AirGradient builds open-source indoor and outdoor air quality monitors that track PM2.5, CO2, temperature, humidity and other pollutants. The company is known for its open hardware and firmware, letting users build, repair and integrate the monitors with platforms like Home Assistant and its own dashboard. AirGradient appeals to people who want transparent, data-driven air quality monitoring rather than a closed black box.
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Refoss is a smart home brand active since 2016, best known for its multi-channel energy monitors and for smart plugs, switches and garage door openers. Its energy monitors clamp onto the mains and branch circuits and expose the readings through a local web UI, an open JSON-RPC API and MQTT, so they run without any cloud account. Refoss devices integrate natively with Home Assistant, Alexa, Google Home and Apple HomeKit.
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