same assumptions.​

For fairness, WUFI's advantage here is track record: it has been used on a very large number of projects and is familiar to reviewers and certifiers. Better Building's answer is transparency, with its test results published and its inputs aligned to the same standards.

Better Building covers the physics a credible hygrothermal assessment needs, and covers it in a form that is easy to apply.​

‍Material physics. The solver uses dry bulk density, specific heat capacity, porosity, thermal conductivity with moisture dependence, vapour diffusion resistance (dry cup and wet cup), the moisture storage function up to free water saturation, separate liquid transport coefficients for suction and redistribution, and the water absorption coefficient. Thermal conductivity, vapour resistance and liquid transport are all treated as moisture-dependent. A database of common building materials with calibrated hygrothermal properties is included, and every parameter can be overridden with manufacturer test data.​

‍Layers and membranes. Vapour barriers, retarders and permeable membranes are represented by diffusion resistance factors or Sd values. Moisture-adaptive membranes, sometimes called smart vapour retarders or AVCLs, are supported with their humidity-dependent behaviour. Sealed air layers and ventilated cavities are both modelled, which suits rainscreen cladding and ventilated roofs.​

‍Boundary conditions and loads. Orientation and inclination are set per assessment. Wind-driven rain, explicit radiation for radiative cooling, and short and long wave radiation are included. Moisture sources can be placed inside the assembly to represent construction moisture or defined water ingress, and initial temperature and moisture content can be set per layer to stress test a wall or roof.​

‍Where WUFI still has an edge. WUFI's long history means a deep library of material data, a large body of published case studies, and wide familiarity among reviewers. Better Building currently limits an assembly to 10 layers and a single run to 10 years, which covers the large majority of assessments but is a boundary worth stating. Most credible assessments run five years minimum, so the cap rarely bites in practice.

Better Building was built with ASHRAE 160 and DA07 as its primary modelling basis, so every input and output those standards call for is available on the platform. Because DA07 is the pathway for condensation management under the National Construction Code, the solver enables all inputs, calculations and outputs needed to meet NCC 2022 and 2025. The same inputs can be used internationally.​

The standards play different roles, and the platform is organised around that. EN 13788 is the steady-state Glaser check, quick but blind to rain, storage and liquid transport. EN 15026 is the transient standard behind proper simulation. ASHRAE 160 fixes the inputs, such as indoor humidity and rain deposition, and supplies explicit mould criteria.​

The practical benefit is that an assessor starts from compliant defaults rather than assembling them. Reference years can be run for both cold winter condensation and hot summer inward vapour drive, and results are read against stated criteria such as moisture content limits for wood-based sheathing and mould risk at vulnerable interfaces.​

WUFI is equally capable of supporting ASHRAE 160 style assessments. The difference is that Better Building packages the Australian DA07 and NCC context directly, which shortens the path from model to compliance submission for local practitioners.

The clearest advantage of Better Building is how quickly a reliable assessment gets done. A typical wall is modelled in less than a few minutes, including the simulation, results and reporting, and the whole process runs in the cloud.​That has four practical consequences.​​

‍No installation or licence management. A project starts from a browser, with a 30-day trial available, so a new team member or collaborator is productive the same day.​

‍Compute stays off the user's machine. Long transient runs of several years do not tie up a laptop, and results are available wherever the user signs in.​

‍Reporting is part of the workflow. Inputs, results and criteria sit together, so the assessment can be reviewed and defended without a separate documentation step.​

‍Faster iteration. Because a wall takes minutes, it is realistic to sweep the sensitivities the documentation itself recommends: cavity air change rates, surface absorptivity, reference years and initial moisture conditions. Conclusions that survive a sweep are far more robust than a single run.​

A desktop tool can match the solver speed on a good machine. What it cannot match is the combination of zero setup, shared access and built-in reporting that a cloud platform provides.

A balanced comparison has to name the limits, and several are shared by any one-dimensional hygrothermal tool.​

‍Shared limits. A 1D model cannot represent thermal bridges such as corners, balcony slabs, lintels or studs. It moves moisture by diffusion and capillary flow, not by air leaking through gaps, so a clean result assumes a truly airtight build. Material data are generic unless measured, the climate file is representative rather than predictive, and the output is moisture and humidity over time, not a pass or fail verdict. Salt chemistry and efflorescence are not simulated directly.​

‍Better Building today. Assemblies are limited to 10 layers, runs to 10 years, and geometry questions that need 2D or 3D, such as junctions and window reveals, are not yet covered. Wind-driven rain also depends on precipitation being present in the climate file, and very wet materials or coarse build-ups can trigger convergence warnings that need review.​

‍WUFI today. Its main constraints are practical rather than physical: local installation and licensing, a more manual reporting step, and a desktop workflow that is harder to share and review across a team. Two-dimensional analysis is available as a separate product rather than an integrated workflow.​

The honest summary is that Better Building's present limits are mostly the limits of 1D modelling itself, and the geometry gap is the one actively being closed.