An air purifier that measures what matters, cleans your air, and shows you what's happening — no phone, no squinting, no cloud account.
It purifies your air. A true HEPA H13 filter captures 99.97% of particles down to 0.3 microns. The fan adjusts itself based on what the sensors are reading — faster when the air is bad, quieter when it's clean.
It monitors your environment. Eight sensors measure PM2.5, PM10, CO2, VOCs, temperature, humidity, pressure, and light. Each one is there because the reading is useful — not to pad a spec sheet.
It respects your privacy. No cloud account. No telemetry. Linden runs on your local network, and your data stays on the device. If we disappeared tomorrow, it would keep running.
Chosen to age well, not to hit a price point.
Hand-finished crown and accent panels. Every unit looks slightly different because real wood does.
Machined and anodized enclosure. Conducts heat away from electronics. Doesn't yellow, crack, or creak.
3.7-inch e-ink screen. Readable in direct sunlight. Zero power draw between refreshes.
Sensirion and Bosch sensors. Calibrated on-device.
Your air quality, sensor readings, and system status — always visible, no phone required.
It looks like paper behind aluminum. Because it basically is.
Most air purifiers require an account, an app, and a cloud connection. Linden needs none of them. Your data lives on the device — export it anytime as CSV or JSON.
The device pulls outdoor air quality data from the EPA every hour and compares it to what's inside your home.
When wildfire smoke pushes outdoor PM2.5 to 80 and your indoor reading is 8, you can see exactly what the filter is doing for you.
Set fan schedules by time of day — quiet at night, responsive during the day. Or let it figure it out from CO2 levels and network presence.
When CO2 drops and the room empties, the fan slows down. When you walk back in, it ramps up. No extra hardware — it uses what it already knows.
We design the enclosure, source the components, assemble the boards, and test every unit ourselves.
When something can be replaced, repaired, or upgraded, we design for that. The HEPA filter slides out with a magnetic panel. The software updates over your local network.
The American linden — called basswood in Wisconsin, where we build Linden — is one of the most common trees in the state's forests. Scientists use its broad, heart-shaped leaves to measure urban air quality because they capture particulate matter with remarkable efficiency.
For centuries before that, communities gathered under linden trees to hold court, because tradition held that no one could tell a lie in its shade. Its wood is the choice of master carvers — prized for its fine grain and the way it responds to skilled hands.
We thought all of that sounded like a good name for something you trust with the air your family breathes.
The full list.
Linden is in active development. We'll email you when prototypes are ready.
Email notifications aren't wired up yet — we're building in the open. Check back soon.