Your heating and cooling systems have many components that work together to provide optimal home comfort. Steps required to retrofit air conditioning to your existing furnace. You cannot connect a condensate drain line to a waste line since the air. If your home is not equipped with an AC system, you have several options available depending on the size, location, and build of your home.
Advantages to Adding AC to an Existing Furnace You will have to add a conduit to connect your indoor and outdoor units and supply.
Wire colors with HVAC wiring are non-standardized, so the colors themselves don't help much. Your furance/air handler should have a control.
If you have heat and AC, you'll need 18/5. If you find a C-wire in your furnace, then the other end is probably stuffed into the wall behind your thermostat. As you can see in the photo above, this furnace does not have a C-wire hooked up.