Why does your washer dryer combination dry slowly?

Warm, humid air results in condense on a cold surface. This happens when you take a bottle of water from the fridge on a hot summer's day. The little droplets form almost instantly. This doesn't happen with a warm battle. The same goes for laundry. The moisture from the clothing condenses on the cold part of the washer dryer combination. That's the outer tub that's around the drum. This is cooled with water.

With a separate dryer, the hot humid air condenses on the extremely cold part of the condenser. A washer dryer combination doesn't have a condenser, so it also doesn't have a cold side. With a washer-dryer combination, the humid air condenses on the cooled wall of the outer tub that's around the drum. This can never get as cold as a condenser. Because the colder tub doesn't attract much moisture, it takes longer before all the moisture is gone. This way, it takes longer for the dryer cycle to finish than with a separate dryer.