We have a new home with a Trane XV-18 system. In addition to its efficiency, it is touted to to be able to control humidity down to 45%. However, it has proven that it is worse at controlling humidity than all the single-stage systems we've owned before, so there must be a problem with its configuration, programming, or design. The installers here are completely incompetent, and the Trane support employees don't know anything, so it's up to us to resolve the issue. I was just examining the installation of the unit, because our house has had so many installation and wiring issues due to the incompetency of our contractor and all sub-contractors involved with building the house. I noticed the air handler does have an auxiliary heating element that appears to have never been used, even throughout the entire winter with temperatures dipping into the 20's. Is that heat-strip/auxiliary heating element only used for heat, or is it also intended to be used for dehumidification as well?