Because of this, you can change your home heating and cooling system air filter models without undermining clog-detection performance. The FILTERSCAN WiFi connects to the wireless router in your home. For more information, see How to Install, Calibrate and Operate the FILTERSCAN Air Filter Monitor.
Upstream: This refers to installing the air filter monitor on the cold-air return duct before the filter and blower.
When you install the air filter monitor downstream, you place it on the cold-air return duct after the filter, and before the blower. This is the ideal location for installing the FILTERSCAN.
In this case, the air filter monitor is installed either before or after the filter and using the optional Tubing Kit. Set the slide switch to the Downstream position for differential mounting.