What is the safest heater to leave on overnight?

The safest heater to leave on overnight would be an electric heater with overheat protection and an automatic shut-off switch if it tips over. These features ensure that the heater will not overheat or cause any accidents while you sleep. It is important to read and follow the manufacturer's instructions for safe operation and maintenance. Using a heater with the proper safety features and responsible use can provide a comfortable and worry-free night's sleep.