Heating Your Flue Before Lighting Your Fire

Top tip: You can’t have a fire with a cold flue. Or rather, you can, but that fire will probably be quite smoky and difficult to sustain — and no one wants that. In our previous blog on “How to Get a Good Fire Going”, we touched on the importance of prepping your flue before starting your fire.  Prepping your flue is crucial to establishing a good draft in your chimney system. We want to talk more in-depth about this preparation process to help ensure that you have a safe and pleasant fireplace fire experience.

Why Do I Need to Preheat My Flue?

Preheating your flue every time you light a fire is crucial to ensuring that air is cycling properly in your chimney system. When you are not operating your fireplace, the chimney is full of cold air (especially during the cold and damp winter months). This cold air is very heavy and essentially acts as a plug in your chimney. If you were to just light your fire without preheating the flue, the initial heat and smoke of the fire would be too weak to push the cold air out. The smoke will just take the path of least resistance and escape into your home. Instead, you want to warm up the flue first to push the heavy cold air out and start a draft cycle that will pull the smoke up and out of the chimney. Because, science.

So How Do I Do It?

The first step is to make sure that your damper is all the way open. Once you are certain of this, get set up to start your fire. Before you do so though, take a piece of newspaper (preferably paper without color or gloss) and roll it up. This newspaper will serve as a sort of “torch” that you will use to warm the flue. Once you have made a couple of these “torches,” light them and hold them high up in the flue area. The heat from the newspapers will be strong enough to push out the heavy cold air and establish a draft. If this method doesn’t work well for you, you can leave the damper open for about a half hour and allow the warm air in the room to push the cold air out. However, this method is less energy efficient than using the newspaper. No matter which method you use, you want to be sure that you feel the flow of air reversing and the warm air being sucked up into the chimney. Then, you are ready to build and enjoy your fire.

If you are preheating your flue but still experiencing smoky fires, there may be some obstructions or other issues in your chimney. It critical to have your chimney swept and inspected by professionals to avoid problems like these and other serious hazards, such as flue-fires or carbon monoxide leaks. Please don’t hesitate to give your certified Chimney Outfitters a call. We want you to enjoy a functional and safe fireplace.