Furnace Heating Element Not Working: Causes, Diagnosis, and Fixes

The following guide explains why a furnace heating element not working can occur, how to diagnose the issue safely, and what steps homeowners can take or when to call a professional. It focuses on electric furnaces and furnaces with heat strips, common symptoms, troubleshooting tips, replacement guidance, and safety considerations.

Symptom	Likely Cause	Quick Action
No Heat	Tripped breaker, failed heating element, thermostat issue	Check breaker, thermostat settings, call technician
Intermittent Heat	Loose connection, failing relay, overheating cutout	Inspect wiring and contactor, replace faulty parts
Shorted Element	Burned-out filament or internal short	Replace heating element or heat strip
Blower Runs But No Heat	Heating element not energizing	Test for voltage at elements, check fuses

How Electric Furnace Heating Elements Work

Electric furnaces use heating elements or heat strips—metal coils that convert electrical energy into heat through resistance. When the thermostat calls for heat, a relay or contactor supplies voltage to the elements. The blower circulates air across the hot elements, sending warm air through the ductwork.

Key Components include heating elements/heat strips, contactor/relay, high-limit cutoff switch, fuses or breakers, thermostat, and blower motor. Failure of any component can make the furnace heating element not working.

Common Causes When A Furnace Heating Element Is Not Working

Tripped Circuit Breaker Or Blown Fuse

Electric furnaces draw significant current. A tripped breaker or blown fuse is a frequent, simple cause of no heat. Repeated tripping often points to deeper issues like shorted elements or a failing component causing overcurrent.

Failed Heating Element Or Heat Strip

Heating elements burn out over time from repeated heating cycles or manufacturing defects. A failed element will not produce heat and may show visible damage or melting. In multi-element units, one failed strip can reduce output; a fully failed strip produces no heat.

Bad Contactor Or Relay

The contactor or relay delivers power to elements. When it fails, the control signal is present but voltage does not reach the elements. Symptoms include the furnace trying to start (blowers running) without elements energizing.

Thermostat Or Control Board Fault

Faulty thermostats or control boards can fail to call for heat or send incorrect signals. This can mimic an element failure. Checking for a control call and verifying voltage at the element terminals helps isolate the problem.

High-Limit Switch Or Safety Cutoff Tripped

High-limit switches prevent overheating. If a switch trips due to airflow restriction or a faulty sensor, it interrupts power to the elements. Resettable cutoffs or fault codes on modern controls may provide diagnostics clues.

Loose Or Corroded Wiring And Connections

Loose terminals or corroded connections increase resistance and prevent elements from receiving full voltage. These issues can cause intermittent heating or arcing, which is a fire risk and requires prompt repair.

Safety First: Precautions Before Troubleshooting

Always shut off power at the furnace disconnect and the breaker before inspecting electrical components. Use a non-contact voltage tester to confirm power is off. If the homeowner lacks experience with high-voltage systems, hire a licensed HVAC technician or electrician.

Step-By-Step Troubleshooting Guide

1. Verify Thermostat Calls For Heat

Set the thermostat to a temperature above room temperature and observe whether the control board registers a heat call. On many models, a status light or code will indicate a call for heat. If no call is present, check thermostat wiring and batteries.

2. Check Breakers And Fuses

Inspect the electrical panel for tripped breakers or blown fuses dedicated to the furnace. Reset tripped breakers once. If a breaker trips again quickly, it signals a short or overload and requires professional diagnosis.

3. Inspect The Contactor Or Relay

With power on and a heat call active, carefully observe the contactor to see if it pulls in. A stuck or non-operating contactor suggests replacement. Some contactors include visible pitted contacts that indicate wear.

4. Test For Voltage At Heating Elements

Using a multimeter set to the correct AC voltage range, measure voltage at the element terminals during a heat call. No voltage indicates a control or wiring issue; correct voltage with no heat indicates a failed element.

5. Check Element Continuity

With power off, measure resistance across each element. A reading of infinite resistance means an open (failed) element. Compare readings to manufacturer specifications; significant deviations suggest degradation.

6. Examine For Visible Damage Or Burn Marks

Inspect heating elements and surrounding insulation for discoloration, melting, or burn marks. Damaged elements must be replaced and surrounding wiring checked for heat damage.

Repair Options And When To Replace Parts

Replacing A Heating Element Or Heat Strip

Replacement is straightforward for accessible elements—disconnect power, remove furnace access panels, unscrew terminals, and replace the faulty strip with the exact model specified by the manufacturer. Match physical dimensions, voltage, and amperage ratings.

Replacing Contactors, Relays, Or Control Boards

Contactors and relays are common replacements. Choose parts that match coil voltage and contact ratings. Control boards require correct part numbers and often professional installation due to programming or safety interlocks.

Repairing Wiring And Connections

Tighten loose terminals, replace corroded connectors, and use proper wire gauges. Damaged wires should be replaced using appropriate insulation and strain relief. Ensure all connections are secure to prevent arcing and overheating.

Addressing Underlying Causes

If elements fail repeatedly, investigate root causes such as poor airflow, undersized ductwork, malfunctioning blower, or incorrect voltage supply. Fixing the cause prevents repeated part failures and improves efficiency.

Cost Considerations And Typical Prices

Costs vary by part and labor. Heating elements or heat strips typically range from $50 to $300 depending on model and size. Contactor or relay replacement can range from $75 to $300. Control board replacement and labor may cost $300 to $1,000 or more.

Note: Prices vary by region and complexity. Always obtain multiple quotes and verify technician licensing and warranty coverage.

When To Call A Professional

Call a licensed HVAC technician or electrician if the problem involves high-voltage testing beyond homeowner comfort, repeated breaker trips, control board replacement, or when safety devices require diagnosis. Professionals can also ensure proper replacement parts and restore safe operation.

Preventive Maintenance To Keep Heating Elements Working

• Schedule annual HVAC inspections to detect wear early and verify electrical connections.
• Replace or clean air filters regularly to maintain proper airflow and prevent overheating.
• Keep vents and returns unobstructed and ensure the blower motor operates correctly.
• Verify correct line voltage to the unit; sustained over- or under-voltage shortens element life.
• Address any unusual smells, noise, or frequent cycling immediately to prevent damage.

Diagnostic Checklist For Homeowners

1. Confirm thermostat call for heat and correct mode.
2. Check furnace disconnect and breaker for power.
3. Listen for contactor pull-in or smell of burnt insulation.
4. Inspect visible elements for damage or discoloration.
5. Test continuity of elements with power off (or hire a pro).
6. Measure voltage at element terminals during heat call (pro recommended).

Frequently Asked Questions

Can A Blower Running Without Heat Mean The Element Is Bad?

Yes. If the blower runs but the heating element not working, the control may be energizing the fan but not powering the elements due to a failed contactor, blown fuse, or open element.

How Long Do Heating Elements Last?

Element lifespan depends on use, voltage stability, and airflow conditions. Typical life ranges from 5 to 15 years. Regular maintenance and stable power extend life expectancy.

Is It Safe To Temporarily Run A Furnace With One Element Out?

Some multi-element units can operate with one strip out, but this reduces heat output and can cause imbalance in system operation. It is safer to replace failed elements promptly.

Can A Homeowner Replace A Heating Element?

Yes for those comfortable with basic electrical safety and following manufacturer instructions. However, because of high voltage and safety concerns, many homeowners prefer a licensed technician for diagnosis and replacement.

Resources And Tools For Troubleshooting

Useful tools include a multimeter capable of AC/DC voltage and resistance, non-contact voltage tester, insulated screwdrivers, socket set, and manufacturer service manual or wiring diagram. Always reference the furnace datasheet for specifications.

Online resources such as manufacturer support pages and professional HVAC forums provide model-specific guidance and part numbers, while local codes and safety regulations should guide repairs.

Key Takeaways

When a furnace heating element not working occurs, the issue may be a simple breaker trip or a complex electrical failure. Systematic troubleshooting—checking thermostat calls, breakers, contactors, voltage, and element continuity—helps identify the root cause. Prioritize safety and consult a licensed professional for high-voltage work, repeated failures, or control board replacements.