It’s one of the coldest days of the year and the only thing you want is to relax in the warmth and comfort of your home. Except when you enter, you’re hit with a blast of frigid air. What gives?

The last thing any homeowner wants on a cold day is a furnace that refuses to turn on. And because we never know what winter has in store for New Jersey homeowners like you, understanding some of the most common reasons your furnace may fail to start can help you avoid discomfort and unnecessary repair costs.

Here are some common reasons your furnace may not be working and what you can do about it.

Thermostat Issues

One of the most common reasons a furnace won’t turn on is a problem with the thermostat. If your thermostat is malfunctioning or the settings are incorrect, it may prevent your furnace from activating.

• Check that the thermostat is set to “Heat” mode and the temperature is higher than the current room temperature.
• Replace the batteries if needed.
• If you have a programmable one, make sure the programming hasn’t been accidentally changed.

Tripped Circuit Breaker

Furnaces require electricity to run, and if the power supply is interrupted, the furnace won’t turn on.

• Check your home’s electrical panel to see if the furnace’s circuit breaker has tripped. If it has, reset it by flipping it off and then on.
• If the breaker keeps tripping, there could be an electrical issue, and it’s best to call an electrician to inspect the problem.

Dirty or Clogged Air Filter

A clogged air filter can restrict airflow, causing your furnace to overheat and shut down as a safety precaution. It can also prevent the furnace from turning on at all if the airflow is severely restricted.

• Turn off the furnace and remove the air filter. Inspect it for dirt and debris.
• If the filter is dirty, replace it with a new one. It’s generally a good idea to replace air filters every 1-3 months, especially during the heating season.

Pilot Light or Ignition Problems

Furnaces that use a pilot light can experience issues if the pilot light goes out. Additionally, modern furnaces with electronic ignition systems may fail to ignite if the ignitor is faulty.

• If you have a pilot light, check to see if it’s out. If it is, follow the manufacturer’s instructions to relight it. Make sure the area around the pilot light is free from debris or dirt.
• For electronic ignition systems, listen for a clicking sound when you try to turn on the furnace. If you don’t hear it, the ignitor might be faulty and require replacement.

Gas Supply Issues

A furnace that runs on natural gas or propane may not turn on if there’s an issue with the gas supply. This could be due to a closed gas valve, a gas line issue, or a gas outage.

• If you suspect a gas leak or a larger gas supply issue, immediately shut off the furnace and contact your gas company from a safe location.
• In some cases, there could be a gas outage in your area, so check with your gas provider to confirm.

When to Call C&D

If basic troubleshooting doesn’t work, or if you’re not comfortable taking the DIY approach, contact C&D Cooling & Heating. We offer a complete package of heating services, including preventive maintenance, expert and timely repair, and, if needed, new system design and installation. Plus, we’re available for 24/7 emergency repair work, too.