We currently live in Ohio and are moving to Charleston, South Carolina this summer. We currently have an HRV attached to our Lennox variable speed gas furnace with the 16 MERV media filter. We are receiving conflicting opinions from some of the HVAC people down in Charleston about the benefits of the ERV. They say that it doesn't do enough to control humidity when the temp is in the mid-high 70s and the A/C isn't actively running, while our low-speed fan and ERV will be. They say that the ERV uses an exchange of air to try to dehumidify the incoming fresh air. I've been advised by one to forget the ERV and go with a dehumidification system that is always active and that will draw in outside air, dehumidify with drainage, and then exhale the old house air separately. My main concern is the indoor air quality of the house with a son with severe asthma. I realize that humidity will be a much bigger issue down there, but we will want to open our windows and doors more often with the mild weather. Suggestions?