Why is there soot on my walls, ceilings and furnishings and what is this term "candle sooting"?
We're glad you asked!
Many consumers have been blaming soot
deposits on walls, ceilings and furnishings on their new furnace
and heating system. During the last year much research has been
done to scientifically prove the cause.
Candle Sooting
Increased complaints regarding blackened carpets, baseboards,
plastic switch 
plates, kitchen appliances and television screens,
as well as dark lines on ceilings and walls have prompted several
recent investigations. The furnace/air handler is usually blamed.
Upon inspection, the furnaces/air handlers are generally found
to be doing what they were designed to do: pull air into the return,
condition the air, then return the conditioned air to the living
space. Of course, anything in the air will be pulled in and redistributed
through the duct system.
Investigation has shown that soot produced by scented candles;
jar candles and oil candles are the likely cause of the black
stains. In the last 5 years the candle industry has doubled as
demand has increased. Candles are now mass-produced; using what
is suspected to be lower grade waxes and materials that result
in a higher oil content. These candles produce more soot when
burned.
In a test by Engineer Ron Bailey in Palm Beach Gardens, Florida
four candles were burnt for a total of 15 hours. These candles
produced so much soot in the home that testers were forced to
stop for fear of creating too much damage in the house. "We had
significant soot production on the walls, drapes, dishwasher.
Refrigerator, and the air filter."
Factors that Increase Sooting
Bailey explained that there are two issues to consider when looking
at how a candle might soot. "The length, thickness, and strength
of the wick highly influences how a candle burns, and also what
is in the candle wax itself." Today the growing trend is the use
of aromatic candles. Fragrances added to the wax should be specifically
for use in candles. The high temperatures can cause chemicals
to behave differently once burned. "Five percent paraffin wax
is good," said Bailey. "But with many of the candles in stores
today, we find a mixture of materials, including some fragrances
and chemicals can result in a candle that is going to burn dirtier
than expected."
Most filters used in furnaces/air handles are not capable of removing
the ultra fine soot produced by candles. When confronted with
a claim of a furnace/air handler suspected of causing sooting
in home, check first for the use of candles in the home. Check
all candles before you purchase them, if this canšt be done, and
often it is not possible, then once the candle has been light
hold a clean white paper above the flame 3"-5" and if soot deposits
on the paper extinguish the candle and do not use it indoors.
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