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Getting started

Installation

idfpy needs Python 3.12 or newer. EnergyPlus itself is only required for running simulations; reading, editing and validating models works without it.

pip install "idfpy==26.2.*"

uv add "idfpy==26.2.*"

Pick the idfpy series that matches the EnergyPlus version of your models. The installed version reports the EnergyPlus schema it was generated from:

from idfpy import IDF

IDF().version  # '26.2'

Load, edit, save

from pathlib import Path

from idfpy import IDF
from idfpy.models import Zone

idf = IDF.load(Path('existing.idf'))  # format detected from the extension

zone = idf.get(Zone, 'Zone1')         # typed as Zone | None
zone.multiplier = 2                   # validated on assignment

idf.save(Path('modified.idf'))

Query methods accept the model class, its Python class name ('BuildingSurfaceDetailed') or the EnergyPlus type name ('BuildingSurface:Detailed'). Passing the class keeps precise types in your editor.

Run a simulation

from pathlib import Path

from idfpy.sim import simulate

result = simulate(
    Path('modified.idf'),
    weather=Path('USA_IL_Chicago-OHare.Intl.AP.725300_TMY3.epw'),
    output_dir=Path('results'),
)
print(result.success, result.err.severe_count if result.err else None)

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