Evaporator tray (100) for a sauna heater has one or more elongate plate members (102) extending across a support member (104). Support member (104) has at least two sides. In use, plate members (102) support rocks (not shown). Plate members (102) have a generally concave or hollow cross-section with a hollow face (106) upturned, which means they can collect unevaporated water, thereby protecting the sauna heater. The generally concave shape may be “V”-shaped, “U”-shaped, arcuate or concave, or any shape suitable for retaining water.