Why Is My Fireplace Smoking? 7 Common Problems and Solutions

There’s nothing like curling up next to a warm fire, but there’s also nothing like watching your room get a little too smokey—and that’s not a good thing. A smoking fireplace isn’t just unpleasant. It can pose a serious safety hazard. Luckily, some causes are an instant fix, and even if it’s not, the problem is common enough that a pro can readily handle it. This guide will show you why your fireplace is smoking and what you can do about it.

1. Blocked Chimney

If smoke from your fireplace is filling your room, it’s a warning sign that your chimney may be blocked. A common cause is creosote, a tar-like byproduct that builds up inside your chimney when you burn firewood. Creosote is one of the leading causes of home fires, according to the National Fire Protection Association (NFPA).

Beyond creosote, pests—especially bird nests—often cause blockages. Leaves and other debris from outside could end up inside after a storm. Even an ill-fitting chimney cap can prevent proper ventilation. The only real way to know what’s blocking your chimney is to get a chimney inspection.

The Solution

Hire a local chimney cleaner to remove the blockage. If you suspect pests, you’ll need to hire an exterminator before clearing the debris. You should clean your chimney at least once a year to prevent a dangerous buildup of creosote.

2. Closed Damper

If you forgot to open your damper before starting your fire, you may notice smoke pouring into your home. For the damper to work properly, it needs to be completely open.

The Solution

Open your damper before starting a fire. Most homes have a throat damper above the firebox that you can check using a flashlight. Open it with the handle on the door, but don’t touch it with your hands if you’ve recently lit a fire. Hot cast iron can cause serious burns. If you have a top seal damper, you can open it using a cord or cable.

3. Air Pressure Issues

You need the right balance of air pressure for your fireplace to properly vent. To maintain this, when air vents up your chimney, it needs to be replaced with fresh air from another source (known as makeup air). Exhaust fans running elsewhere in your home (think: a bathroom or kitchen) can create negative pressure (where the pressure inside a room is lower than outside of the room). This creates a backdraft in your chimney and draws smoke into your home.

Among other causes, poorly sealed attic doors can also create a backdraft as air escapes up into your attic space rather than out the chimney.

The Solution

Sometimes, turning off the exhaust fans in your home while you burn a fire can solve the issue. Opening doors and windows may also help. You may need to install new attic doors or hire a pro who can install a makeup air system (MUAS).

4. Poor Ventilation

If your home isn’t properly ventilated, it can cause smoke to pour out of your fireplace instead of up the chimney. This is common in older homes, which typically have smaller flues that weren’t designed to handle modern appliances. It can also be an issue in modern homes, which are well-insulated and tightly sealed. They may not have enough flowing into your home for the fireplace to properly vent.

The Solution

Add ventilation. If your house is well-insulated, opening a window can help, but it’s not a permanent solution. You may need to install an outside air supply vent, a chimney fan (known as a draft fan), or a makeup air system (MUAS). 

5. Weather

Weather can cause a smoking fireplace for a couple of different reasons. When temperatures are warm outside, the fireplace may not draft properly. Rainy weather or high humidity, which makes the air dense, can exacerbate this. In addition, wind can cause a backdraft, blowing smoke back into your home. 

The Solution

Be careful using your fireplace if it’s windy or rainy and if the outdoor temperature is similar to the temperature inside your home. Fireplaces draft best when it’s cold outside, but extreme cold can cause the flue to fill with high-density cold air. This will block airflow, so you’ll need to prime the chimney before lighting a fire.

6. Construction Issues

Sometimes, the problem has to do with the installation. Smoke won’t properly vent if the throat of the smoke chamber is too small, your damper or flue is the wrong size, or your chimney is too short for the height of your home. Additionally, if you have multiple flues in the same chimney, one may be funneling smoke back into your home. 

The Solution

You’ll need to hire a professional fireplace contractor who can remodel your space. This may require installing a new damper, replacing your flue, adding additional ventilation, or rebuilding your chimney.

7. Wrong Firewood

Sometimes, using the wrong kind of wood can cause a smoking fireplace. Wood with a high water content will struggle to burn and may not generate enough heat for the chimney to draw air upwards.

The Solution

Only use seasoned hardwood that has dried for six months.

When to Call a Pro

A smoking fireplace can pose a safety risk, so it’s a good idea to get it under control ASAP. If you remembered to open the damper, are using the correct type of wood, and the problem isn’t caused by the weather, bring in a local fireplace repair pro before using your fireplace further. They’ll troubleshoot the problem, which can be complicated when multiple factors impact the pressure and ventilation in your home, and make sure your fireplace is functioning correctly and safely.

How to Prevent Your Fireplace From Smoking

To prevent your fireplace from smoking, you’ll need to follow proper fireplace maintenance:

• Inspect your chimney once a year: Hire a local chimney inspector to inspect your chimney once per year. This can identify blockages, damage, and structural repairs before they become dangerous issues.  

• Clean your chimney regularly: Clean your chimney at least once per year to reduce creosote buildup and remove potential flue blockages. You may need to clean it more if you use your fireplace frequently. 

• Open the damper: Don’t forget to open the damper before you start the fire.

• Only burn seasoned hardwood: Avoid using wet wood. Never burn treated wood, cardboard, or trash which can produce harmful fumes.

• Modify your home to address the smoke: You may need to install air vents, glass fireplace doors, or an upgraded chimney liner to control the smoke. Always call a pro to make repairs.