November 6, 2026

What to Burn in a Fireplace, and What to Leave Out

Dry, untreated firewood only. Here is what belongs in a fireplace, what never does, and why the fuel you choose shows up later in the chimney.

For a wood-burning fireplace, burn dry, untreated firewood and follow the instructions that came with the appliance. That is the whole rule, and most fireplace problems that start with fuel start with one of two things: wood that is wetter than it looks, or something in the firebox that was never firewood to begin with.

Wet wood produces more smoke and contributes to creosote buildup. It is one factor among several though, not the whole story. Airflow, how the fireplace is operated and the condition of the chimney all matter too, which is why the Chimney Safety Institute of America treats buildup as a maintenance question rather than a fuel question alone.

How to tell if your firewood is dry enough

Quick answer

Use a moisture meter on a freshly split face. EPA guidance is to burn wood at or below 20 percent moisture.
Split it, stack it off the ground, cover only the top, and test before you burn.
Color, cracked ends and weight are only guesses. Wood can be dry outside and wet inside.

The reliable way to know is a moisture meter. Split a piece, press the pins into the fresh inside face, and read it. The EPA’s wood-burning guidance is to burn wood at or below 20 percent moisture, seasoned and stacked so air can move through it. If the reading comes back higher, put the piece back and give the stack more time.

Getting a stack to burnable condition

Split itSmaller pieces dry from the inside out far faster than rounds.

Stack it off the groundPallets or rails. Ground contact wicks moisture straight back in.

Cover the top onlyLeave the sides open so air moves through the stack.

Test before you burnSplit a piece and meter the fresh face, not the weathered end.

How long drying takes depends on the species, the split size and where it is stored, so there is no single answer for a given stack.

Appearance can be suggestive, but it does not measure anything. Checked ends, gray color and a lighter feel are all consistent with drier wood. They are also consistent with a piece that is dry on the outside and wet in the middle, which is exactly the piece that smokes.

One Long Island detail worth knowing: a stack kept in a damp garage or against the north side of a house can sit for a full season and barely move. Air and sun do the work, not time on its own.

Split seasoned firewood stacked beside a wood-burning stove with a glass door and an active fire inside — Dry, untreated firewood is the only fuel a wood-burning appliance should see. Split it, stack it so air moves through, and test a fresh face before it goes on the fire.

What never goes in the firebox

Keep these out

✗Treated, painted or stained lumber. Burning it can release chemicals into the room and deposit them in the flue. Construction scrap is not firewood.

✗Pallets and manufactured boards of unknown origin. The problem is that you cannot tell what has been applied to them or spilled on them.

✗Cardboard, wrapping paper and glossy paper. These burn fast and light, and can carry large flaming pieces up the flue.

✗Christmas trees, branches and other green or resinous material. Freshly cut evergreen is wet and burns poorly.

✗Driftwood. The salt is the issue, and it is easy to reach for on an island.

✗Anything wet, in the hope it will dry out in the firebox. It will spend the fire’s energy driving off water instead.

✗Gasoline, lighter fluid or any accelerant. Never, on any appliance.

The evergreen point is about condition and preparation, not a rule against all softwood. Properly seasoned softwood firewood is a normal fuel in plenty of places.

Why fuel choice shows up in the chimney

Quick answer

Wetter wood makes cooler smoke, and cooler smoke leaves creosote on the flue walls.
CSIA guidance for masonry fireplaces is to sweep once soot reaches one-eighth of an inch, and sooner if glaze is present.
Dry wood slows buildup, but it does not replace the yearly check.

Smoke that cools on the way up leaves deposits on the flue walls. Those deposits are creosote, they are combustible, and more than one form of them can be present in the same chimney, from a light soot to a hard glaze.

From fuel to flue

Wetter fuel, cooler fireMore of the fire’s energy goes into driving off water, so the smoke leaves cooler.

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Cooler smoke condenses soonerIt deposits on the flue walls rather than leaving the top.

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Deposits accumulateSoot first, and in some conditions a hard glaze that a brush will not take off.

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Sweeping threshold reachedCSIA’s guidance for masonry fireplaces is to sweep once sooty buildup reaches one-eighth of an inch, and sooner if glaze is present.

CSIA homeowner resources. That one-eighth of an inch figure is written for masonry fireplaces. A factory-built system or a stove follows its own manufacturer requirements.

Burning dry wood tends to slow that process down. What it does not do is guarantee the annual check finds nothing, and it is not a reason to skip one. If you want the frequency question answered properly, we covered it in how often a chimney should be cleaned.

Open fireplace door showing accumulated ash and soot inside the firebox, with a collection bag alongside — Deposits on the flue walls are what sweeping removes. Fuel choice changes how fast they build, not whether they need to come out.

A quick guide for the wood pile

Before it goes on the fire

What you notice	What to do
Meter reads 20 percent or below on a fresh split face	Good to burn. Keep the rest of the stack covered on top and open at the sides.
Meter reads above 20 percent	Put it back. Re-split, restack and test again later. Do not burn it to dry it.
No meter, and the piece is heavy with tight, smooth ends	Treat it as not ready. Weight and uncracked ends both point to water still in the wood.
It came from a job site, a skid or a demolition pile	Leave it out. Unknown treatment is reason enough on its own.
It is a cut tree, branches or yard trimmings	Not this season. Green material is wet material.
It washed up on the beach	No. Salt does not belong in a flue.

A meter is the only item on this list that measures anything. Everything else is a reasonable guess.

What good fuel does not fix

Quick answer

Fuel cannot fix a cracked liner, a blockage, water getting in, a poorly drafting flue or old glazed creosote.
If smoke comes into the room, stop using the fireplace and have it checked.

Fuel is the part you control daily, so it is worth getting right. It is also the part that gets over-credited. These are chimney conditions, and no fuel choice addresses any of them:

A liner that has cracked, shifted or deteriorated.
A blockage from debris or an animal nest.
Water entering at the crown, the cap, the flashing or open mortar joints.
A flue sized or built in a way that drafts poorly.
Glazed creosote already present from previous seasons.

If smoke is coming into the room rather than going up, that is a different problem with its own answer: stop using the fireplace and have it assessed, which the EPA says plainly as well.

Chimney technician standing inside a large brick chimney flue, inspecting the walls with a work light — None of the conditions in that list is a fuel problem. They are found by looking up the flue, which is what an inspection is for.

A note on gas appliances

Quick answer

Never burn anything in a gas fireplace or gas logs that the manufacturer did not specify.
Electric fireplaces have no fuel and no chimney, so none of this applies.

None of the above applies to a gas fireplace or gas logs. You do not add fuel to those, and nothing should ever be burned in them that the manufacturer did not specify. Decorative media, logs and placement are all part of the appliance’s listing, so the instructions govern. We compared the two kinds of upkeep in gas and wood fireplace care.

Electric fireplaces have no combustion at all, so there is no fuel question and no chimney involved.

Questions homeowners ask

Can I burn softwood like pine?

Yes, if it is properly seasoned to the same standard as any other firewood. The common warning about pine is really a warning about resinous, unseasoned wood. Season it, meter it, and it burns like other fuel. Wet pine behaves like any other wet wood, which is to say badly.

Is it safe to burn the Christmas tree once it dries out?

Keep it out of the fireplace. A tree that has been indoors is dry on the needles and still green in the wood, it burns extremely fast, and it can carry flaming material up the flue. Put it out for pickup.

Does burning a hot fire clean the chimney?

No. There is a persistent idea that a very hot fire burns deposits off the flue walls. What a hot fire can do is ignite them, which is a chimney fire. Removal is mechanical, and it is done by a sweep.

I only use the fireplace a few times a year. Do the same rules apply?

The fuel rules do, yes. Light use changes how fast deposits accumulate, not what happens when wet or treated material is burned. Light use also does not stop animals, water or debris from getting in between seasons.

What about those creosote-removing logs?

Treat them as a supplement at most. They do not remove deposits from the flue walls and they are not an inspection. Whatever a product claims, nobody has looked up the chimney afterward except a person with a light and a camera.

Next step. Ageless Chimney works across Nassau County, Suffolk County and Queens. If the wood pile is sorted and you are not sure when the chimney was last looked at, contact the office to discuss a chimney cleaning or an inspection. It is also worth describing anything you have noticed, because a smell, a stain or a fire that will not draw all point somewhere.