I've recently changed from a traditional vented dryer to a condenser machine (Bosch Axxis) So far, my experience has been very positive - it dries in pretty much the same amount of time as the washer takes to finish a load, so the pair work well.

I've been trying to suss out the best way to optimize the machine's efficiency. With a vented dryer, performance is all about airflow: straight vent, clean filter, etc. In this machine, clean filter and condenser seem to play a similar role. But what is the airflow? I know the cold air intake at the front bottom passes first through the heat exchanger, cooling it and condensing moisture from air exiting the drum. But where does the "dry" air go? Back into the drum? Exhaust into the room?

Seems like if it's back to the drum, then it's important to feed the intake the coolest air available, to maximize temperature drop, therefore condensation, thereby reducing drying time and energy use. But if this air then gets heated and passed into the drum, exceedingly cold intake would require more energy to heat, raising energy use.

I'd appreciate some insight. BTW, this is not a heat-pump dryer but a current-production condenser model. Despite years of hoopla and general availability in other parts of the world, the US has not yet jumped onto this bandwagon.