Warmup Convergence Error

1. The simulation has not run correctly because of this severe error: **
** ** Severe ** CheckWarmupConvergence: Loads Initialization, Zone=“E1” did not converge after 25 warmup days.


I am trying to simulate a courtyard typology with 32 zones involves. As soon as I try to connect the natural ventilation component, it starts producing the above mentioned error. Please find enclosed images . I hope you could help.




Can you please share a simplified version of your GH file?


Can you save as the rhino file in version 5 please?

Replaced the file.

I took a look at the file. It’s a complex file and needs simplification before someone can take a look. Kindly go through these guidelines and re-share a simplified version of the file please.

Hi Devang,

I went through the guidelines and simplified the file into 5 parts; geometry, profiles, internal loads, hvac/natvent and run simulation. I also internalized the geometry for ease and marked the boolean toggles to be made true. I hope it becomes understandable.

I also came across this other post from the forum, but didn’t seem to help the problem. (WarmupConvergence)

I also tried increasing the warmup days using simulation control, energy sim parameters components.
(image enclosed)

Please find the revised file in the following folder:

Thank You


hi,have you found any solution because i am having the same problem for the first time,even though i ran the simulation before with no warnings

does anyone know how to solve this?

I found this discussion, and it suggests to change Loads Convergence Tolerance Value .
Does anyone know how it can be done in honeybee?

I had the same “…did not converge after 25 warmup days.” error and solved it by increasing maxWarmupDays_ as shown in the screenshot below.

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I’m getting the same error in HB-Energy 1.2.0. It looks like the maxWarmupDays_ was removed from SimControls. How should I address this in 1.2.0?

Hey sleaman, I don’t know for certain but I feel whenever I get warm up error in 1.2 there’s something else wrong/not ideal in the script or geometry. Also try basic stuff like shutting everything down and reopening if the error came out of no where.
Hopefully someone who can answer your question specifically replies.

I’ll try to at least expose the warmup convergence limits on the SDK layer if not a LBT Grasshopper component. I opened an issue for it and I will close it when it gets addressed.

I hadn’t labeled it a high priority since increasing the warmup days usually didn’t result in convergence for a lot of my cases. But I know that’s just because many of my cases involved feedback loops between various building controls, especially natural ventilation controls. So just tweaking those controls often resulted in stable simulations.

Hi @chris,

Was wondering if access to limits of warmup convergence has been added to the SDK?

Thank you

Hi @HamidrezaSh ,

No, it has still not been added yet but I encourage you to just edit the 1 line in the IDF generated by Honeybee under the Building section, where you will find the maximum number of warmup days.

Then you can simulate the edited IDF with the HB Run IDF component. My guess is that, if it’s not converging after the default 25 warmup days, then it’s likely never going to converge at all and you should either accept this or change some of the controls in your Honeybee Rooms to make the conditions more stable.

If you find that increasing the number of warmup days actually solves your particular case and makes the warning go away, then I’ll prioritize exposing the warmup days more.


Hi @chris,

Thanks for the reply. I was initially thinking that increasing warmup days might help in my case because my study period was defined after a holiday period but as you said it did not help much.

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