Stop in for a cup of coffee

When heating air, the RH drops. Doesnt really matter how its heated.
Only exception would be an open flame since combustion results in some water formation. Open flame also heats the objects and people more than the air. win-win in that respect.
There's 'vapor pans' to add water to the heated air on a 'portable' warm air furnaces - mines from 1886. Having water heating on top of a plate stove goes back even further.