High Efficiency Furnace vented through the roof. How screwed am I?
All of the units I have installed the condensate in the exhaust drains back to the firebox and drains with that condensate. The pipe if run horizontally is supposed to have a slope. So I do not see a problem. Adding an ac coil or evaporator should not affect the heat system exhaust unless it needs to be re routed you can add the ac drain to your condensate pump but I would install a sensor to alarm if the pump fails. So you know because both systems can make quite a mess when the pump fails and they do fail.