Why Is There Condensation in My Wood-Burning Stove?

Condensation in a wood-burning stove can be both annoying and perplexing since water, an unexpected element, accumulates without a clear source, leaving you wondering why it occurs.

Condensation may form inside your wood-burning stove or its chimney if the stove does not operate optimally. It typically occurs when wet wood is burned and too much smoke is produced. The gasses and fumes produced by the stove cool down in the flue, and seep down into the burner. 

Want to know more about the reasons for this problem and possible solutions? Read on to find the discussion useful!

Wood-burning stove and condensation

Your wood-burning stove can get moist and it’s a pretty common issue. This problem can appear in three different ways. 

First, you may notice condensation on the outer surface of your wood stove. It indicates a high level of humidity inside your home. Humidity condenses only when the surface of your stove is cold, so the problem usually occurs when your do not use your stove for a few days. 

If this is the case, condensation will also appear in other areas of your home, such as on the windows. During cooler months, the ideal indoor humidity is between 30 and 60%. However, you can easily control moisture in your home if the moisture level is too high. 

Second, condensation may appear inside your wood stove. This is an indication that the stove is not working well. The gasses in the flue get cool before exiting, and thus create condensation. Drops of water seep into the stove. If you do not take action, the condensation will cause rust and corrosion. 

Third, there may be tar condensation in the stove. This indicates that there is way more tar inside the flue. The tar can solidify and thus significantly reduce the efficiency of the stove. 

It is important to note that condensation can appear in a sophisticated range cooker as well, such as Rayburn, because it has a similar mechanism

Why is there water in my wood-burning stove? 

There may be one or more of the following reasons for the presence of water in your wood stove. 

First, if you notice water seeping down the stove pipe on the outside, the most likely reason is an insufficiently sealed or improperly installed storm collar. There is a seal between the storm collar and the pipe. If, for any reason, the seal opens up, water will start leaking from your wood stove. 

Next, if there is black water leaking out of your wood stove pipe, you are probably burning too much wet wood. When you burn moist wood, the stove does not operate at its full capacity, and therefore the flue gets only slightly hot. 

The flue surface cools down quickly, causing the steam to condensate. Consequently, you may notice water running down the stove wall. Unless you stop using damp wood, at a point black water will start running down the stove pipe. 

Another reason for such an issue is that your stove is probably not working hard enough. Using too much moist wood is the main reason a unit fails to work at the right temperature. 

If you want to get a temperature reading of the stove, put the thermometer into the stove, not on the flue. Doing the latter, you will end up getting a misleading reading, so you won’t know if the stove is working at a significantly lower or higher temperature. 

Rainwater can also get into your stove during heavy rain. There’s a rope seal around the top of the flue. Rainwater can seep through the rope seal and start leaking into the furnace. 

Dangers of condensation in a wood burning stove

If left unattended, condensation in a wood-burning stove can cause rust and corrosion. This is because condensation is acidic in nature. The corrosion eventually leads to perforation, and at a point the stove stops working. 

The tar-like, black flaky residue can completely block the chimney. The residue is often volatile, so it can cause ignition and lead to a dangerous chimney fire. 

Also, it is hard to ignite wood and keep a fire going if the inside of your stove is damp. 

These technical issues will be there as long as you keep using a wood stove. If you want to stop or reduce your use of solid fuels, consider investing in an air source or ground source heat pump. A heat pump is good for the environment because the unit does not require combustion. 

How to prevent condensation in a wood burning stove

If you notice condensation in your wood-burning stove, the first thing you have to do is to find out the underlying reason. The problem will go away once you have taken measures. However, it is better to prevent condensation from forming in the first place. Here are some preventative measures that are worth-trying: 

  • Wet wood creates plenty of smoke that leads to condensation. So, burn only dry, seasoned wood. Properly seasoned wood means wood that has been cut and left to dry for at least 6 months
  • The size of the chimney flue should be right for the stove. Too small a flue will cause a buildup of steam. Also, the chimney should be properly connected to the stove. 
  • When the stove is out of use, consider applying some light machine oil on the inside of the stove. This oil keeps out moisture and prevents rusting. 
  • It is okay to slumber (operate at a very low temperature) your wood-burning stove, but don’t do it most of the time. If the stove is always set at a low temperature, the smoke will condense, and at a point the flue might get blocked. 
  • Make sure the room in which the stove is installed has plenty of ventilation. 

Condensation in a fireplace chimney

Condensation in a fireplace chimney usually results from a lack of ventilation. It happens when airflow inside the chimney becomes restricted, the smoke and fumes turn cold and then condenses. 

Normal chimney condensation on the outside of the chimney, a condition often referred to as chimney sweating, is not always considered a problem. 

It can happen during the cold season even when there is adequate ventilation inside the chimney. As the warm air inside your home comes in contact with the cold surface of the chimney, the air condenses. Chimney sweating is more likely if there is a high level of humidity inside your home. 

Poor insulation is another potential reason behind condensation in a fireplace chimney. If the chimney is inadequately insulated, the air and fumes inside the chimney may cool down too quickly, leading to condensation. 

The condensation in the chimney can freeze and then thaw. This cycle of freezing and thawing can damage the structure. 

You can reduce the risk of, even prevent chimney sweating by installing a flue liner. It slows the cooling of the chimney walls by isolating the air from the walls, and thus significantly reduces the formation of condensation on the outer surface of the chimney. 

If there are leaks in the chimney, address them immediately. To detect the leaks, consider getting the help of a chimney specialist. 


Condensation forming in a wood burning stove is a pretty common problem and has easy solutions. However, if you leave the issue unattended, it can lead to rust and corrosion, making the stove inefficient, even out of order. 

In most cases, you can prevent condensation just by burning properly seasoned, wet wood. If it persists after you’ve switched to seasoned wood, most probably the stove is not installed properly, the chimney is insufficiently insulated, or there is a leak. 

If you are not able to address the issue on your own, consider getting in touch with a stove installer or chimney specialist. We hope now you are ready to take action.