Radiators help to warm up the rooms of your prison if the weather/temperature system is activated. In order to do so, they need to be connected to a Water Boiler with Hot Water Pipes that cannot be too long.
Radiator generates heat up to 20°C (68°F), excluding the tile on which radiator is placed which has 21°C (69°F). Every two tiles away from the radiator, temperature drops by 1. It drops even more in the areas with windows and doorways to outside which allow cold air to get in, making radiators less effective. (See Temperature for more info).
Utility preview with hot water pipes providing hot water for shower heads and radiators.