I have noticed many times that whenever I enter into the bathroom just after someone else bathed the temperature inside it would be high.
Is it that the body heat comes out when we pour a lot of water on our body? I asked many people this question but no one has the answer.
Note (from a comment) that this is in a warm climate where the bathwater is heated in the afternoons by sunlight on the storage tank, but not in the mornings; the heating of the bathroom is observed in either case. It's not a simple question of passing heated water through the bathroom.
Best Answer
If the water isn't heated, the only effect I can see is that the humidity is higher. If the ambient temperature is high, this will feel hotter. Have you measured the temperature,or are you relying on your sensation?