This is the 5727th most frequent French word.
chauffé
Heated.
In this sentence, "chauffée" is used in the past participle form to indicate the state of the water being heated.
L'eau a été chauffée pour préparer du thé.
The water was heated to prepare tea.
Here, "chauffé" is implied as part of the heating system, though "chauffage" specifically refers to the heating appliance.
Le chauffage n'est pas en marche, alors il fait froid ici.
The heating is not on, so it is cold here.
The usage of "chauffée" here describes the room as being in a warmed state due to the radiator.