Correct and older furnaces, both oil and gas required chimneys. New
furnaces both oil and gas have the option of direct venting though oil
furnaces use metal pipes for their vents, not PVC. That difference is of
no relevance to cost or operation though.
In practice it is a 4 inch double walled galvanized metal pipe.
When we use the word chimney, it brings negative connotations of a brick
lined rectangular box 24 ore more inches wide, 6 or more inches deep.
With a house that is tight, below 4 ACH, yes you need a separate pipe to
bring in fresh combustion air. This pipe is usually PVC.
What is the efficiency rating (AFUE) for these "modern efficient oil furnaces?"
natural gas furnace is about 96% efficient (AFUE), meaning that about 96% of the
energy in the gas becomes actual heat in my house. How does your "efficient oil
Well, no, it means that the furnace sends 96% of the energy in the gas
to it's output as heat, whether that actually becomes heat in your home
is dependent on other factors. A good oil fired boiler I looked at was
86.8%, I don't have numbers handy for oil furnaces at the moment. Again,
there are multiple reasons to choose oil over nat. gas.
Not true. Heat that goes up the chimney or out the exhaust is not included in
would make AFUE pretty pointless if the heat being measured in its rating wasn't
go into the distribution system. (I am assuming that all heat in the duct
system goes to
the house and that you aren't running ducts outside, through an ice cellar, or
"The Annual Fuel Utilization Efficiency (AFUE) measures the amount of fuel
space heat in proportion to the amount of fuel entering the furnace. This is
expressed as a percentage. Energy Star labeled furnaces must meet or exceed 90%
energy-efficiency ratings." http://www.waptac.org/sp.asp?idh41
I was referring to the losses after the furnaces heat output, not the
Bad assumptions as well since a large percentage of furnaces and related
duct work travel through unconditioned space. Horizontal configuration
gas furnaces in particular often end up in cold attics.
Yes? And? As I said there are a lot of losses after the furnace output
and gas furnaces often end up in icy attics where oil furnaces almost
In almost ALL communities where natural gas service is available, local
codes do NOT permit the exhaust gas from the natural gas furnace to
share a common flue with a fireplace, and such installations, in almost
cases REQUIRE a cap.
Fireplace chimney is NOT the same as gas furnace chimney, DANGEROUS to
put the two together.
Who said anything about a fireplace chimney? There are a tremendous
number of multi flue chimneys out there that do not have screen caps on
any of the flues. Separate flues for fireplace and furnace.
Again the fact that oil combustion products other than CO are far more
human detectable than those of gas means that that incident may not have
resulted in deaths had it been an oil furnace. The nasty building fumes
would have very likely driven the occupants out before a lethal CO
exposure could occur.
False. Modern oil and gas furnaces produce comparable amounts of
emissions. The exact composition is different, but the overall pollution
is the same (the EPA and DOE have studies that confirm this if you want
Different emission components have different levels of human
detectability and oil emissions are more detectable than gas emissions.
In the case of both oil and gas, they don't produce a lot of CO unless
the combustion adjustments are quite a bit off. When the adjustments are
off the oil becomes even more detectable than the gas when the
adjustments are off.
None handy, just personal experience with the exhaust of both under both
proper combustion and improper combustion conditions. Neither is very
detectable under proper combustion, but neither produces much CO then
either. Under improper combustion the oil exhaust is far more noticeable
as it produces both fine particulates (soot) and vaporized hydrocarbons.
I did, before I moved. I do not at present because I have no combustion
appliances at present (electric).
Now, I'd love to see the supporting data for the claim that modern gas
and oil furnaces produce the same amount of pollution. Why do you
think many cities have replaced diesel bus fleets with ones that run
natural gas if burning oil is just as clean? Natural gas produces only
water and CO2. And nat gas even produces a third less CO2 than
burning oil. Burning oil, in addition to the above, produces
particulates, nitrous oxide, and sulfates.
The poster is right. First, you proclaim the smell produced by burning
oil to be a virtue, because it may save you from dying from CO. . Then
you claim oil heat is as clean as nat gas. Did you ever see an oil
based appliance of any kind vented into a home? Yet millions of nat
gas kitchen stoves work exactly that way. Gee, I wonder why?
A whopping total of 28 people a year die in the US from CO from natural
gas heat systems period. I'd like to see any real world evidence that
oil heat systems are any safer overall. Nat gas continues to increase
in market share, while oil heat is now down to 4% of new homes. If
it's so unsafe and unreliable, why is that?
Try looking at the EPA and DOE sites.
You don't read well do you? I indicated that both are not very
detectable when combustion adjustments are proper and neither produces
much CO under those conditions either. It is when combustion adjustments
are out of whack that a lot of CO is produced and it is also under those
abnormal conditions that oil exhaust is much more detectable than gas
Not for the reasons you apparently think.
Indeed they are. CO is not the only way a nat. gas heating system can
kill you. Add in the number of deaths from gas explosions to the CO
deaths and then compare to oil. Then compare the number of injuries from
gas explosions to the number of injuries from oil explosions. Then tell
me which is safer.
1) Consumer ignorance - Believing nat. gas somehow avoids buying foreign
energy. They apparently are not aware of the LNG super tankers
delivering foreign LNG just like oil tankers delivering foreign oil.
Both nat. gas and oil are produced in the US and both are also imported
from foreign sources.
2) Marketing - Some deceptive as in the case of the short lived "safe"
in one gas suppliers advertising. Deceptive price comparisons that do
not account for service charges during periods of no use. Deceptive
claims of reliability of oil fired equipment. Deceptive claims about the
cleanliness of oil burners. Deceptive comparisons of "upgrade" costs to
low end gas equipment with service lives in single digit years.
I'll also note that that market share is rather slanted to southern
1) There are minimal heating requirements which means consumers can get
low end gas systems to last longer.
2) Gas companies cover larger service areas in large part due to lower
installation costs vs. the northern states with more rock to cut and
3) Gas companies market more since they generate more profits from
service charges during the long hot months where they have to supply
4) The southern states have been having a huge housing boom as a whole
due to lower construction costs and most tract housing gets gas systems
not because they are better in any way, but simply because the cheapest
low service life units available are in gas which means more profits for
the developers and replacement costs for the consumer a short time down
What is the number of deaths from natural gas versus oil? Can you show us the
numbers or is
this just a FUD campaign?
The amount and proportion of natural gas that is imported to the USA is tiny
oil. Much of the imported natural gas comes from right here in North America,
areas of the world like the Middle East.
Which supplier are you talking about? What is the definition of "safe?"
Service charges? Like the $4/month minimum billing fee that I pay for my
service? My electric company charges more than that so your argument is
service too. Even including that fee (which includes service for my hot water
grill, stove, and dryer) I'm still way ahead with gas, and I have a very
Huh? What is your source of this claim?
You said they are a monopoly. Why would they need to market? I hear a lot of
by oil dealers, or the collective oil dealers, operating as one.
I don't have specifics handy, but I'm sure you can find them with a
They are out there on one of the government sites. Certainly the ratio
of hundreds of gas explosions to zero oil explosions should be pretty
obvious. Someone was killed in a gas explosion at a motel just a month
ago, and no, I don't count the deliberate gas explosion suicide in NYC.
How does it compare to the 50% or so of oil that we import? The general
public seems to think we get 99% of our oil from the middle east which
certainly isn't true.
It was Connecticut Natural Gas as I recall. I don't know the details
exactly, but their "Clean, Safe, Dependable Natural Gas" campaign only
lasted like six months before mysteriously becoming the "Clean,
Dependable Natural Gas" campaign.
My definition of safe would be free from threat of catastrophic and
potentially fatal failures i.e. explosions.
Electric service is rarely without some usage. With gas service it is
not uncommon to have periods of zero use. Certainly this is not true in
every case, but again, this is only one of many reasons to not use nat.
gas, not the sole reason.
When the low end gas furnace is only required to operate from November -
February it will clearly have a longer service life than the same unit
required to operate from September to April.
Check with any gas company for the cost of extending gas service to your
street in say CT vs. OK for comparable distances.
When I was in CT I watched the town blast for three days just in the few
hundred foot stretch in front of my house to install storm drains. I
also watched weeks of blasting when widening the main road down the
street. I've watched major construction in my new location in TX as well
and there was no blasting required.
I've also dug a 650' trench in CT for conduit and an 80' trench in TX
for conduit and I can assure you the TX trench went far faster and
easier per foot and required much smaller equipment than the CT trench.
They market to get you locked into their nat. gas monopoly. They market
to those that use other energy sources.
No handy online reference, but a low end gas furnace installation is at
least a thousand dollars less than a low end oil furnace installation.
The low end gas unit will also have a service life expectancy about half
of the oil unit. Both will be blow the service life of the average units
in each class, but the oil still last longer there as well though the
ratio is not as extreme.
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