Performed 3 System Maintenance. Installed 3 Nest Pro Tstats. After inspection I informed the homeowner that the entire basement system is outdated and out of code. The MainFloor and Upstairs furnaces were also older and not in the best of condition. An existing humidifier from original install needs to be removed or updated. The humidifier is currently not operational. The homeowner would like the office to call Monday to schedule a consultation to further discuss these matters.