At a glance Expert’s RatingProsMeasures your indoor air quality and triggers compatible smart thermostats to run your HVAC system’s fan as neededTracks HVAC system’s air filter’s useful life and alerts when it needs to be replacedFilters are easy to install in a permanent sensor frameSensor frame can provide early warnings of HVAC system problemsConsProprietary filters ($22 each) are only available from Woosh AirSensor frame left problem-causing gaps in our reviewer’s HVAC system’s filter slotLimited number of compatible smart thermostatsHVAC system problem warnings are sent via email, not pus…