How Smokeless Fire Pits Work (And Whether They Really Are)

A smokeless fire pit is not actually smokeless. It is a fire pit built to burn its own smoke, and when it is running properly you get a clear column of heat instead of a plume that follows you around the yard. Worth knowing the difference before you spend money on one.

Here is how it works, what it will and will not do, and whether you can cook on it.

How a smokeless fire pit actually works

Smoke is fuel. When wood heats up it releases gases and fine particles before they have had a chance to burn. In an ordinary pit those gases drift off as smoke, which means a good share of the energy in your firewood leaves without ever producing heat.

A smokeless pit gives those gases a second chance. It uses a double wall. Air enters through vents at the bottom, travels up the gap between the inner and outer wall, and heats as it climbs. By the time it reaches the top it is hot, and it comes back into the fire through a ring of holes just under the rim.

That jet of preheated air hits the rising smoke at the one place it can do something useful: above the flame, where the gases are still hot enough to ignite. They burn. You see it as a secondary flame flickering around the top of the pit, and you stop seeing it as smoke.

The engineering term is secondary combustion. The practical result is more heat from the same wood and far less smoke in your eyes.

Are smokeless fire pits really smokeless?

No, and anyone who tells you otherwise is selling something.

There are three times a smokeless pit smokes like any other:

Startup. Secondary combustion needs heat to work. For the first ten or fifteen minutes, before the walls come up to temperature, you get normal smoke. Nothing is wrong. It is just cold.

Wet wood. Energy that goes into boiling water out of a log is energy that is not available for burning smoke. Unseasoned wood will smoke in any pit, and a smokeless design cannot rescue it.

Overloading. Pack the pit full and you choke the airflow the whole system depends on. Fewer logs, more space, better burn.

Run it hot, run it with dry wood, and do not stuff it. Do that and the smoke mostly disappears. Get any of the three wrong and you have an expensive ordinary fire pit.

Can you grill on a smokeless fire pit?

Yes, and it is one of the better reasons to own one.

A smokeless pit gives you a cleaner-burning fire and a bed of coals that holds steady heat, which is most of what you want for cooking over wood. What it does not give you by default is a cooking surface. For that you need a grate that sits over the opening.

Two things to get right. First, the grate has to clear the rim without wobbling, so measure the opening rather than the pit's outside dimension. Second, cook over coals, not flames. Wait for the fire to burn down and settle. Food over open flame chars outside and stays raw inside.

Our fire pit grill grates come in 30 and 36 inch diameters in both powder-coated steel and stainless, with handles so you can lift a hot grate off without a production.

The best wood for a smokeless fire

Dry hardwood. That is nearly the whole answer.

Oak, maple, ash, hickory, and beech are dense, burn slow, and leave a long-lasting coal bed. Seasoned to under twenty percent moisture, they are what a smokeless pit is designed around.

Avoid softwoods like pine and spruce for anything but kindling. They are full of resin, they pop and throw sparks, and they coat your pit in creosote. Avoid anything painted, treated, or salvaged from a pallet. And avoid wood that has been sitting in the rain, whatever species it is.

If you are not sure whether your wood is ready, knock two pieces together. Dry wood gives you a sharp crack. Wet wood thuds.

An insert or a whole new pit?

Most people looking at smokeless pits are choosing between buying a standalone unit and keeping the stone or block pit they already have.

If you already have a masonry pit you like, you do not need to tear it out. A drop-in smokeless fire pit insert sits inside the existing opening and brings the double-wall burn with it. You get the clean fire without losing the stonework or starting over.

It also solves a second problem. An open masonry pit takes heat straight into the block, and over a few seasons that shows up as cracking and spalling. A steel insert takes the heat instead, which is why a lot of people install one as much to protect the pit as to cut the smoke.

The Burly Comfort II smokeless insert set fits round and square openings from 27 to 44 inches, has a solid vented floor, and comes with a snuffer lid so you can end the evening without a hose. Measure the opening of your pit, not the outside, and match it to the size.

If you are building the pit around it rather than dropping it into one you already have, the stonework is most of the job. We walk through it here: how to install a fire pit insert kit.

Is it worth it?

Depends what bothers you about your current fire.

If you mostly light a fire a few times a summer and the smoke does not bother you, a smokeless setup is a luxury. If you use your pit most weekends, if you have been going inside smelling like a campfire, or if the smoke is the reason guests drift away from the fire, then it changes the experience in a way that is obvious the first night.

And if you have a masonry pit that is already starting to crack from the heat, the insert pays for part of itself by stopping the damage.

Measure your opening first. Everything else follows from that number.