The answer to 'water heater blowing hot air' is that this is likely caused by a faulty temperature and pressure (T&P) relief valve on the water heater. The T&P valve is designed to release excess pressure and prevent the tank from exploding, but if it's malfunctioning, it can cause hot air to be blown out instead.
Other possible causes include a thermostat issue, sediment buildup in the tank, or a problem with the heating element. If the water heater is blowing hot air, it's important to address the issue quickly to prevent further damage and potential safety hazards.