We live here in the south with the ac on all the time. Our installer located the fresh air duct with our erv 2 feet off the ground in a shrub garden covered by pinestraw which of course is renewed over dead leaves ect. each spring. my question is, is this too close to the ground and might it draw up mold spores/fungus in the garden into the system. would it be better to place higher. our exhaust for erv to outside is 5 feet high and not over a garden. Could we reverse the two?