Various devices, systems, and methods may be presented. A sensor unit may be presented that includes a housing and a chamber arranged within the housing. The sensor unit may include a controller arranged within the housing. The controller may receive information from an HVAC (heating ventilation and air conditioning) system, wherein the information is indicative of operation of the HVAC system. The controller may determine an effect of the HVAC system on measurements made by the sensor using the information from the HVAC system.