Fireplace Smoke in House? Here Are 9 Reasons Why

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Is smoke coming back into your house when you have a fire in your fireplace? It could be due to one of these nine reasons. Get it inspected today!

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When you light a fire in your fireplace to feel its warmth while you relax on your sofa, you expect the fire to draft up your chimney and out of your life. Sometimes, however, the smoke fills your room, leaving your evening ruined.

Fireplace smoke coming back into your house is not just irritating, it can also point to a malfunction in your chimney or its parts. It can be dangerous and should be inspected immediately to avoid further inconvenience or danger.

A smoky fireplace can have various reasons which can be as simple as burning the wrong type of wood or as serious as excessive creosote buildup inside your chimney.

Let’s discuss all these causes in detail, how to solve them, and how to prevent them in the future to ensure the health and safety of you and your family.

Why Smoke From Your Fireplace Is Coming Into Your House?

#1 – The Damper of the Fireplace Is Open

A chimney damper is used to control the airflow inside your chimney and helps in adjusting the intensity of the fire. You should always open your damper before igniting the fire to let the smoke out. Most people forget to open their dampers and the smoke fills up their room.

If you’ve got a fireplace damper, you’ll either find a rod or knob just above your fireplace. In the case of a knob, twist it clockwise to open it. If you find a rod, slightly lift it and push it to open the damper.

Some people have a top-mounted damper installed at the top of their chimneys. Those people will find a metallic chain beside their fireplace. If you find the chain tightly attached to a notch, that means your damper is closed. To open it, simply free the chain from the notch to let it move upwards and open the top-mounted damper to let the smoke out from the chimney.

Once the fireplace is not in use, close the damper so that cold air from outside cannot enter your home and reduce the temperature inside.

Sometimes the smoke enters your room even when the damper is open. That’s usually caused by a faulty damper that doesn’t open properly or is stuck. Or maybe the damper doesn’t fit properly, restricting the passage of smoke. In such cases, replacing the faulty damper is your best bet at ensuring a safe and efficient chimney operation.

#2 – Burning the Wrong Type of Wood

Some woods are better for fires than others, and using the wrong type of wood can cause excessive smoke production which can smoke up your room.

According to the Chimney Safety Institute of America (CSIA), your wood-burning logs should not have more than 25% of moisture.

That is why using freshly chopped wood is discouraged since it generally has 40% to 50% of moisture.

Firewoods with a lot of moisture do not produce hot fires since a lot of energy goes into burning off the moisture resulting in denser smoke. Not only that, combustion of wet wood doesn’t occur properly resulting in a lot of creosote production.

Lastly, since wet woods do not produce adequate heat, the flue gasses remain cooler and a proper draft is not produced. This causes the smoke in the fireplace to enter your room.

Therefore, always use dry, seasoned woods for burning since they have lesser moisture, burn better, and produce lesser smoke and creosote.

#3 – The Fireplace Has Not Been Used in a While

Warm air rises above while colder air is denser and flows downwards. If you haven’t used your fireplace in a while, your chimney flue will get filled up by cold air from outside. So when you light a fire, the smoke produced as a result will be blocked by the colder air inside the chimney fule and flow back into your room.

To avoid this, you’ll need to prepare your flue by warming up the air inside for better drafting of smoke. You can do this by lighting your gas starter without the logs for a while.

#4 – Fire Is Too Big

A large, smoldering fire can cause the smoke to get inside your room. Burning smaller fires might seem counterintuitive but it is a good way of getting the draft going. Smaller fires burn faster than larger ones and produce more heat that warms the air inside the chimney and improves the draft.

Another way of improving the draft and keeping smoke from getting inside your room is to burn the fire using the top-down method.

Traditionally, fires were built with the fire starter at the top and the logs and the kindling at the bottom. Because of this, the heat required to warm up the air inside the chimney and start the draft comes a bit later.

The top-down method solves this problem by placing the logs at the bottom and the kindling above them in a crisscross. The fire starter is placed on top of it all.

Since the fire is started at the top, the air inside the chimney is heated sooner and a draft is produced to pull the fireplace smoke inside the chimney.

#5 – Flue Blockage

If you haven’t gotten your chimney swept in a while, it’s quite probable that the fireplace smoke coming inside your chimney is due to a blocked chimney.

Chimney blockages usually occur when the debris from outside settles inside your fireplace. Or when birds and nesting critters find shelter inside your chimney because of the warm and safe space it provides.

This, however, blocks the chimney and restricts the airflow inside it. Since the smoke generated during combustion has nowhere to go, it comes back into your room along with Carbon Monoxide (CO), a dangerous gas that can be fatal.

Another common reason for a blocked flue is soot and creosote buildup. Improper combustion due to moist woods or improper airflow results in denser smoke and higher production of soot and creosote. Soot and creosote are flammable byproducts of improper combustion that rise and settle inside the chimney.

Over time, these deposits enlarge and ultimately block the chimney. Not only can such deposits cause the smoke to come back into your house, but they can also increase the chances of a chimney fire.

#6 – Cracked Chimney or Gaps in Your Chimney Flue

A cracked chimney can also be a culprit. If you haven’t hired a chimney sweep for a chimney inspection in a while, your chimney likely has cracks in it that leak the smoke inside your home.

While smoke can be irritating, it’s not the only thing leaking inside through these cracks. Soot and CO will also escape from the chimney flue and enter the house causing respiratory issues and other serious health concerns.

Regular wear and tear can also create gaps in your chimney liner (flue) which can cause drafting issues with smoke escaping into your room.

#7 – Backdraft Problem Due to Multiple Flues

If you’ve got multiple flues inside a single masonry chimney, smoke can rise inside one flue and come back into your form from another.

This is a common problem for people that have two fireplaces or a stove with a fireplace connected to the same chimney.

What happens is that when one of the flues is in use while the other isn’t, smoke (being hotter) rises from one flue and enters the unused flue (which is colder) where the two flues connect.

If you don’t plan on using the second flue at all, you can get a chimney sweep to seal it.

However, if you want to use the second flue every once in a while, hire a chimney sweep service to provide the best possible solution.

If the second flue is used for another fireplace, installing a top-sealing damper will solve the problem. You can keep it closed when not in use, and open it when you plan to use it. However, if the other flue is for a furnace or some other appliance the chimney sweep might advise you either to reline the chimney or to get a chimney cap installed.

#8 – Your House Is Insulated

Modern homes are well insulated which is great. Right? Well, not if you plan on using your fireplace. But to understand why a well-insulated home might cause smoke to escape into your room, it’s important to understand the various pressure planes of a house.

A house, especially an older one, is divided into three pressure planes: neutral pressure plane, positive pressure plane, and negative pressure plane.

Neutral pressure planes are generally found right in the middle, just between the ground floor and the roof. Below that is the negative pressure plane, which means that air from outside will enter your house in this plane (area.) Above the neutral plane is the positive pressure plane, which means that air from inside will escape outside.

Modern homes have sealed windows and doorways along with exhaust fans running in your bathrooms and kitchen. Such an arrangement sets the neutral pressure plane higher in your home. This means that the negative plane (at the bottom) is much greater than the positive plane (above). This causes a downdraft inside the chimney.

You can solve this issue by opening the windows of your room in which you’ve got your fireplace. If that helps adjust the pressure planes and improves the drafting of smoke, you can consider investing in an air supply vent for a more permanent solution.

#9 – Drawing Problems Due to the Improper Chimney and Fireplace Design

Sometimes, the problem is not with a faulty damper, a blockage inside the chimney, or the wrong type of wood. Instead, the problem is more fundamental i.e. your chimney is not tall enough or maybe your fireplace is not designed correctly. Such design flaws can lead to drawing problems inside the chimney.

A short chimney, for example, cannot vent properly. The condition worsens when strong winds are blowing, which can lead to smoke and Carbon Monoxide (CO) inside the room. Not only that, the venting issues lead to exhaust gasses lingering inside the chimney which can lead to chimney fires.

Therefore, it’s important to follow the NFPA 211 standard that recommends a chimney height of a minimum of 3 ft above the point where it passes the roof. Your chimney should also be at least 2 ft taller than any trees or portions of your house or building that are within a range of 10 ft.

Sometimes the fireplace is constructed using incorrect dimensions and does not follow the recommended fireplace opening size ratio to the flue volume. If the flue volume is small, it won’t be able to process the amount of smoke generated during the fire, which will enter your living space.

Reconstruction of your firebox to fix the drawing issues can cost you thousands of dollars and is not a viable option for most people. Some people resort to chimney exhaust fans to solve the drawing and drafting issues. However, the vacuuming can be so strong that it pulls out a lot of warmth from your room along with the smoke.

The best option, then, is to use a vertical fireplace grate that brings the fire closer to the chimney and keeps it from smoking up the room. It also improves air circulation helping it to burn better.

Can Fireplace Smoke Be Harmful?

Fireplace smoke can also be harmful. Inhaling too much smoke can irritate the lungs and airways, and cause problems like bronchitis, coughing, and difficulty in breathing. If you have asthma or another respiratory condition, exposure to smoke can even trigger an asthma attack. 

Children and old-aged folks are particularly susceptible to irritation caused by smoke.

However, the problem is not just limited to smoking. With smoke comes soot that can enter your skin or even eyes causing irritation at best and serious health issues such as cancer, at worst.

Moreover, Carbon Monoxide (CO) can also leak inside your living space. CO can cause headaches, fatigue, and nausea. However, prolonged exposure can even lead to the death of an individual.

Since CO gas does not have any color to odor, it is important to install CO detectors in various rooms of your home. So that if CO gas leaks inside your house, the alarms go off and you can get yourself and your loved ones away from the danger.

Tips on How to Eliminate Smoke From Fireplace Coming Into the House

If you’re experiencing excess smoke coming into your home when using a fireplace, try taking these steps to reduce or eliminate it.

Check for Chimney Damage

We’ve talked about how cracks or other chimney damage could be allowing heat and soot to escape into your room. If you’re facing smoking issues, it’s a good idea to check your chimney for any signs of damage.

However, it might not be possible for you to check out all the areas of the chimney, especially the ones that are harder to reach. Therefore, hire a professional chimney sweeping service for a thorough inspection of your chimney.

Use Only Seasoned Wood

Choosing only seasoned, dry wood for burning in their fireplace can help reduce the amount of smoke produced and help with drafting issues. It will also reduce the amount of creosote produced.

But how do you ensure that your firewood is properly dry?

To know if your firewood is properly seasoned and dry, see if it has any visible cracks and is dark at the ends. If so, your wood is seasoned. If your wood looks fresh, it probably has a lot of moisture. You can also check the weight. Dry woods are usually lighter due to lesser moisture. Another way is to beat two pieces of wood together and hear the sound they make. Dry woods would make a ‘clunk’ sound while woods with greater moisture content will make a ‘thud’ sound.

However, the most accurate way to check the moisture of your woods is to use a moisture meter. To use a moisture meter, cut the wood log in the middle and check the moisture where you split the log. If the moisture reading is more than 25%, the wood log needs to be seasoned.

Light Smaller Sized Fires

Using the right size of your fire can minimize the amount of smoke escaping into your home. That’s because smaller fires produce heat faster which allows the air inside the chimney to get warm. Warmer air produces better drafting, ensuring proper ventilation for your fireplace and that smoke will not enter your room.

Don’t Burn These

Trash such as pizza boxes, wrapping paper, or cardboard creates a lot of heat and should not be burned inside your fireplace as it can lead to a chimney fire. Moreover, these materials are often colored, meaning they have chemicals and toxins that will disperse in the air when burned causing health problems.

Plastics and styrofoam should also be avoided as these materials are teeming with harmful toxins and produce black smoke when burned. The black smoke can stain your house.

You should also avoid using gasoline or any other petroleum product as an accelerant because the fire can get out of control, putting yourself and your loved ones in danger.

Schedule Annual Chimney Inspections

One of the best things you can do to keep smoke outside your room and for the proper functioning of your chimney as a whole is to schedule regular cleaning and annual chimney inspection.

The inspection, as well as the cleaning, should be conducted by a professional chimney sweep or service for the best possible results.

It will ensure that any build-up of creosote or other materials that might be blocking your chimney are removed before they have a chance to cause problems.

The Takeaway

If your fireplace smoke is leaking inside your home instead of drafting out of your chimney, you’ve got a serious problem at hand that can be irritating and hazardous to your health and that of your family.

The problem, however, is that fireplace smoke coming into the house can be caused by several reasons. It could be due to a faulty fireplace damper, improper fireplace construction, smaller chimney size, chimney blockage, creosote build-up, or something else.

To get to the bottom of it, the best way is to hire a professional chimney sweep or service. These certified professionals are well trained, educated, and equipped with all the tools required for a thorough chimney inspection. Moreover, their years of experience allow them to diagnose the problem swiftly and solve it efficiently without causing further damage.

In the process, they might also detect and solve any other underlying issues that may cause damage or risk your safety in the future.

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Thomas Green

Thomas Green

Thomas has worked in the Chimney & Fireplace field for over 12 years. He is an expert in his trade and loves to help People with their needs. Thomas Write helpful articles so that homeowners can make the most informed decisions about their fireplace and chimney.