The answer to 'when to service emergency HVAC service' is to call for professional HVAC service any time your heating or cooling system is not functioning properly or exhibiting signs of failure. This includes issues like a complete system breakdown, strange noises or odors, or if the system is not maintaining the desired temperature in your home.
It's important to address HVAC emergencies promptly to prevent further damage to the system and ensure your home remains comfortable and safe. Professional HVAC technicians can quickly diagnose the problem and provide the necessary repairs or maintenance to get your system back up and running.