versus Vent-Free Gas Fireplace Products
Gas Log sets are a very convenient replacement for all the
hassles of burning wood: Procuring, chopping, stacking, hauling,
spiders, bugs, sparks, ashes, creosote, chimney fires, cleaning and
waiting for the embers to die down before going to bed, to name a
few. Gas logs sets, whether vented or vent-free types, provide
instant on and off, no sparks, ready fuel supply and look good for
the greater proportion of time when a fire is not burning.
While a fireplace should not to be viewed as a primary heat source,
it can be a fine supplemental heater, providing warmth to a
particular room. Additionally, whether vented or vent-free, it
is a great source of emergency heat in the event of a power outage,
as gas log sets derive their power from the pilot light and/or
Vented gas logs, which we first made in 1958, are
much healthier than burning wood, as there are no wood particulates
that can cause irritation. They are designed with a burner that
produces a yellow, smoky, wood-like flame, so they must be used in a
fireplace with a working chimney, one which exhausts all of the
products of combustion. The products of combustion only enter the
living space if the chimney does not work properly, thus the
occupants are unaffected by the by-products of the gas log during
normal use. Unfortunately, most fireplace designs, while being
efficient in exhausting the combustion products, are very inefficient
as heaters, as much of the heat goes up the chimney rather than into
the room. That led to the development of vent-free set.
1994, Rasmussen became the sixth US manufacturer to make a vent-free
gas log set. Since then, we have created a variety of vent-free
fireplace products, including our Chillbuster line with many styles
of logs and burner arrangements; CoalFire coal basket fires for use
in smaller Victorian and coal fireplaces; and the Alterna VF line of
contemporary gas fires, which include the FireBalls, FireShapes,
FireStones and Fire Glitter. Rasmussen has served on
technical and sub-committees that write and revise the national
standard, ANSI Z1.11.2, to which all vent-free heaters are certified,
and an active member of the Vent-free Gas Products Alliance, our
industry group that is committed to developing and maintaining
markets for vent-free heaters.
consider the following additional factors when deciding between
vented pan burner pan burner and heat-effect gas log sets:
and ALTERNA VF: These sets are
designed, certified and manufactured by Rasmussen to two nationally
recognized consensus standards: ANSI Z21.11.2 Unvented Heaters and
Z21.60 Decorative Gas Appliances. This permits our Chillbuster
Heat-Effect Gas Log Sets and ALTERNA VF Vent-Free Contemporary Gas
Fires to be sold and used in any jurisdiction, regardless of their
position on vent-free use or the position of the chimney damper.
Rasmussen only sells safe products and has been doing so for over
100 years. You enhance and ensure the safety of the product by
properly installing and operating it in accordance with the
instruction manual and applicable codes and ordinances. All
heat-effect gas heaters are equipped with oxygen depletions sensors
(ODS) and safety control valves to shut down the unit in case of
unhealthful oxygen levels or in the event of an interruption in gas
supply or flameout. Vented pan burner sets may be ordered with
safety control valves to shut down the unit in the event of an
interruption in gas supply or flameout.
Heat-effect sets are the best products if you desire a supplemental
and/or emergency heat source for the room in which the fireplace is
located. Since the damper may be closed, there is no heat loss up
the chimney. Please note that heat-effect heaters, like all gas
burning appliances, require fresh air for proper combustion and
customer satisfaction. With heat-effect heaters used in the
vent-free mode, the products of combustion vent into the living
space; with vented pan burner gas logs, the products of combustion
vent up the chimney. Some people are more sensitive to the natural
odor associated with the burning of gas, which can be exacerbated
with a lack of adequate fresh air in heat-effect applications.
INFORMATION about “Partially Vented” or “Reduced Vent” Gas
few manufacturers of gas log sets have introduced gas log sets that
to allow the consumer to close the damper to a minimum opening while
enjoying rich, yellow flames and more heat in the room. The basis
for their claim is a chart in the National Fuel Gas Code that
specifies minimum venting area based on BTUs consumed. The
manufacturers reduced the BTU use from their standard fully vented
gas log sets to a point where the chart allows for a smaller damper
opening, which would keep more of the heat in the room. The
PROBLEM with these sets is that they
all produce soot
and the soot is either going to go up the chimney or out into the
room. The market experience is that the specified “reduced vent”
openings are not sufficient to always exhaust all of the products of
combustion up the chimney, therefore putting soot into the living
space (which can be harmful to health and furnishings). The
only TRUE SOLUTION for someone
who wants to close the damper to a setting less than full open is to
use a HEAT EFFECT gas log set (such as a CHILLBUSTER) that has been
certified to ANSI Z21.11.2 Unvented Heater Standard, since these sets
are not permitted to produce any
"Beauty is in the eyes of the beholder." Rasmussen
manufactures what we consider to be the best looking vented pan
burner and heat-effect gas log sets available. The national standard
for vent-free heaters is very restrictive in ways that limit the
flame appearance (40,000 BTU/hour maximum input; lowest level of
carbon monoxide allowed of any gas burning appliance, no carbon
(soot) formation). The flame characteristics of a vented pan burner
pan burner set are fuller (more BTUs) and more wood-like in
appearance. Since the yellow, smoky flame produces carbon (soot),
and the standards to which these sets are certified allow more carbon
monoxide than heat-effect sets, the damper must be open when
operating a vented pan burner pan burner set. Since most fireplaces
are very inefficient with the damper open, much of the heat is lost
up the chimney. However, the ceramic logs radiate some heat into the
room, as do the burning embers. Additionally, one gets a warm
feeling from the presence of the flame itself.
Heat-effect gas log sets are not permitted to soot by the vent-free
standard to which they are certified. This makes them well suited
for “smoking” fireplaces (those that do not draw or vent
properly). Vented pan burner gas logs sets are designed to burn with
a yellow smoky flame that produces soot. Vented pan burner sets
require that the chimney flue exhaust al of the products of
combustion up the chimney, otherwise the soot will enter into the
living space. This is the trade-off for the rich, luminous flame.
Size Selection: Heat-effect gas
log sets are available in 18-, 24- and 30-inch sizes with various log
appearances and burner styles. Vented pan burner log sets are
available in sizes ranging from 12- to 96-inches, with custom sets
available for large and unusual fireplaces. We currently offer 14
styles of vented pan burner log sets as well as many contemporary
styles, such as FireBalls, FireShapes, FireStones and FireGlitter.
Heat-effect gas log heaters (like CHILLBUSTER) give you the best
heat value from your gas dollar spent. They also give you
flexibility of venting, as you can safely use them with no or little
damper opening, as desired and permitted by local jurisdiction. The
vented pan burner set better approximates the aesthetics of a wood
fire. There are many more size, burner style and control options for
vented sets, as well as the ability to have custom solutions for
large and unusual fireplaces. The choice is yours based on your
needs and desires.
Information about Vent-Free Sets
ANSI Z21.11.2 (the national
Unvented Heater standard to which all vent-free products are
certified) is the most restrictive of all gas appliance standards,
which allows the least amount of Carbon Monoxide (CO) (200 ppm air
free) of any gas burning appliance. By contrast, the standard
for a kitchen range, which is also an unvented appliance, allows up
to 800 ppm air free. In addition to the vent-free standard, all
Rasmussen vent-free sets are certified to the vented decorative
standard (ANSI Z21.60), which allows you to use the damper closed,
open or anywhere in between, depending on your preference and local
ANSI Z21.11.2 standard also requires that all vent-free heaters be
equipped with an Oxygen Depletion Sensor (ODS). An ODS is a
system that includes a quick-acting thermocouple and a calibrated
pilot. The pilot becomes unstable at lowered levels of oxygen,
causing the thermocouple to close down the flow of gas through the
valve to the burner. Normal room air contains 20.9% oxygen. Death or
serious injury occurs at oxygen levels of about 15%. An ODS is
required by the standard to shut down the system by 18.0% oxygen.
the ANSI standard, vent-free gas log sets must be designed so that
they do not produce soot.
vent-free sets use a state-of-the-art opposed-louver lanced-port
burner. This type of burner is very forgiving when operated
under adverse conditions, such as improper log placement or drafts.
Such conditions result in the flame impinging on the logs, which
cause soot from our competitors' punched-port burners, but operate
clean with the Rasmussen burners.
certification testing is extremely rigorous. We are subject to
periodic unannounced inspections by our certification agency.
Rasmussen, unlike most of our competitors, gas tests every vent-free
burner to ensure gas tightness of all fittings and proper operation.
gas log sets, like all gas burning appliances (including vented gas
log sets), require fresh air for proper combustion and customer
satisfaction. When used without adequate fresh air, such as in
tightly constructed homes or in homes in which all avenues of air
infiltration are sealed off, certain odors can become a nuisance.
The sources of these odors are impurities in the air in the living
space (such as cigarette smoke, pet hairs, off-gassing from paint,
carpets, laminates, glues textiles, etc.) or from the natural odor
associated with the burning of gas.
vapor is a natural product of combustion. Without adequate
fresh air, it can build up to the point of being noticeable and
unpleasant. It can mix with impurities from other sources to
cause a brown film on walls and windows.
you can see, fresh air is important for a satisfactory experience
with a vent-free heater. If you have any doubt, you should use
either a vented set with the damper fully open, or a vent-free set
with the damper cracked open to permit some of the products of
combustion to exhaust. One big advantage of the vent-free sets
is that you can change the damper position to help strike the best
balance between heat and indoor air quality issues.
40,000 BTU/hour maximum gas input for vent-free heaters restricts the
largest width of a set to 30-inches.
the vent-free, the log stacks are set in their log placement to
provide the best combustion. You do not have the flame playing
off of the logs like that of vented sets, where the logs are loose
and can be arranged as desired.
Life is full of trade-offs.
The limitations set by ANSI Z21.11.2 allow you to operate the set
with the damper closed, thus virtually eliminating the heat loss up
the chimney. But, they just don't look as good as the vented
sets. But if you choose the fuller flame and more random and
full log stacks of the vented sets, you lose much of the heat from
the requirement that the damper be wide open when burning.