air quality
My New Bambu H2S Had Unhealthy Defaults
The first night I ran my new H2S, the printer room PM2.5 climbed into the EPA's Unhealthy range and stayed there for seven hours. The printer's carbon and HEPA filter was there the whole time, it just wasn't in the air path for PETG. Here's how Home Assistant caught it, the firmware setting that routes the exhaust through the filter, and how I got Home Assistant to tell me when it's on.
Sometimes a sensor lies about what model it is: the SEN55 that said SEN54
Some AIR-1 units report themselves as a SEN54 over I2C even though the module inside is a SEN55, so ESPHome shut their NOx sensor off. It turned out NOx had never worked on those units at all. A small override option settled whether the hardware or the register was lying, and it ships in ESPHome 2026.7.2.
Building an air quality LED indicator for the AIR-1
The AIR-1 has three onboard RGB LEDs, so I made them show air quality at a glance. The feature itself is small. Getting there took longer than it should have, because I kept fixing things that weren't the problem. These are the dead ends and where it ended up.
Two days of ceiling dust, measured in eight rooms
I spent two days cutting sheetrock, disturbing old insulation, and scraping popcorn ceiling in the upstairs bathroom, with eight Apollo AIR-1 sensors watching the whole house. The two rooms off the bathroom spiked 20 to 30 times over, and the return air lifted every other room too. The room-by-room data, and why I wore a P100 the whole time.