Why does my dryer run but not heat?

A dryer can tumble on a small motor circuit while the heat source is dead. On electric dryers the most common cause is a blown thermal fuse or failed heating element, often triggered by a clogged vent; a tripped half of the 240V breaker will also spin the drum with no heat. On gas dryers it is usually a failed igniter or gas valve coils. A blocked vent is behind a large share of all no-heat calls.

Can a clogged dryer vent stop the heat?

Yes. A blocked vent traps hot air and makes the dryer overheat, which trips the thermal fuse or high-limit thermostat as a safety cutoff — after that the dryer runs cold. Clearing the vent is essential, but the tripped fuse usually still needs replacing. A clogged vent is also the leading cause of dryer fires, so it should not be ignored.

Is it safe to keep using a dryer that won't heat?

Running it a few minutes to test is fine, but do not keep cycling a dryer that overheats, smells hot, or smells like gas. A gas smell means stop immediately, shut off the dryer, and call for service. Repeated overheating points to a venting or thermostat fault that is a fire risk.

How much of a dryer no-heat repair can I do myself?

You can safely clean the lint filter and vent, check that both household breakers are on, and make sure the dryer is not in a low-heat or air-fluff setting. Replacing a heating element, igniter, gas valve coils, or thermal fuse involves the 240V circuit or the gas system and is best left to a technician.

Alpha & Omega HVAC Appliance Repair · Orange County, CA · Updated July 2026

Dryer Not Heating? Why It Tumbles but Stays Cold

A dryer that runs but leaves your clothes damp is one of the most common calls we get in Orange County — and one of the most misunderstood. The drum spinning tells you the motor is fine; it says nothing about the heat source. Here is how we think through a no-heat dryer, what you can safely check, and where the line is between a DIY fix and a service call. Related: our dryer repair service.

First: Gas or Electric? It Changes Everything

Electric dryers make heat with a heating element on a 240-volt circuit. Gas dryers make heat by igniting gas with an igniter and gas valve coils, using 120 volts. The failure list is different for each, so knowing which you have saves time. If you are not sure, a gas dryer has a gas shutoff valve and a flexible gas line behind it.

The 240-Volt Breaker Trap (Electric Dryers)

An electric dryer uses two 120-volt legs. The motor and drum light run on one leg; the heating element needs both. If one leg trips — which a single breaker switch or a partially tripped double breaker can cause — the drum spins normally but there is no heat at all. Before anything else, fully switch the dryer's double breaker off and back on. This alone fixes a surprising number of “dead heat” dryers.

Check the Vent — the Hidden Culprit

A clogged vent is behind a huge share of no-heat calls. Trapped heat makes the dryer overheat, and a safety device (the thermal fuse or high-limit thermostat) cuts the heat to prevent a fire. Signs of a restricted vent: clothes take two or three cycles to dry, the dryer top gets very hot, or the outside vent flap barely moves. Clean the lint filter every load and clear the full vent run to the outside. A blocked vent is also the number-one cause of dryer fires, so this step protects more than your laundry.

Electric No-Heat: What Fails

Thermal fuse. A one-time safety fuse that blows after an overheat (usually from a clogged vent). Once blown, the dryer runs cold until it is replaced — and the vent must be cleared too, or the new fuse will blow again.
Heating element. The coil that makes the heat. Elements burn out or short over time; a broken element means no heat even with perfect airflow.
Thermostats / thermal cutoff. Cycling and high-limit thermostats regulate temperature; a failed one can leave the dryer cold or, worse, running too hot.

Gas No-Heat: What Fails

Igniter. The most common gas-dryer failure. A weak or cracked igniter can't get hot enough to light the gas, so the burner never fires.
Gas valve coils. These open the gas valve. When they fail, the igniter may glow but no gas is released — so it glows, then cools, with no flame.
Flame sensor and thermal fuse. As with electric, a blown thermal fuse from a clogged vent will stop the heat.
Gas supply. Make sure the gas shutoff valve behind the dryer is fully open.

Safety: When to Stop

Testing for a couple of minutes is fine. Stop and call if you smell gas (shut the dryer off and ventilate first), if the cabinet gets alarmingly hot, or if you get a burning smell beyond normal lint. Overheating is a fire hazard, not just an inconvenience.

What We Do When We Arrive

We confirm gas vs. electric, test the breaker legs on electric units, and check airflow through the vent. Then we test the heat circuit component by component — element or igniter, gas valve coils, thermostats and the thermal fuse — with a meter, so we replace the part that actually failed and clear the vent condition that caused it. That last step is what keeps the repair from coming back. See also our appliance maintenance checklist and, if the dryer is older, repair or replace?