Interesting facts:

• Chimney sweeps in the 1800s were frequently children who had been sold into indentured servitude.  They were often afraid of their job, so their master would sometimes “light a fire under them” to force them up through the flue cleaning.  Hence the phrase.  
• The National Association of Realtors estimates that a fireplace/chimney adds about $12,000 to the value of a home
• Santa Claus first came down a chimney in a poem by Clement Clark Moore in 1823
• A lively fire in the fireplace can easily create temperatures in the flue of 2000 degrees or more.  
• A cord of wood is a stack of wood 4’x8’x8’.  Like a heavy pickup truck load.  (A useful factoid for your next lumberjack cocktail party).

Tips:

• One of the biggest dangers that occur in a chimney is the buildup of creosote–a tar-like substance that sticks to the side of the flue when wood is burned.  It is flammable, and can pose a real hazard if it is allowed to buildup.
• Another big danger is if the flue gets a crack or gap in it.  That can allow the superheated air or poisonous gases into the house instead of going up and out.  Both those things are bad.  
• An easy solution to both is an annual chimney sweep and inspection.  This usually costs less than $150, and takes less than an hour, but will make sure you are safe from these risks.  

Parts of a Fireplace/Chimney:

• Hearth   The part on floor level that you can sit on.  Usually brick or tile.

• Firebox   The boxy area where all the fire is.  Was it that obvious?

• Damper   The flap (usually metal) that closes to prevent animals or cold air from coming in the flue, and then causes you to curse and your smoke alarm to go off when you forget to open it on the first night you use the fireplace.

• Mantel   The ledge above the firebox in the room where the stockings are all hung with care

• Smoke Chamber   The area above the damper that collects the smoke to suck it out as the hot air rises through the flue.  Also, the janitor’s closet in the basement at high school where the cool seniors would go between class.

• Flue   The long tube that takes the smoke and hot gasses up and out of the house.  A good chimney sweep inspects this with a camera to check for cracks or voids in the joints.  

• Mortar Crown  The cap on a brick chimney that protects the chimney from getting ice or water in it.  There’s a pretty good chance yours is cracked or falling apart, and if you let it stay that way, it will turn a $400 repair into an $8000 repair in a few years when the chimney starts falling apart.

So, what’s the moral of the story?  Use the fireplace, it is great.  But just get it cleaned–preferably in the spring.