Bruce W. Maki, Editor.
In the fall of 2002, about one month into the heating
season, our old oil furnace began acting up. I knew it needed
to have the burner adjusted and the combustion chamber
cleaned, at the very least. I called our usual oil furnace
service company, and I was surprised to discover that the
annual service fee had gone from $70 to $115. I called some
other places and found similar rates. I also found that some
heating companies had discontinued servicing oil furnaces
because their liability insurance rates had increased
dramatically, and the number of oil furnaces was declining.
I could read the writing on the wall: The dinosaurs were
going extinct. Living out in the country, natural gas is not
available. I've noticed over the years that new houses in
these rural areas always have propane tanks. I made some more
calls and was pleasantly surprised at how competitive the
propane supply industry was. All of the suppliers had special
low rates to entice new customers to sign up. They install the
tank and supply line for practically nothing, and then often
give big discounts on your first fill up.
I began to understand why oil furnaces were losing
popularity. Many years ago, oil was the fuel of choice for
people who didn't have natural gas service. But oil is a dirty
fuel. I would call it a filthy fuel. When I removed the
back access panel on the oil furnace I couldn't believe the
amount of soot in the heat exchanger. The bottom one-third of
the passageways were blocked. I literally dug out what looked
like yellow bricks but were actually blocks of sulfur.
Fuel oil (and diesel fuel, which is virtually identical)
has a very high sulfur content. I read somewhere that the
sulfur content is around 3,000 parts per million, which would
be 0.3%. For an impurity, that is a very high concentration.
Why should the homeowner deal with sulfur removal (with an
annual furnace cleaning) when the petroleum refinery can
With an oil furnace an annual cleaning and service call is
truly necessary, because the soot needs to be removed from the
heat exchanger. Also, the oil spray nozzle should to be
replaced and the air-fuel ratio adjusted to minimize soot
buildup. As soon as the soot builds up, it begins to restrict
the flow of combustion gases. If this gets bad enough, it can
cause the furnace to stop functioning, or worse, can send
combustion gases into the house.
What a headache! Gas and propane furnaces do not have the
same maintenance needs as oil furnaces. Sure, the air filter
needs to be replaced monthly, and it's a good idea to vacuum
the dust off the blower every year (I just use a shop vac and
a clean, dry paint brush), but most of these furnaces do not
need annual cleaning of the burner or combustion chamber.
True, gas and propane burners can get a small amount of soot
buildup, but I've seen them go 10 or 20 years with nothing
more than a wisp of ash.
Consider this: With an oil furnace the annual maintenance
expense, in my area, is going to be about $115 more
than a gas or propane furnace. If we had to park some money in
the bank, so that it would generate enough interest to cover
the annual service, it would be a chunk of change. Those
readers with some finance background might see where I'm going
with this: The present value of that perpetual stream
of $115 annual payments is quite large. Given the low interest
rates today, it would take an investment of $2,000 to $3,000
to generate the $115 annual cash needed.
What's the point of this? It's part of the financial
decision to kill the oil furnace and install a new propane
furnace. Reducing our annual maintenance costs by $115 is
equivalent to having an extra $2,000 in cash right now. When I
talked to a local plumbing and heating outfit and heard that
new gas/propane furnaces can be had for as little as $800, I
The other problem: When we re-shingled the roof we
noticed that the chimney was messed up. I looked down the
chimney and I discovered that there was no fire-brick lining
or terra-cotta flue tile. Just plain brick. That's not right.
Above the roof line, most of the mortar had disintegrated. I
re-packed the joints with new mortar and crossed my fingers. I
talked to one chimney repair specialist, and they wanted
$2,700 to drop a stainless steel flue liner down the 36-foot
tall chimney. Just to keep the house eligible for an oil
burning furnace. When the oil furnace puked out, I was not
We solved our problems by having a high-efficiency gas
furnace installed, which vents through the wall with PVC pipe.
Being autumn, the contractor was so busy he had trouble
getting a quote to us, so we asked them to just bill us for
time and materials. I would be there to help out, help move
the furnace into the basement and do any other work needed.
Since we installed the new furnace in a different location
than the old one (we were no longer constrained by the chimney
location) we changed much of the ducting. We provided the
supply and return ducting and re-routed the electrical supply.
Following the guidance of the furnace installer, I connected
the condensate drain pump to a nearby plumbing drain line. The
installer only had to connect to the ducts with some minor
sheet metal work, install the combustion air and vent piping,
connect the propane line, convert the gas valve from natural
gas to propane, and do the tuning. In all, he had 8 or 9 hours
of labor, at $60 an hour, and the materials amounted about
$2,000. For less than the cost of the chimney repair, we
had circumvented the need for a chimney, escaped the $115
annual service charge, and got a new reliable furnace.
Granted, our costs were low because we did a considerable
amount of the work ourselves.
This old house had propane many years ago, for a stove and
dryer. But the lines were copper, and too small to provide
propane to a furnace. Copper is no longer allowed for lines
that run through floors or walls, so we replaced all the lines
with 3/4" and 1/2" black iron pipe. This cost a
couple of hundred bucks, just for materials, and took several
days. We also pressure tested the replacement installation
with 30 PSI air pressure for several days (rather than the 30
minutes as required by code) to make sure there were no leaks.
The propane company installed a new 500 gallon tank and ran a
supply line to the house. They also installed a branch line to
the garage, for a future propane heater in the shop. The cost
was minimal, about $150.
We are very pleased now that the sulfur-belching
oil-sucking dinosaur is gone. The new furnace is quieter and
cleaner. Since a gallon of liquid propane has less energy than
fuel oil (about 92,000 BTUs versus about 130,000 BTUs for oil)
the actual annual heating cost may be slightly higher than
with fuel oil. So far, it seems to be about the same, but this
winter has been the coldest I've seen while living in this
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