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Basic Chimney Sweep & Repair Blog

Combustion And Draft In Your Chimney

When Basic Chimney Sweep & Repair technicians come to your home for a chimney sweeping appointment, you’ll probably hear us talk a lot about byproducts, and creosote, and the combustion process. Those topics are kind of the basic building blocks of why chimney sweeping is so important — combustion in your fireplace creates byproducts, including creosote, which build up on the flue walls, affecting draft, potentially damaging your flue liner and, if left unswept, leading toward a fire hazard.

It's good to know about the combustion process and how draft occurs so that you can prevent accidents related to your chimney

It’s good to know about the combustion process and how draft occurs so that you can prevent accidents related to your chimney

If you’ve ever wondered how the combustion process works inside your fireplace or flue, you’re not alone — we give a fireplace and chimney combustion rundown to a lot of clients, because it helps to have a sense of how things work when you’re trying to make informed decisions about the care of your chimney system.

Here are some of the basics:

Combustion In Your Chimney System

Combustion, at its most basic, is burning — or, if we’re talking the dictionary definition, a speedy chemical process that results in heat and light. When we’re focused on your chimney system, by referencing combustion, we’re talking about the process of burning fuel inside your firebox — be it wood, wood pellets or gas. You start your fire or hit your gas ignition switch, the fuel burns, heat and light result, and you get what you’re looking for out of your fireplace or stove.

Heat and light aren’t all that follows, though, and as chimney technicians, our job has a lot to do with keeping up with the other stuff — namely, byproducts and draft.

Draft And How It Occurs In Your Chimney

Draft is the force that pulls heat and byproducts up your flue, and out of your home, so proper draft is key to your chimney’s function. It occurs in your flue because of a principle we all know well: hotter air rises, and cooler air sinks. Air always moves from an area with higher pressure to lower pressure, and aressure difference occurs while combustion is happening in your fireplace or stove — hot air rising in your flue creates a lower-pressure area below, and that pulls in cooler air near your firebox opening, and draft moves along as it should.

What Can Impede Draft?

Issues with smoke, stains, odors and improper burning in your combustion appliance often have something to do with impeded draft. The specific culprits behind that impeded draft, though, can vary.

It could be something simple, like a failure to open your chimney damper all the way, or a lack of sufficient combustion air (that lower-temperature air getting pulled into your firebox). The latter happens a lot in homes with well-sealed energy-efficient windows and doors, and if cracking a window when you have a fire clears up the issue, you’ve found your culprit.

Draft problems could also be due to a size issue. A chimney that isn’t the correct height won’t achieve the right level of draft, and a flue that’s too big or too small in diameter will lead to draft issues, greater byproduct production and less efficient burning, among other issues,

Often enough, Basic Chimney techs find that draft issues are the result of flue liner damage. If your flue liner is cracked, or spotted with voids or gaps, it limits the force of your draft. Think of it kind of like a straw: Apply some force to an intact straw, and your drink comes right up; try with a straw that has a hole in it, and you’ll struggle and struggle with little success. That’s why it’s key to have your chimney inspected annually, and to have flue liner damage taken care of as soon as possible.

If you have any questions about combustion or draft in your chimney, Basic Chimney Sweeps is always here to help – just give us a call!

 

By Ronald Caillais on December 28th, 2013 | Tagged with: Tags: , , , , | Leave a Comment

Save Energy, Get Warm

Increasing Energy-Efficiency

Feel like you haven’t been getting the most out of your fireplace lately? Is your fire not quite warming you up? Are you hassled with smoke? Going through firewood a little too fast? An energy efficient fireplace is one that is performing its best. Don’t settle for less! At Basic Chimney, we’re huge supporters of efficiency. Below are some diagnostic tools to help you get maximum performance from your fireplace. And remember, one of the best things you can do for your fireplace is to maintain the chimney’s annual cleaning.

The great thing about increasing energy-efficiency in your home is that you will also save money.

The great thing about increasing energy-efficiency in your home is that you will also save money.

Can’t quite get warm?

If your fires aren’t heating your space as well as you’d like, you should consider changing the type of wood you’re using. If your wood isn’t seasoned or is damp, it takes a lot more energy from the fire just to stay burning, because it has to work so hard just to warm that water up in order to burn the wood. We always recommend burning seasoned, dry hardwoods. Hardwoods don’t necessarily burn at higher temperatures, but they do burn more slowly, which will help you get a nice, hot fire that burns for longer. Another trick to heating up that fire is to have tempered glass doors installed. This minimizes the fire’s consumption of warm air from your home.

Smoke gets in your eyes.

Yeah, it’s a beautiful song, but it’s not a beautiful thing. Not only is smoke a pest to the eyes and throat—it’s also dangerous for your health. If your fires are smoky, you might have a little work cut out for you. Sometimes it’s a quick and simple fix, and sometimes it takes a little trial and error. Follow these steps to determine what’s causing the problem:

  1. Check your firewood. As I said above, be sure your wood is dry and seasoned. Damp or green wood takes a lot longer to heat up, which prevents complete combustion (when the fire heats up enough to burn clean and combust its fuels) and doesn’t do much except produce smoke.
  2. Open your damper. It’s easy to forget things, so check to be sure that your damper is all the way open when you’re ready to light a fire.
  3. Open a window or door. It might seem counterintuitive to let the cold air in, but that might be exactly what your fire needs to get going and heat up your home. Fires consume a lot—and I mean a lot—of air. It’ll use up all the air in your about three times during 24 hours of operation. If it runs out of air supply, it’ll start pulling it down through the chimney, which forces the smoke back down and into the home.

My firewood is disappearing before my eyes!

It isn’t magic, either. Just like I mentioned above, hardwoods will burn at a high and consistent temperature if they are dry and seasoned. They also burn longer, which will get you more for your money. Remember, though—you’ll still want to keep a little soft wood on hand for kindling, since you want something that will burn a little faster to get the fire going.

Tried it all and still no luck? Give us a call and we’ll help you get well on your way to a healthy, clean fireplace that will keep you warm for years to come.

By Ronald Caillais on November 22nd, 2013 | Tagged with: Tags: , , , , , , | Leave a Comment
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