HVAC pulls air in from the house (through what is often refered to as a cold air return), conditions it (heats or cools), and then blows it out into the house. Your HVAC must have some way to pull air in from the house or it will not work correctly. You want inside air to feed into the HVAC, not air from the outside.

Bruce

When my father, an HVAC engineer, designed the whole-house AC system for our Chicago house, he ran ducts to both a return grate inside the house and an outside return, with a movable vane to select which would be used, depending on outside conditions.

The return air should be coming from conditioned space. You should fix this ASAP.

Thanks

It should always be taking air from inside. This part of how the cooling process works as it helps take unwanted heat out of your living spaces.

Twintech Heating & Cooling

https://twintechheating.ca/