The first fire of the season is the one most likely to expose a problem. Over the warm months, a chimney can fill with a bird’s nest, a fallen cap or a layer of creosote, and a liner can crack without any sign from inside the room. You light the fire, and the smoke has nowhere safe to go. A pre-season check takes an afternoon and costs far less than a chimney fire or a carbon monoxide emergency.

Why chimneys fail

Wood smoke carries unburned particles and vapors. As they cool against the flue wall, they condense into creosote, a tar-like residue. According to the Chimney Safety Institute of America (CSIA), if creosote builds up in sufficient quantities and the internal flue temperature is high enough, the result can be a chimney fire. Burning damp or unseasoned wood, or running a stove with the air supply choked down, produces more creosote.

Fireplaces and chimneys are a smaller part of the fire picture than cooking or heating equipment, but they are not trivial. Erie Insurance, citing NFPA, reports that fireplaces and chimneys were responsible for seven percent of U.S. residential fires between 2016 and 2020. The more immediate danger to a family is often not flames but a blocked or leaking flue that pushes carbon monoxide into the house.

The annual inspection

NFPA 211, the standard for chimneys, fireplaces, vents and solid fuel-burning appliances, calls for these systems to be inspected at least once a year, with cleaning and repairs done as needed. CSIA describes the basic, Level 1 inspection as a visual check of the readily accessible parts of the fireplace and chimney, without special equipment and without climbing onto the roof.

Hire a CSIA-certified sweep, or a technician who can show comparable credentials, to do it. Ask for a written report. Ask for a camera inspection if any of the following is true:

  • You have just bought the house or are lighting a fireplace for the first time.
  • You have changed the appliance, for example by installing a wood stove or an insert.
  • There was a chimney fire, a lightning strike, an earthquake, a hurricane or another event that could have damaged the flue.
  • The chimney has not been inspected in years.

Book the visit now. Sweeps are busiest at the first cold snap, and a December appointment can mean a long wait.

What you can check yourself

You can do a basic walk-around before the professional arrives.

  • Cap and crown. Look at the top of the chimney from the ground with binoculars. A missing cap lets in rain, animals and debris. A cracked crown lets water in.
  • Damper. Open and close it. It should move freely and seal properly.
  • Firebox. Look for cracked or missing bricks or crumbling mortar. A stove should not have visible cracks in its body or door gasket.
  • Hearth and surroundings. The hearth should extend far enough in front of the opening to catch embers, and nothing flammable should be on the mantel, nearby or overhead within the clearance in the manufacturer’s manual.
  • Stove pipe. Check that joints are tight and screwed together and that there is no rust-through.
  • Signs of trouble. Smoke that comes into the room, a strong smoky smell when the fireplace is not in use, soot stains on the wall around the opening and flaking, shiny black deposits in the flue are all reasons to stop and call a professional.

Fuel: season it, store it, and mind the ashes

How you burn matters as much as the hardware.

  • Burn well-seasoned hardwood that has dried for several months to about a year. Unseasoned wood is wet, smokes heavily and builds creosote quickly. A wood moisture meter is inexpensive.
  • Never burn trash, cardboard, treated lumber, paint or plastics. They can release toxic fumes and damage the appliance.
  • Store firewood outdoors, off the ground, and away from the house. Bring in only a day’s supply, so you do not invite insects or damp wood indoors.
  • Never use gasoline or other flammable liquids to start or revive a fire.
  • Keep a metal screen or glass doors closed on a fireplace, to catch sparks, and keep the area in front of it clear.
  • Put ashes in a covered metal container, set on a non-combustible surface away from the house, garage and woodpile. Ashes can hold live embers for days after the fire appears to be out.

Carbon monoxide: the alarm you cannot skip

A properly drawing chimney should carry combustion gases outdoors, but any solid-fuel appliance can spill carbon monoxide into the house when the flue is blocked or the house is under negative pressure, for example because a powerful exhaust fan is running. Install a carbon monoxide alarm on each level of the home and outside sleeping areas, test it monthly, and replace it according to the manufacturer’s date. Ready.gov’s winter weather guidance repeats the same warning: install CO detectors on every level of your home. Our carbon monoxide and generator guide lists the symptoms and what to do if the alarm sounds. If the alarm goes off, get everyone outdoors first and call 911 from outside.

The first-burn routine

Once the inspection is done, light the first fire of the season with care.

  1. Open the damper fully before you light anything.
  2. Start with small, dry kindling and a small fire. Let the chimney warm up gradually.
  3. Check that the draft is pulling smoke up and out. If smoke rolls into the room, put the fire out and do not relight it until a professional has checked the flue.
  4. Never leave a fire unattended, and make sure it is fully out before you go to bed or leave the house.
  5. Keep a working smoke alarm and a fire extinguisher within reach of the room.

If the fireplace will be your only source of heat in an outage, test it before you need it, and read how backup power and heating options compare. A fireplace that has been inspected and burned a few times is a dependable backup. One that has not been lit in years is a guess.