Are you considering having an open masonry fireplace built in your home? STOP! WAIT! Do some research or talk to someone about their love-hate (mostly hate) relationship with their open fireplace. (This article also applies to you…frustrated open fireplace owners.) We’ve heard the complaints. The builders, contractors, and masons have heard the complaints. Don’t despair; we also have the solution.
A couple hundred years ago a traditional masonry fireplace was state-of-the-art design; function and beauty wrapped up in a neat little array of bricks and mortar. Today’s energy efficient homes are tightly constructed, well insulated around windows and doors, and have the latest in advanced heating equipment. Yet, the past is alluring, and many homeowners make the mistake of installing an open-hearth fireplace smack dab in the middle of tens of thousands of dollars worth of 21st century technology. Seems like a conflict of interest, right? They quickly discover that their quaint and traditional open fireplace is inefficient, filthy, smoky, requires an inconvenient amount of wood for the small amount of heat output, stinks, blows cold air into their house, and sets off the smoke alarm. Then they wonder why.
Air wants to flow to zones of lower pressure.
Most homes built today have the fireplace against an exterior wall on the ground floor. Whether or not the chase is insulated in this position it’s likely that the outside cold air will decrease the temperature of the flue. Meanwhile, the air inside the house, which is warmer than the outside air, rises. So, the air pressure high in the house is slightly positive, which leaves the pressure on the ground floor slightly negative. When the temperature of the flue falls below the temperature of the bottom floor that cold air will get sucked into the home.
Modern homes also come equipped with powerful exhaust fans such as dryer vents, kitchen ranges, and negative pressure ventilation systems. These fans will quickly depressurize a house…again causing air to flow down the chimney into the home.
Even the simple physics of operating an open fireplace in a home today just don’t add up. Today’s homes can’t tolerate more than 200 cubic feet per minute (cfm) of expelled air without becoming depressurized. An open-hearth fireplace will easily consume 200 – 600 cfm depending on the size of the fire. So, here again, we have a positive outside air pressure combating a negative pressure home.
In all these examples we see what is called “back-drafting.” The house is acting as a better chimney than the chimney itself. It explains why there’s cold air emanating from the fireplace and why you get a face full of smoke when you go to light it. Combustion also produces toxic gases such as carbon monoxide, sulfur dioxide, nitrogen dioxide and methane. You know where I’m going with this, right? When your open fireplace is back drafting those toxic gases are being pumped right into your living space. Excuse the sarcasm, but that’s probably not the healthiest stuff to be breathing in.
There are options though. Many wood fireplaces and inserts can be installed to look like a traditional masonry fireplace. Lopi manufactures highly efficient, EPA certified models. You don’t have to sacrifice design for functionality or vice versa. Our units have aesthetic appeal while delivering an impressive heat output to your home. The Freedom Insert shown in the photo below is the most efficient large insert on the market. You can choose between a flush mount installation or extend it on to the hearth to take advantage of the cooktop surface. The unit features a built-in convection chamber that circulates and distributes warm air throughout your home, and a bypass damper for smokeless startup and reloading. Click on the photo to review Lopi’s entire line-up of energy efficient wood inserts.
Your 21st century home deserves a 21st century fireplace. Do the research. Choose the wood fireplace or insert that’s right for you and make sure to have it installed by a certified specialty hearth retailer. Visit www.lopistoves.com to find a dealer near you and to learn more about our wood fireplaces.
To learn more about heating with wood go to www.woodheat.org.