Every load of laundry sends lint through the dryer and out the vent. Most of it is caught by the lint screen, but some always gets past. Over months it builds up inside the duct, where it slows airflow, makes the dryer run hotter and longer, and gives a fire something to burn. Fire safety agencies consistently name failure to clean dryers as a key factor in home dryer fires.
Philadelphia homes add their own twist. In older rowhouses, the dryer is usually in the basement, and the vent may run along the joists to a window insert or out the back wall. In new construction, the dryer is often in a second-floor closet with a long run to an exterior wall or the roof. Long, hidden vents are exactly where lint collects.
Warning signs to act on now
- A normal load now needs two cycles.
- The dryer cabinet or clothes feel unusually hot.
- A burning smell, or a musty smell when the dryer runs.
- Little or no airflow at the outside hood while the dryer is on.
- Lint collecting behind the dryer or around the outside vent.
If you notice a burning smell, stop the dryer, unplug it if you can do so safely, and don't use it until the cause is found.
The vent checklist, inside to outside
| Step | Where | What to do | Done right |
|---|---|---|---|
| 1 | Lint screen | Clean before or after every load; wash it with soapy water now and then | Water runs through the screen freely; no waxy film from dryer sheets |
| 2 | Screen housing | Use a narrow vacuum attachment in the slot the screen sits in | No packed lint in the slot |
| 3 | Transition duct | Pull the dryer out and inspect the connector behind it | Rigid or semi-rigid metal, not crushed, no vinyl or foil accordion duct |
| 4 | Connections | Check how duct sections are joined | Foil tape or clamps, not screws that poke into the duct and snag lint |
| 5 | Run length and bends | Follow the duct from the dryer to the outside | As short and straight as practical, within the dryer manual's limits |
| 6 | Hidden sections | Look along basement joists or ask about runs inside walls and ceilings | No sagging dips where lint and moisture collect |
| 7 | Outside hood | Run the dryer and look at the hood | Flap opens fully and closes when off; no screen over it |
| 8 | Hood surroundings | Check outside after storms and in spring | No snow drift, leaves or bird nests blocking it |
| 9 | Area around the dryer | Look at what's stored nearby | No laundry piles, boxes, cleaning products or paint near the dryer |
| 10 | Full duct cleaning | Brush kit or professional cleaning | Done regularly, more often for big households or long runs |
Rowhouse basement vents
Basement window vents are common and they work, but they need care. The window insert should be sealed so exhaust doesn't leak back into the basement, and the outside opening often sits close to the ground, in a light well or behind a rear fence. In winter, a snow drift can block it; in fall, leaves pile up. After a big storm, go outside and check that it's clear.
Some basement dryers vent through a long horizontal run to the back of the house. Every extra foot and bend slows the air and gives lint a place to settle. If your run is long, check the dryer manual for the maximum length and consider a professional cleaning more often.
Second-floor closet dryers
Newer homes in neighborhoods like Fishtown, Northern Liberties, Graduate Hospital and Brewerytown often put the dryer in an upstairs closet. Those vents may run through ceilings to an exterior wall or roof, which means you can't see most of the duct. Watch drying times closely: a dryer that slowly takes longer is often the first sign. Roof vents can also collect lint at the cap; don't climb onto a roof to check it yourself unless it's safe, such as from an accessible roof deck.
Gas dryers need one more check
Many Philadelphia homes have gas dryers. A blocked vent on a gas dryer doesn't just slow drying; it can push combustion gases, including carbon monoxide, back into the house. Keep a working CO alarm on the level with the dryer and near sleeping areas, and see the carbon monoxide checklist for more. If you smell gas, leave the house and call PGW or 911 from outside.
Habits that help
- Don't run the dryer when you leave the house or go to bed.
- Don't dry items stained with oil, gasoline or cleaning solvents.
- Don't overload the drum; crowded loads take longer and run hotter.
- Replace any vinyl duct you find, even if it "seems fine."
Source
When to call: if the vent is clean and the dryer still overheats, runs without heat, or trips a breaker, the problem may be a thermostat, thermal fuse, heating element, gas valve or blower. Our dryer repair technicians can track it down. For a full look at your laundry area, see the laundry setup checklist.