> For the complete documentation index, see [llms.txt](https://docs.betterbuilding.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.betterbuilding.io/sign-up-and-plans/news-and-updates/2026/a-new-hygrothermal-solver-and-goodbye-energyplus-hamt.md).
# A new hygrothermal solver (and goodbye, EnergyPlus HAMT)
A few years ago we went all in on EnergyPlus HAMT simulations, built on the back of Künzel's seminal 1994 work on heat and moisture transport.
The goal was to use the value already sitting inside EnergyPlus to make hygrothermal modeling, and in our case the assessment of condensation risk in walls, more available to more people and a little less painful to actually get an answer out of.
That worked, for a while.
But as we added features year after year, we kept running into the same wall (pun intended). Our requirements, and yours, were constantly bumping up against the limitations of EnergyPlus HAMT. None of them were dramatic on their own. They were just small, important things that quietly added up.
Over time it became clear that EnergyPlus didn't have a clear development priority for hygrothermal simulation. That's fair enough, it's an enormous simulation engine with a lot of competing demands, but it left us asking what was actually best for Better Building going forward.
The answer turned out to be the obvious one: build our own. We started six months ago, and it's being released next month.
For those looking to gain access early, we are collecting your interest via the link below.
Register for Early Access
### The Better Building HAMT Solver
The short version is that we now have our own hygrothermal solver, and it is fully validated. It passes the [HAMSTAD ](/support-and-training/other-support/testing-and-verification/hamstad-benchmark-test-report.md)and [EN 15026 ](/support-and-training/other-support/testing-and-verification/bs-en-15026-2023-hygrothermal-performance-benchmark-test.md)benchmarks along with the other benchmark exercises that any comparable downloadable package would be expected to meet.
In practical terms, we're no longer limited by the small but important gaps in EnergyPlus HAMT. We can now state alignment with the ASHRAE 160 and DA07 standards directly, which means compliance work and building improvement can both be resolved inside the new solver, with full confidence, for wall and roof systems alike.
We've been testing for a month now, and we're happy with where things are landing. Our results line up with the other hygrothermal software on the market, which is exactly what you want to see from something this new.
### What changes in July?
Toward the end of July, you'll see two things.
First, a formal sunsetting of our EnergyPlus HAMT simulations.
Second, a real speedup. You'll be able to run multiple orientations parametrically and get hygrothermal results back in around 60 seconds, with the report written for you.
This is a big step. But it isn't the only one we're taking toward more detail-oriented building environments, so think of it as the first of a few.
Register for Early Access
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