Why do fireplaces smoke

A faulty fireplace design could impede on the drafting capabilities of your fireplace. Factors such as flue volume, fireplace opening size, damper size, chimney height, and smoke shelf construction can all play a role in the function of your fireplace. Smoke from burning wood is not good for your health. While it smells good, you should not breathe it in.

Wood smoke contains fine particles that can irritate your eyes and respiratory system. Heavy smoke inhalation can cause serious health problems, such as:. Along with these dangers of inhaling fine particles, wood smoke also contains toxic and harmful air pollutants, such as carbon monoxide CO , benzene, formaldehyde, acrolein, and polycyclic aromatic hydrocarbons PAHs. Without proper drafting and ventilation, these pollutants can harm your health.

You should address your smoky fireplace as soon as possible and install a CO detector in your home to warn you when CO levels increase. You should clean your chimney at least once a year, and more often if you use your fireplace heavily. The presence of soot and creosote can fuel a chimney fire that at the very least, could damage your chimney, and at worst, spread to your roof and home. Damp firewood produces more smoke than a flue can handle and will cause back-puffing.

If you experience fireplace smoke in the house, try stocking up on a new batch of firewood and go from there. A cold flue or cold air in the chimney is also a common cause for fireplace smoke in the home. When the air inside your flue is too cold, it forces smoke back down into your home because colder air is more dense. In order to combat against a cold flue, you can prime the chimney before you light a full fire by burning some newspaper, kindling, or lighting the gas starter if equipped before the actual logs.

Doing this will warm up the flue and make way for smoke. Additionally, slightly cracking a window or door for the first few minutes of lighting your fireplace will help release the negative air pressure within the home. This will force the heat to rise and the fireplace to draw which in return the flue to heat up and the fireplace to vent properly. This occurrence is frequent in newer, tightly seal homes.

If you consistently have this problem when burning fires, you should seek out a local chimney professional to help diagnose the real problem behind your fireplace back-puffing.

Depending on how often you use your fireplace, you might begin to experience fireplace smoke in your home. A big contributor to this problem is a dirty chimney. A general rule of thumb is to get your chimney cleaned every face cord of wood or every two years, whichever comes first. To help prevent your fires from smoking, try not to start fires during very windy weather or when temperatures outside your home are higher than inside. Windy weather can cause a backdraft, which is where air is forced back down your chimney and can affect how well the usual draft works.

For the draft to be started and for there to be movement of air up the chimney the temperature of the air within the chimney needs to be higher than that of the outside air temperature. The temperature difference between the inside and outside of your home helps warmer to air to rise up your chimney and in turn suck more air into the fireplace to replace it.

Typically, the greater the temperature difference the greater the draft. When temperatures outside your home are too high it can be hard to start the draft, meaning that a fire can struggle and smoke due to lack of continuous and sufficient airflow through the fireplace. Save my name, email, and website in this browser for the next time I comment.

To help keep smoke from coming out of a fireplace: Use a fireplace grate to help lift the fire off the hearth, or use a grate that keeps the fire against the back wall of the fireplace. Build fires more towards the back of the fireplace. Build fires using the top-down method to provide a cleaner burn sooner into a fire. To help reduce the amount of smoke that your fires are producing: Burn dry, low moisture content wood. Fully open the damper prior to having fires.

Preheat the air within the chimney before starting a fire. Build smaller but hotter fires. Open any external air vents or windows within the room to help supply the fire with sufficient fresh air. Use A Fireplace Grate A fireplace grate helps to lift the fire further off the floor of the fireplace. In older houses and oftentimes tall houses, the negative pressure rarely exceeds 8 Pascals, which is about the difference in pressure in 10ft.

Furnaces and fireplaces usually perform well pulling against a negative pressure of up to 8 Pascals. Modern houses, however, tend to be more tightly built using spray foam insulation, caulked windows and sealed doorways.

They also tend to be full of powerful kitchen and bathroom exhaust fans, so the neutral pressure level may be higher in the house if it exists at all. This means the negative pressure in the lower areas of the house can far exceed 8 Pascals, causing a downdraft in a chimney. You can help reduce stack effect in your home by stopping air leaks in the uppermost parts of your house, including attic access hatches, ceiling light fixtures, and poorly fitting windows.

In this case, the stack effect can only be corrected by adding as much air to the house as is being blown out of it, i. Chimney height can also create a downdraft situation if the chimney does not extend high enough into air with a low-enough density to create an ambient updraft.

In general, a taller chimney will typically draw better. If your fireplace smokes because your chimney is too short, the problem is likely worse when the wind blows. Not only is a too short chimney unlikely to vent properly, it may also be a serious fire hazard, risking setting the roof on fire.

While not universally true, we recommend following the rule — a chimney must be 2ft. That said, if you are constructing a chimney, we always recommend consulting a professional as well as checking local building code. A throat or smoke chamber that is too tight for the size firebox will create smoke draw issues. The throat front and back should fit well at the top of the firebox and not restrict the opening air space.

If you have a throat damper, ensure it does not restrict the throat opening either. Check to see if firebrick or other material has been added to the back of the throat, which would reduce the throat opening area and should be removed. Feel around for smooth, streamlined surfaces with no obstructions that would restrict or redirect air flow. For a fireplace to draw well, you need to be sure the flue size is adequate for the amount of smoke that can be created in the firebox.

A good rule of thumb is that the fireplace opening be no more than x the area of the flue. A smaller flue simply can't process the amount of smoke, causing some to spill back into your home. Flue size should be matched to firebox size in accordance with Section R And remember, bigger is not always better. Your flue should be the appropriate size for your fireplace.

If a flue is too large, the amount of heat produced by a small fire might not be enough to drive the draft upward. A house that has multiple flues sharing one chimney chase may transfer smoke to one another when one is burning and the other is not, causing smoke to reenter the home. When you light a fire in one fireplace, you are creating a negative pressure inside the house.

If the house is fairly airtight then the easiest way for the fire to get air is through the open flue of the other fireplace —in other words the smoke goes up the chimney and gets sucked back down the other flue along with the necessary fresh air. To fix this, you can extend the height of the flue that is causing the smoking to make one flue higher than the other.