How often should I have my chimney cleaned?
Have your chimney
checked every year, as recommended by the National
Fire Protection Agency, to make sure the chimney can
do its job to properly vent hot, toxic gases and
carbon monoxide from the heating system to the
outdoors. Temperatures inside the chimney often
exceed 2000 degrees.
What causes a chimney
fire?
The cause of most
chimney fires is creosote which is a by-product
resulting from the incomplete combustion of wood. It
accumulates on the sides of your chimney as a liquid
and later condenses into a solid. As it builds up it
not only blocks the flue, but can ignite into a
roaring fire. These fires can be prevented by making
sure your flue is lined and in good repair, by
having it inspected and cleaned regularly by a
professional and by learning how to build fires that
reduce the build-up of creosote.
How can having a
chimney cap protect my fireplace?
A chimney cap on top
of your flue can save you money in the long run.
They keep out moisture which can damage and erode
the masonry and steel chimneys. A long lasting
chimney cap also keeps out debris and helps prevent
birds, animals, and insects from nesting in your
chimney.
Why does my fireplace
smell?
Rain, moisture, or
high humidity (not uncommon to our area) most often
causes this. Having your chimney cleaned after the
wood burning season will help eliminate the smell
your fireplace may emit during the humid and hot
summer days.
What is the best wood
to burn as firewood?
Burn only
well-seasoned hardwoods, such as Oak. This helps
reduce creosote build-up in your wood-burning
chimney system. You can burn other softer wood also,
as long as it is split and dried long enough. The
most important thing to remember is to burn dry
wood.
How can I clean the
brick around my fireplace?
Mix one ounce of soap
and one ounce of table salt with enough water to
make a cream. Rub the moisture into the brick
surface with a cloth, allowing it to dry at least
ten minutes. Then complete your cleaning job by
removing it with a stiff brush.
Why do I need to know
what a freight train sounds like?
If it sounds like one
is coming down your chimney, then you are probably
experiencing a CHIMNEY FIRE! Not our idea of
something to look forward to when you are all
'snuggled in bed on a cold winter's night.
Can a fireplace behave itself in
a tight house?
Yes, but open fireplaces give all
fireplaces a bad name
Talk about a clash of
technologies: In a house that is to be
tightly-constructed and well-insulated so it will be
cozy and easy to heat, the homebuyers want to have a
traditional open fireplace, a device whose design
was state-of-the-art a couple of centuries ago. Once
built, this new house and old fireplace will not
coexist without conflict and the owners might regret
reaching back in history to select their fireplace.
To perform reliably
in a modern house, the unruly traditional fireplace
must be tamed by some new technology, but it need
not lose the essential qualities that have always
compelled us to gather around the hearth.
Declaring my bias, I
freely admit my enthusiasm for fireplaces and think
that every house needs a hearth to be complete. A
fire burns on my hearth all winter and I never tire
of watching the flames and being within range of
their warmth.
That said, I also
think the traditional open fireplace is headed for
extinction and I, for one, won't shed a tear at its
passing. The end will come because the open
fireplace is an antique technology that is
incompatible with modern housing. It is wasteful by
temperament, and through its gluttonous appetite for
fuel and air, it scoffs at the ideas of energy
conservation and environmental correctness.
If you build a
standard house using the latest in materials and
techniques, its tight skin will not leak enough to
supply the air demands of an open fireplace. The
problem is not with the house, but with the
anachronistic fireplace.
Strong opinions,
often colored by myth and misinformation, usually
surround discussions of fireplaces. So, to avoid any
misunderstanding, allow me to propose this basic
principle: A fireplace should work well all the time
and never screw up in a big way; should not belch
acridly during a party, should not set off the smoke
detectors at 2:30 in the morning, and should not
stink and gush cold air when no fire burns. And
further, given the advanced state of construction
and fireplace technology, a builder should be able
to confidently guarantee to the homebuyer that the
fireplace will perform properly.
It is not much to
ask, really, that a fireplace work properly, no more
than we ask of most other building components. Yet,
complaints about nuisance fireplaces are among the
most common call-backs in the building industry.
Despite the voodoo preached by proponents of certain
variations on the theme, there is nothing magical
about fireplace design. For example, here is a
pretty reliable rule of thumb: the more air the
fireplace demands for normal operation, the more
susceptible it is to spillage and back drafting.
If you place the fire
on the room side of a flow restriction, like a
throat damper, you need strong draft and high flow
up the chimney to keep smoke from spilling into the
room. An open fireplace consumes between 200 and 600
cubic feet per minute (cfm) of room air—more if it
is a big fireplace with a big, big fire. Tightly
built houses cannot tolerate a 200 cfm exhaust flow
without getting meaningfully depressurized, so
there's a problem right away.
If a home buyer
rigidly demanded an open fireplace, it could be made
to work if you threw enough money and horsepower at
the problem. A chimney top fan could be installed at
considerable cost, but it could severely
depressurize the house in its attempt to flow enough
air to prevent smoke spillage from the fireplace,
and would likely back draft a conventional gas
furnace or water heater. Alternatively, a
high-volume, fan forced, pre-heated outdoor make-up
air system could be designed and installed. Just
before lighting the fireplace, the user would turn
on the make-up air fan, pressurizing the house and
forcing the necessary flow through the fireplace and
up the chimney. This large-capacity make-up air
system would be complicated because the incoming air
would need tempering by a
thermostatically-controlled electric duct heater of
substantial output. Distributing the air effectively
could also be a challenge. Both options—the chimney
top fan and large make-up air system—are expensive
and both have drawbacks.
There are easier ways
to tame the fireplace. When you place the fire
behind the main flow restriction, say a glass door
assembly, you can get away with lower flow rates and
draft levels without smoke spillage. With doors,
even a set of leaky bi-fold doors, the flow rate
drops by three-quarters to 50 to 150 cfm, depending
on flue size, fire size and door leakage. The
barrier between the fire and the room formed by the
doors makes the fireplace more spillage-resistant by
a huge margin. The doors don't make this fire place
an efficient heater, just less of a nuisance.
Some people claim
that glass doors spoil a fireplace. (Do they mean in
the same way electric lights spoiled the pleasure of
reading by candle light? Or the way shock absorbers
on cars took away the feel of the road?) In reality,
at least a spark screen is needed to prevent damage
to rugs, floors and furniture when the
characteristic crackle of the fire spits glowing
bits from the hearth. True, glass doors do block out
most of the sound of the fire, which is just fine
for those of us who find the crackle only makes them
apprehensive about those glowing bits. Given the
choice of looking through a wire mesh screen or
clear glass, I'll take the glass.
Beyond the open
fireplace at 400 cfm average air demand and the
fireplace with doors at 100 cfm, there is a third
category in this descending order of air demand.
Call it a controlled-combustion fireplace. It has
doors with gaskets and it manages both the amount
and location of combustion air it admits. By
limiting the flow of air to an amount closer to that
needed for combustion of the wood, the demand falls
by three-quarters again to 15 to 30 cfm. Within this
category, I would include all the factory-built
fireplaces that meet the Environmental Protection
Agency (EPA) emission limits for wood heaters, as
well as massive heat-storage units like masonry
heaters, Russian fireplaces and their ilk. There are
also many controlled-combustion fireplaces that are
EPA exempt, which, because they are fairly modest
consumers of room air, can function well in tight
houses.
Not incidentally, a
fireplace's consumption of room air directly affects
its efficiency, that is, how much of the energy
contained in the logs is transferred as cozy warmth
to the room. Because they suck up so much room air,
open fireplaces deliver between zero and 20 per cent
net efficiency. The low efficiency results from the
house furnace working so hard to heat up the outside
air that must come in to replace air exhausted by
the fireplace. The colder the weather, the lower
the delivered efficiency from an open fireplace. A
fireplace with doors can deliver between 10 and 30
per cent efficiency, depending on whether it has a
heat exchanger that works, but this is still lousy
efficiency by modern standards. A fireplace that
uses current technology, one that is EPA certified
for low emissions, for example, will deliver between
60 and 70 per cent efficiency. This means a modern
wood burning fireplace is competitive with any other
form of home heating in terms of energy efficiency.
Some housing
technologists recommend that builders avoid using
any heating or hearth appliance that vents through a
chimney and operates on natural draft. This caution
would apply to all wood burning fireplaces because,
with current technology, they must be vented through
a vertical chimney. While I'm sure such advice is
well-intentioned, if adopted, it would mean the
elimination the natural hearth from every new house.
Home buyers could not enjoy the comfort and quality
of a well-built modern home while sitting in their
favorite chair in front of a real wood burning
fireplace. They could not stay cozy and comfortable
during an electrical power failure by burning wood
in the fireplace. They would be unable to use this
renewable energy source as one route to
environmental responsibility, but would be forced to
heat with fossil fuels and be locked into a
one-sided relationship with a large energy utility.
If they wanted a hearth, their only option would be
a virtual fireplace burning gas or propane with its
designer flame and mind-numbing sameness. Of course,
gas fireplaces are fine for urban houses and
apartments, but one of the great pleasures of living
on the urban fringe and beyond is to build a real
fire on a beautiful hearth and sit back to enjoy it.
A future of houses
without real fireplaces is not particularly
appealing. Luckily, it's not necessary either. By
matching technologies, it is possible to combine a
modern house with a real fireplace. In specifying a
spillage-resistant fireplace for a well-built house,
the first line of defense is a set of glass doors.
These must have panels of ceramic glass, a miracle
material that won't shatter, but will allow infrared
(heat) radiation into the room.
Better still, select
an EPA certified fireplace or a masonry heater from
a reputable supplier. These units consume very
little room air and can tolerate a modest level of
room depressurization without complaint. They can be
just as beautiful as a traditional open fireplace,
but their manners are so much better.
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