One of the first signs of HVAC problems is from the energy bill. A sudden spike in the bill means that the system is working much harder than it has to—an indicator that something needs to be repaired. This is true even when the system is displaying any symptoms.

The energy bill spike is a very reliable indicator, but not a very convenient one.

Even so, it’s much better to find an energy bill spike than to have your system break down completely. Of course, it’s only useful if you call for repairs as soon as possible!

One possible reason for airflow issues with your furnace could be due to the furnace overheating. Overheating will often cause the limiting switch to trigger, which will turn the pilot off. This is meant as a safeguard against overheating, so you’ll have to find the root cause of the issue.

Overheating issues can usually be solved with some quick maintenance. If you know for a fact that your furnace hasn’t been maintained in a long time, it could have created one of these problems:

Clogged Air Filter: The air filter protects the furnace from being contaminated with dust and dirt. The air filter is essential, but it comes with the burden of needing to be replaced multiple times a year. If you haven’t had the filter changed in at least a year, there’s a strong indication this can be the cause of your problem.

Broken Blower: The blower is the fan that sends hot air through the ducts and into the home. If the fan motor has burnt out, or if dust or debris is obstructing the fan, it can cause the fan to stop working. The hot air that builds up would lead to the unit overheating.

The furnace might have trouble operating at all. This could be due to the pilot light or electronic igniter failing to operate. There are a few things you can do to see if this is the problem, but we generally don’t advise trying to fix any issues related to these components. Making repairs to anything involving the gas line or electrical parts is highly dangerous for an amateur.