I built an under-the-door fan duct to lower bedroom CO2
Hi HN, This is my attempt to fix groggy mornings by lowering my bedroom CO2 from 1700 ppm to ~900 ppm. I designed a simple, 3D-printed fan duct that directs air under the door to improve air circulation. A note on the design process: I used CadQuery, a Python library for creating parametric 3D models. I didn't know tools like this existed and highly recommend it if you can program; it turned out to be more convenient than manually iterating on prototypes in a GUI. The project is open source and the post explains the full build. Happy to answer any questions.
In plain words
This is an open-source 3D-printed fan duct designed to improve bedroom air circulation by directing airflow under doors, reducing CO2 levels from around 1700 ppm to 900 ppm to address grogginess. The maker used CadQuery, a Python library for parametric 3D modeling, to design the duct, highlighting it as an efficient alternative to traditional CAD software for programmers. The full build instructions and design files are available open source.
written from the facts on this page · September 2026
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