In hot and humid areas an Energy Recovery Ventilator (ERV) should be chosen as it's able to remove moisture from the incoming air as well. There are a number o

In hot and humid areas an Energy Recovery Ventilator (ERV) should be chosen as it's able to remove moisture from the incoming air as well. There are a number of companies that make whole house ERV/HRV kits and a good method of setup is to constantly exhaust your bathrooms and possibly other contaminated spaces, while delivering fresh air to bedrooms or common areas. Energy recovery is in the 50% range. Some can be balanced to slightly positive pressure particularly if there is an attached garage or other sources of contamination. ASHRAE publishes standard 62.2 which recommends that for modern houses the ventilation rate in CFM = 0.03*ft^2 + 7.5(Nbedrooms+1)