Dryer Heating but Not Drying: Causes and Fixes

When your dryer heating but not drying is the problem, the drum feels warm — sometimes downright hot — yet clothes come out damp after a full cycle. A dryer heating but not drying almost always points to one thing: hot air is getting in, but moisture is not getting out. Fix the airflow or the sensor and the drying comes back.

This is a different failure from “no heat at all,” which usually means a blown heating element, thermal fuse, or thermostat. Here the heat is fine. The trouble is airflow, venting, or the sensor that tells the machine when clothes are dry. Work through the causes below in order — cheapest and most common first.

Why Heat Without Drying Happens

Drying is not just heat; it is heat plus airflow carrying evaporated water out of the drum. Warm air picks up moisture from wet clothes, then must exit through the lint screen, the duct, and the exterior vent. Block that path and the humid air just recirculates. Clothes stay damp, the drum runs hot, and cycle times balloon. So the first suspects are anything that restricts airflow.

Cause 1: Clogged Lint Screen

The simplest fix and the one people skip. A lint screen that looks clear can still be choked by a film of fabric-softener and dryer-sheet residue that blocks air at the microscopic level.

• Pull the screen and hold it up to a light — a clean screen passes light freely.
• Run water through it. If water pools on top instead of pouring through, the mesh is glazed.
• Scrub both sides with warm water, a little dish soap, and a soft brush, then dry it fully before reinstalling.

Do this monthly. A clogged screen alone can cut drying performance in half.

Cause 2: Blocked or Clogged Vent Duct

This is the number-one cause of a dryer heating but not drying — and the most dangerous. Lint that gets past the screen packs into the duct and the exterior vent, choking airflow to a trickle. Beyond ruining drying, the trapped lint is the leading cause of the roughly 2,900 dryer fires U.S. firefighters respond to each year.

Diagnose it:

1. Run the dryer on a timed cycle and go outside to the exterior vent hood. Put your hand near it — you should feel a strong, warm gust. Weak or no airflow confirms a clog.
2. Check that the vent flap or shuttle is opening. A flap frozen shut in winter or jammed with lint blocks everything.
3. Disconnect the duct from the back of the dryer and inspect it. A visible lint mat means it is time to clean.

Clear it with a dryer-vent brush kit — a flexible rod that runs the full length of the duct. Vacuum the debris, and while you are back there, replace any plastic or foil “slinky” duct with rigid or semi-rigid metal. Foil flex sags, traps lint, and is a fire risk; metal keeps a smooth path that self-clears.

Cause 3: Crushed or Kinked Transition Duct

If you recently pushed the dryer back against the wall, you may have crushed the flexible duct behind it. A sharp kink strangles airflow just as badly as a clog. Pull the dryer out and check that the transition duct behind it makes a gentle curve, not a hard fold. Swap a crushed foil duct for a semi-rigid metal one or an offset “periscope” elbow that lets the dryer sit close to the wall without pinching the pipe. Never secure duct joints with screws that poke inside — the tips snag lint and start a new clog.

Cause 4: Faulty Moisture Sensor

Most dryers built since the 2000s use automatic cycles governed by a moisture sensor — two metal strips inside the drum that read electrical conductivity across the tumbling clothes. Wet clothes conduct; dry clothes do not. When the sensor reads “dry,” the cycle ends. If the sensor is fooled, the machine shuts off while clothes are still damp even though heat and airflow are fine.

What throws off a moisture sensor:

• Dryer-sheet and fabric-softener film coating the metal bars, insulating them so they always read “dry.” This is the most common sensor fault.
• Physical damage or corrosion on the strips.
• A loose wire or failing control-board connection feeding the sensor.

Fix the easy version first: locate the two curved metal bars inside the drum (usually near the lint-screen opening or on the front baffle) and wipe them with a cloth dampened in rubbing alcohol. That strips the softener film and restores an accurate reading on most machines.

Test it: dampen a small towel, run an automatic (sensor) cycle, and see if it stops early. Then run the same towel on a timed cycle. If the timed cycle dries it but the sensor cycle quits early, the sensor or its wiring is the culprit. A replacement sensor runs $15-$40 in parts; the wiring harness or control board is a pricier repair, typically $150-$300 with labor.

Cause 5: Overloading

Cramming the drum defeats airflow from the inside. Clothes need room to tumble so warm air can circulate through the load. If you routinely fill the drum more than three-quarters full, split the load. Bulky items — comforters, mattress pads, thick towels — trap water in their cores and need extra time or a dedicated smaller load. An overloaded drum also throws off the moisture sensor, which only reads the clothes that brush past its bars.

Cause 6: Low Voltage on an Electric Dryer

An electric dryer runs on a 240-volt circuit with two hot legs. If one leg fails — a tripped half of a double-pole breaker, a burned terminal, or a bad outlet — the dryer often still tumbles and the drum light works on the surviving 120-volt leg, but the heating element runs weak or intermittently. You feel some warmth but never enough to dry. If you have ruled out airflow and the sensor, have an electrician or technician check for a proper 240 volts at the outlet. This is not a DIY electrical test unless you are comfortable and equipped for live 240-volt measurement.

Cause 7: Vent Termination Problems Outside

Sometimes the duct inside is clean but the exterior vent is the choke point. Walk outside while the dryer runs and inspect the hood itself:

• A flap frozen or painted shut — the exhaust has nowhere to go. Free it or replace the hood.
• A screen or mesh someone added to keep pests out — it clogs with lint in weeks and must come off. Use a screen-free damper hood instead.
• A bird or rodent nest built inside the hood over a season of disuse. Clear it and add a floating-shuttle cap that seals when idle.
• Snow or ice banked over a low exterior vent in winter. Raise the termination or clear the drift.

The hood is easy to overlook because it is out of sight, yet a blocked termination stalls the whole system no matter how clean the interior duct is.

A Quick Diagnostic Order

Run through the checks fastest-and-most-likely first:

1. Clean the lint screen and test it with water.
2. Feel the exterior vent for strong airflow while running.
3. Check behind the dryer for a crushed or clogged duct.
4. Wipe the moisture-sensor bars with alcohol.
5. Reduce the load size and retest.
6. If heat is weak on an electric unit, check for a lost 240-volt leg.

Nine times out of ten the answer is somewhere in the airflow path — a glazed screen, a packed vent, or a kinked duct. The moisture sensor is the usual runner-up. Both are cheap fixes you can often handle in an afternoon.

The Bottom Line

A dryer heating but not drying is telling you that moisture cannot escape. Start with the lint screen and the vent duct, because a clogged vent is both the most common cause and a real fire hazard — always run rigid or semi-rigid metal duct with no interior screws. If airflow checks out, clean the moisture sensor, right-size your loads, and finally verify full voltage on electric models. Work the list in order and you will have your clothes drying in a single cycle again.