How about retrofits? I agree with you that a well balanced system with HRV or ERV is ideal, but How does one talk to the homeowner that they should fork above an extra $two-3K for one? I've tried using each adding a duct to the outside and putting a greater http://lukascqziq.onesmablog.com/The-Positive-Pressure-Ventilation-Systems-Diaries-23554122