A single Airthings Wave Plus sensor (radon, CO2, VOC, humidity, temperature) costs $230. Most homes need 1-2 sensors (basement for radon, main living area for CO2/VOC). An Ecobee Premium thermostat with built-in air quality sensing runs $250. A complete Nestology air quality package with installation, sensor placement, smart home integration, and dashboard setup runs $500-$1,500 depending on home size and number of zones. Whole-home ventilation (AprilAire ERV) adds $2,000-$4,000 installed.