It is July, the air conditioning is running, nobody has lit a fire since March, and the family room smells like a wet campfire. AM Chimney Sweep cleans, inspects and repairs chimneys in Edison, and summer fireplace odor is one of the most common reasons for a call outside the heating season. It has a clear explanation.
Two things have to be true
First, there has to be something in the chimney that smells. Second, air has to be traveling down the chimney into the house instead of up and out. Remove either one and the odor stops.
What smells
- Creosote and soot. The deposits left by wood fires have a sharp, smoky, asphalt-like odor that gets much stronger when the air is humid.
- Moisture. Rain entering an uncapped flue soaks the soot and the masonry. The smell turns musty, like a damp basement.
- Ash. A firebox left full of ash absorbs moisture all summer.
- Animals and debris. Nesting material, droppings, leaves or an animal that died in the flue produce a distinctly different, rotten smell.
Why the air comes down
In winter, a warm house pushes air up the chimney. In summer the situation reverses. The house is cooler than the outdoors, cool air is heavy and sinks, and it leaks out low in the building. Replacement air is drawn in from above, and the chimney is a direct route. Add a clothes dryer, bathroom fans and a kitchen exhaust, all of which pull air out of the house, and a tightly built home will draw steadily down the flue.
Edison’s housing and why it shows up here
Census Bureau estimates show that about a quarter of Edison’s homes were built in the 1980s, with roughly another third from the 1950s and 1960s. The 1980s houses and townhomes tend to be more tightly built, often with a factory-built fireplace whose metal chimney runs up inside a framed enclosure. When the metal cover at the top of that enclosure rusts, it lets water in, and a damp chase smells. The older masonry fireplaces more often have a worn throat damper that no longer closes properly, which leaves the path down the flue wide open.
Source: U.S. Census Bureau, American Community Survey 2020–2024 five-year estimates.
What actually fixes it
1. Take away the source
Have the chimney swept at the end of the burning season, not the start of the next one. Deposits removed in April cannot smell in July. Shovel out the ashes as well.
2. Keep water out
Fit a cap on a masonry flue. On a factory-built fireplace, replace a rusted chase cover. Have a cracked crown repaired.
3. Close the path
Make sure the damper closes and seals. If the original damper is warped or rusted, a top-sealing damper, which shuts the flue at the top with a gasket, is far more airtight. Glass doors on the fireplace help further.
4. Reduce the pull
If the smell is worst when the dryer or the kitchen fan is running, the house is short of incoming air. That is a question for your heating and cooling contractor, and it is worth raising.
What does not work
- Air fresheners, candles and odor absorbers placed in the firebox. They mask the smell for a few days.
- Stuffing the flue with insulation or a plastic bag. It is easy to forget, and lighting a fire beneath it is dangerous.
- Waiting for fall. The smell fades when the weather turns, and the soot and the water problem are still there.
When an odor needs prompt attention
- A rotten smell, or flies near the fireplace: likely an animal in the flue
- An exhaust or fuel smell near the furnace or water heater: a venting problem, to be treated as urgent
- A smell accompanied by water stains: an active leak
Schedule service in Edison
Call (862) 225-6529 or contact us online and tell us when the smell is strongest. We inspect the flue and the chimney top, find which of the causes above applies, and explain the options and the price before doing any work. For projects completed nearby, see our crown repair and cap installation in East Brunswick and the rest of Our Work.