I do not have a a/c drain pipe on the side of my house. Where do I need to look?

I'd start my looking in and around your furnace. It probibly drains into a floor drain near it.

Air condition condensation drains often empty into a floor drain or into some other plumbing drain. Follow the condensation piping from the a/c unit to see where it drains.

Could be into a condensate pump and into your sewer line.

I've some installers drill through the fascia & run the drain into the rain gutters if the air handler is in the attic.