What to Do When Your Heater Stops Working After a Storm

When a storm rolls through and knocks out the power, it is very common for the electricity to come back before the heat does. You turn the thermostat up, expect warm air from the vents, and nothing happens. Have you ever had the power come back on but the heat never follows? You are not alone.

At Fox Family Heating and Air Conditioning, we see this problem every fall and winter after thunderstorms and wind events in the Sacramento Valley. Brief outages, voltage drops, and lightning strikes can all affect modern furnaces and heat pumps, especially the sensitive electronics inside the equipment.

Before you assume the worst, there are several safe checks you can try as a homeowner. This guide will explain why storms cause heater problems, which steps you can take yourself, and when it is time to call in a professional.

Safety note: If you see downed power lines, smell gas, notice heavy smoke, or hear arcing or buzzing from your electrical panel, step away and contact your utility company or emergency services before you touch the heating equipment.

Why Furnaces Stop After Storms

Storms can affect a heating system in a few different ways. Some issues are simple, while others require a trained technician.

The first concern is the power supply. Your furnace or air handler typically runs on 120 volts, and a heat pump outdoor unit usually runs on 240 volts. During a thunderstorm, the utility can experience rapid changes in voltage when power is lost and restored. That change can trip a breaker, blow a fuse, or interrupt the low-voltage power that feeds your thermostat.

Lightning strikes can also create voltage spikes. Those surges travel along the wiring in your home and can damage electronic components inside the equipment. The control board, transformer, relays, or safety switches may show visible signs of damage, or they may simply stop working without an obvious mark.

Finally, some systems go into a protective lockout after repeated failed start attempts or a power interruption. The equipment is trying to protect the motors and electronics, so it will not start again until you reset it or enough time has passed.

The good news is that many post-storm heating issues come down to power and settings that you can check from outside the furnace cabinet.

Quick Checks to Try First

Before you open panels or touch wiring, start with these basic checks. They often get a heater running again in just a few minutes.

1. Confirm the thermostat is calling for heat

• Look at the thermostat display. Is it completely blank, flickering, or showing an error message?
• Make sure the system is set to Heat, not Cool or Off.
• Raise the set temperature at least 3 to 5 degrees above the current room temperature so the thermostat clearly calls for heat.
• If your thermostat uses batteries, replace them with fresh ones. A storm-related power event can drain weak batteries quickly.
• If the thermostat is blank even with new batteries, that can be a sign that the furnace is not providing the 24 volts needed to power it, which usually requires a technician to diagnose.

2. Check the furnace or air handler power switch

Most furnaces and air handlers have a service switch nearby that looks like a regular light switch. It may be on the side of the unit, on the ceiling above it, or on a wall close by.

• Make sure this switch is in the On
• If you are in an attic or garage, double-check that no one bumped the switch while moving boxes or tools around during the storm.

If the switch is off and you turn it on, give the system a few minutes to respond. You may hear the blower or inducer motor start before warm air reaches the registers.

3. Check the main electrical panel

Next, go to your main electrical panel and look for the breakers labeled Furnace, Air Handler, or Heat Pump.

1. Verify that the rest of the house has power. Do lights and outlets in other rooms work normally?
2. Look closely at the breaker handle for the heating equipment. A tripped breaker may sit between On and Off.
3. If the breaker appears tripped, push it firmly to the Off position first, then back to On.
4. Return to the furnace or air handler and listen for signs of life. It can take a few minutes for the system to start a normal heating cycle.

If the breaker immediately trips again, do not keep resetting it. This usually means there is a short or damaged component that needs professional attention.

4. Inspect the equipment area for obvious damage

Without opening any panels, take a quick look at the heater, nearby outlets, and cords.

• Do you see soot, scorch marks, or melted plastic on the furnace cabinet, plug, or outlet?
• Does anything smell like burned wiring or hot electronics?
• Is water from the storm pooling around the base of the furnace or air handler?

If you see any of these red flags, stop troubleshooting and call a licensed HVAC contractor or electrician. Continuing to reset power in this situation can be unsafe.

The Reset Procedure

If the thermostat is calling for heat, the breakers are on, and you do not see obvious damage, a simple reset is often the next best step. Many furnaces and heat pumps recover after a full power cycle.

Follow these steps:

1. Set the thermostat to Off or turn the temperature down so it is not calling for heat.
2. Turn the furnace or air handler power switch to Off. If your system plugs into an outlet, you can unplug it instead.
3. Wait at least 30 seconds. This allows the internal control board to fully power down.
4. While you wait, glance at the cord and outlet again. If you notice soot or melted plastic, stop and call a professional.
5. Restore power by turning the switch back to On or plugging the cord back in.
6. Turn the thermostat back to Heat and set the temperature above room temperature so it calls for heat.
7. Wait up to five minutes. Some equipment has built-in time delays after a power interruption or lockout.

During this time, you may hear the inducer fan start, the burners ignite on a gas furnace, and finally, the main blower come on. For a heat pump, you may hear the outdoor unit and indoor blower start in sequence.

If the system still does not start after a careful reset, it is time to think about possible internal damage.

Control Board Damage After a Power Surge

Modern heaters rely on electronic control boards to coordinate safeties, blowers, ignition, and communication with the thermostat. Power surges from lightning or utility switching can damage these boards or the small transformer that provides 24-volt power.

Here are some signs that the control board or related components may be damaged:

• The thermostat is blank even though other lights and outlets in the home are working.
• There is no small status light visible through the furnace sight glass, or the light never comes on after power is restored.
• The furnace tries to start but quickly shuts down and repeats, or it shows an error code every time it attempts to run.

Many furnaces have a small clear window on the lower panel where you can see red or yellow LEDs flashing. If you can safely see that window without removing panels, count the flashes and write down the pattern. For example, you might see three short flashes followed by two long flashes. Your HVAC technician can use that information to narrow down the issue quickly.

You should not remove furnace panels or reach into the wiring unless you are trained and comfortable working around electricity and gas. Control board replacement, transformer testing, and detailed electrical diagnosis are best handled by a professional.

Surge Protection for Your Furnace and Heat Pump

Once your heater is running again, it is worth thinking about how to protect it from the next storm. The electronics inside furnaces, air handlers, and heat pumps do a lot of work to keep you comfortable, and they are often the most expensive parts to replace after a power surge.

Our technicians often recommend:

• Whole home surge protection: Installed at your main electrical panel, this helps protect all the sensitive devices in your home, from HVAC equipment to refrigerators and electronics.
• HVAC-specific surge protectors: These devices are mounted at the outdoor heat pump or near the indoor furnace to absorb spikes before they reach the control board.

Here in the Sacramento Valley, we deal with more than just thunderstorms. Summer heat waves, heavy electrical demand on SMUD or PG&E systems, and wind events can all contribute to brief outages and voltage swings. Adding surge protection is a relatively small investment compared to replacing a furnace control board or heat pump defrost board after every big storm.

If your home has already experienced one storm-related HVAC failure, talk with your technician about whether surge protection makes sense for your system.

When to Call for Help

Some problems are safe for a homeowner to troubleshoot. Others should be left to a qualified technician who has the right tools and training. Not sure whether it is safe to keep troubleshooting? Use this list as a guide.

Call Fox Family Heating and Air Conditioning if:

• The breaker for the furnace or heat pump will not reset or trip again after you turn it on.
• You see or smell burning, soot, or melted plastic on the furnace, outlet, plug, or nearby wiring.
• The thermostat stays blank after you replace the batteries and reset the power.
• The heater will not start even after you have checked the thermostat, switch, breaker, and completed a reset.
• You see unusual error codes flashing inside the furnace cabinet or on the thermostat display.
• You simply are not comfortable working around electrical panels, gas lines, or internal furnace components.

When our technicians arrive, they will:

• Verify that your home has proper voltage from the panel to the heater.
• Inspect wiring, plugs, and outlets for storm-related damage.
• Test the transformer, control board, and safety circuits.
• Confirm that motors, relays, and ignition components are operating safely.
• Check that flues and drain lines are clear and that there is no water damage around the equipment.

If repairs are needed, we will explain your options clearly, give you straightforward pricing, and help you decide whether repair or replacement is the better choice for your home and budget.

For many homeowners in Rancho Cordova and Sacramento, we can provide same-day service so you are not without heat during those chilly November and December evenings.

Conclusion

Storms and power outages can be hard on your heating system, but a silent furnace after the power comes back on does not always mean a major failure. By checking your thermostat, switches, and breakers, then performing a careful reset, you might restore heat quickly and safely.

When those steps do not solve the problem, or when you see signs of damage, it is important to bring in a professional. Our team can diagnose surge-related problems, repair or replace damaged control boards, and recommend surge protection so your system is better prepared for the next storm that passes through the Sacramento Valley.

Fox Family Heating and Air Conditioning serves Rancho Cordova, Sacramento, and Northern California. If you need help getting your heater running again after a storm, give us a call!