Furnace Not Working? 5 Things to Check Before Calling a Pro

If you’re asking yourself, “Why is my furnace not working?” — you’re not alone. It’s a common problem during Iowa’s cold season, and we know how stressful it is when your heat stops working. Before you call in a technician, there are a few quick checks you can make to possibly fix the issue yourself.

Whether you're waking up to a chilly house and the heat just isn’t kicking in, here are five things to look at when your furnace is not working.

1. Check the Thermostat Batteries

If your furnace isn’t working, your thermostat may be the culprit. When the batteries are dead or weak, your thermostat might not signal the furnace to turn on at all.

Tip: If you haven’t replaced the batteries in over a year, start there. Swapping them out is a quick fix that could get your heat running again.

2. Double-Check Your Thermostat Settings

Sometimes the issue is just a setting error. Ask yourself: “Did someone adjust the temperature or mode?”

Make sure your thermostat is:

• Set to “Heat”

• Programmed at a temperature higher than the current room temp (try 72°F to test)

• Not in a delay or hold mode

Still wondering “why is my furnace not working?” This step alone resolves the issue in many homes.

3. Make Sure Your Furnace Switch Is Turned On

Every furnace has a dedicated power switch that can sometimes be flipped off by mistake. This switch often looks like a light switch and is located on or near the side of your furnace.

If your furnace is not working at all, flip the switch off and back on to reset it. You’d be surprised how often this solves the issue.

4. Check Your Furnace Circuit Breaker

Head to your electrical panel and find the breaker labeled “furnace.” If it’s tripped (in the middle position), switch it to OFF, then back to ON.

This step is especially important if your furnace won’t turn on after a power outage or power surge.

5. Inspect and Replace the Furnace Filter

A dirty or clogged air filter is one of the most common reasons a furnace stops working. Reduced airflow can cause your system to overheat and shut down.

To avoid this:

• Check your filter monthly during the heating season

• Replace it if it looks dirty or clogged

• Make sure it’s properly installed facing the right direction

Regular filter changes can prevent future breakdowns and keep your HVAC system running efficiently.

Still Wondering Why Your Furnace Isn’t Working?

If you’ve checked all of the above and your furnace is still not working, it may be time to call in the pros. It could be a faulty ignitor, gas valve, or control board, all of which require a trained technician.

Bell Brothers is available 24/7 to help Des Moines homeowners with no-heat emergencies. Whether you’re dealing with inconsistent airflow, a furnace that won’t start, or strange sounds coming from your unit, we’re here to get your home warm again, fast.

Contact us online to schedule a furnace repair.