If your furnace is not producing enough heat to keep your home warm and comfortable, it's a clear sign that something is wrong. This could be due to a variety of issues, including a malfunctioning thermostat, clogged filters, or a failing heating element.

Unusual or loud noises coming from your furnace, such as banging, screeching, or popping sounds, can be indicative of mechanical problems. These noises may be caused by loose or damaged components, and it's important to address them promptly to prevent further damage.

If you notice a sudden and significant increase in your energy bills without a corresponding increase in usage, it could be a sign that your furnace is not operating efficiently. This may be due to issues like dirty or clogged filters, a malfunctioning blower, or other efficiency-related problems.

If your furnace is cycling on and off more frequently than usual, it can be a sign of various issues, including a faulty thermostat, a clogged filter, or improper airflow. This not only affects your comfort but can also lead to premature wear and tear on the furnace.