Usually HVAC heat exchangers pretty close to an exterior wall, because the run to the exterior heat exchanger is ideally not too long, so you can tap into the r

Usually HVAC heat exchangers pretty close to an exterior wall, because the run to the exterior heat exchanger is ideally not too long, so you can tap into the return plenum there. But even if there’s not, there’s some flexibility in where you tap in (though some places might be more ideal than others). For us, it was just a couple 6”holes in the cinderblocks of a basement wall (at least 6 feet apart).