Relaxing by the fireplace is supposed to be enjoyable, therapeutic, and calming. However, certain fireplace and chimney issues can create an uncomfortable experience and allow smoke to vent back into your home. Fortunately, we’re here to help! SirVent Lexington has a team of professionally trained and certified technicians ready to examine your chimney and figure out why smoke is venting back into your home. Read below to learn more, then give us a call to schedule an appointment today!

Flue Blockagessmoky chimney against gray sky

Smoke blowing back down your chimney and into your home is called a downdraft. There are many different causes for downdrafts, such as flue blockages. The flue must be clear of obstructions for the smoke to properly vent out of your home. Even a small partial blockage can create a downdraft.


Creosote is one of the most common causes of flue blockages. This is a black tar-like substance that is a byproduct of burning wood. Over time, it builds up and sticks to the flue walls. It can eventually block part or all of the flue, which will cause a downdraft. It is also highly flammable, so this buildup is jeopardizing your home and family’s safety. Fortunately, our professional technicians can easily clear your chimney flue of any creosote buildup. During an annual inspection or sweeping, we examine the flue and remove any excess creosote. We can even use PCR to remove glazed creosote, which is hardened creosote caused by neglected chimney maintenance.


Debris such as sticks, leaves, branches, and twigs can also cause flue blockages. They can fall into your chimney from nearby tree limbs, so be sure to regularly trim any overhanging branches near your chimney. They can also be brought into your chimney by animals and used as nesting materials. Chimneys are a prime nesting spot for animals such as birds, raccoons, squirrels, chipmunks, and more. They are looking for a warm, safe, and dry spot to hide from predators and the elements, and chimneys check all the boxes. The debris from nesting materials or overhanging branches is also a major fire hazard, as a smoldering ember could easily ignite the debris. Fortunately, closing off your chimney with a cap will prevent any unwanted debris or animals from entering, which will, in turn, prevent flue blockages and downdrafts. Chimney caps sit at the top of your system and close off the flue from water, debris, animals, and other outside elements. SirVent can install or replace any chimney cap with ease!

Damper Issues

Damper issues can also cause smoke to blow back into your home. The damper is responsible for closing off the flue when the fireplace is not in use. By opening when the fireplace is active, it allows smoke to travel up the flue and out through the chimney. Traditional dampers sit in the “throat” of the chimney and often allow downdrafts because they are not as airtight as modern top-sitting dampers.

At SirVent, we sell and install two types of dampers that help prevent smoke from blowing back into your home. Lock-Top dampers are made of stainless steel and silicone rubber gaskets. They are simple to operate, long-lasting, inconspicuous, and highly effective. National Chimney’s Premier damper caps are very similar to Lock-Top dampers but they are larger and use mesh instead of gaskets. They have an insulated lid that seals off your flue. Both of these dampers will not only prevent smoke from blowing back into your home…their airtight seal prevents air from escaping your home, which will lead to lower heating and cooling costs!

Chimney Height and Home Pressure

Your chimney’s height and home pressure can also cause smoke to blowback in your home while using your fireplace. The Chimney Safety Institute of America (CSIA) uses the Neutral Pressure Plane (NPP) as a measurement of home air pressure. When your home’s air pressure is above this plane, indoor air tries to force its way out. When it is below the plane, your home is trying to draw air in from the outdoors. An unsealed chimney is an optimal place for air to enter when air pressure is below the NPP, and this can create downdrafts that blow smoke into your home. Fortunately, we can install a damper or cap to help seal off your chimney and eliminate any downdrafts.

Taller chimneys draft better because hot air naturally rises. If your chimney is deemed too short to properly vent smoke out of your home, our professional technicians can add height through skilled masonry work!

Schedule an Appointment Today!

Smoke blowing back into your home can render your fireplace unusable. If you want to comfortably relax by the fireplace, give us a call at (859)-900-0402 or schedule an appointment online today! Our excellent track record of service in the Lexington, KY area speaks for itself, and we’ll have your fireplace fixed in no time!