How is 80% AFUE achieved
 

Compared to a 20 year old furnace how much does each design improvement
increase AFUE:

Draft inducer fan
Ignitor vs pilot
Faster fan startup (is this due to the draft inducer)
Hx design chages?
Anything else?

"HL" wrote in message
news:tNurd.223772$df2.120623@edtnps89...
Compared to a 20 year old furnace how much does each design improvement
increase AFUE:

Draft inducer fan
Ignitor vs pilot
Faster fan startup (is this due to the draft inducer)
Hx design chages?
Anything else?



Yes.

The biggest improvement, IMO, is the ignition vs. the standing pilot.

"HeatMan" wrote in message
.. .

"HL" wrote in message
news:tNurd.223772$df2.120623@edtnps89...
Compared to a 20 year old furnace how much does each design improvement
increase AFUE:

Draft inducer fan
Ignitor vs pilot
Faster fan startup (is this due to the draft inducer)
Hx design chages?
Anything else?



Yes.

The biggest improvement, IMO, is the ignition vs. the standing pilot.



Heatman,

But is it really cheaper to the consumer? I have a 25 year standing pilot
that I have replaced the thermo-couple once. I have a 10 year old 80% that
I have replaced the igniter on twice. I got off cheap because I know the
part only cost $16. But the average Joe in this part of the country pays
the HVAC man $75 for the part and a service call.

Plus you have to add in the cost of running the inducer fan and that igniter
uses a good bit of electricity every time it glows. KWH are cheap here but
what does it cost each time it glows where they cost more?

So who is coming out ahead here? Is the consumer really better off all
costs considered?

Serious questions.


Colbyt

HeatMan wrote:
"HL" wrote in message
news:tNurd.223772$df2.120623@edtnps89...

Compared to a 20 year old furnace how much does each design improvement
increase AFUE:

Draft inducer fan
Ignitor vs pilot
Faster fan startup (is this due to the draft inducer)
Hx design chages?
Anything else?




Yes.

The biggest improvement, IMO, is the ignition vs. the standing pilot.



You may be right about the biggest improvement, but the improvement
can't be much. My lowest gas bills in the summer are about $10 for
heating water with a water heater has a pilot light. I doubt that
the pilot accounts for more than 10 percent of the gas usage, so the
pilot probably cost about $1 per month or $12 per year.

BTW, I elected to install a water heater with a pilot light and am
glad that I did because operation is nearly silent. I would hate to
listen to an inducer fan every time the water heater burns; the damn
inducer fan on the furnace makes a lot of noise. More over, the pilot
light means that you continue to have plenty of hot water during
electrical outages. None of this applies to a furnace since you can't
operate it without electricity and the burner makes as much or more
noise than the inducer fan. But, it does go to suggest that the
benefits of electrical ignition is minor.

"HeatMan" wrote in message
.. .

"HL" wrote in message
news:tNurd.223772$df2.120623@edtnps89...
Compared to a 20 year old furnace how much does each design improvement
increase AFUE:

Draft inducer fan
Ignitor vs pilot
Faster fan startup (is this due to the draft inducer)
Hx design chages?
Anything else?



Yes.

The biggest improvement, IMO, is the ignition vs. the standing pilot.


So my 60% 20 year old furnace will achieve 80% by eliminating the pilot?

Why doesn't everyone just replace their pilots with an ignition system?

Doesn't quite add-up

The biggest improvement, IMO, is the ignition vs. the standing pilot.


So my 60% 20 year old furnace will achieve 80% by eliminating the pilot?

Why doesn't everyone just replace their pilots with an ignition system?

Doesn't quite add-up

I asked the HVAC tech who lives a few houses away about how much it
costs to replace my pilot light with an ignition system. He said that
his company charges $600 to do that. Presumably that's why it doesn't
get done often. He said that they sometimes have to add new boards to
make it work, etc. So I just shut mine off completely during the
summer and parts of the spring and fall. It's easy enoug to re-light
and I think it made a $5/month difference on my gas bill. I was using
less than $5/month for gas all summer long. Not exactly scientific,
but at these gas prices why not shut off the pilot whenever you can.

"Doug Warner" wrote in message
...
"HL" wrote:

Compared to a 20 year old furnace how much does each design improvement
increase AFUE:

Draft inducer fan
Ignitor vs pilot
Faster fan startup (is this due to the draft inducer)
Hx design chages?
Anything else?


Second heat exchanger, Extracts so much heat from the exhaust that
the water vapor in it condenses and runs out a drain (my condensate
pump runs summer AND winter) The inducer fan is needed because the
exhaust gases are too cool to rise up a chimney. Instead, they're
pushed out through a 3" PVC pipe that barely gets warm.

He's talking about the 80%, not the 92% stuff. The flue gases will rise up
the chimney, but will condense real bad and rot out the chimney quick

Other than that, you're correct....

"Colbyt" wrote in message
...

"HeatMan" wrote in message
.. .

"HL" wrote in message
news:tNurd.223772$df2.120623@edtnps89...
Compared to a 20 year old furnace how much does each design
improvement
increase AFUE:

Draft inducer fan
Ignitor vs pilot
Faster fan startup (is this due to the draft inducer)
Hx design chages?
Anything else?



Yes.

The biggest improvement, IMO, is the ignition vs. the standing pilot.



Heatman,

But is it really cheaper to the consumer? I have a 25 year standing pilot
that I have replaced the thermo-couple once. I have a 10 year old 80%
that
I have replaced the igniter on twice. I got off cheap because I know the
part only cost $16. But the average Joe in this part of the country pays
the HVAC man $75 for the part and a service call.


My Carrier POS has been in for 10 plus years and I haven't had to do
anything to it except for filters. What brand is it?

Plus you have to add in the cost of running the inducer fan and that
igniter
uses a good bit of electricity every time it glows. KWH are cheap here
but
what does it cost each time it glows where they cost more?


The efficiency rating is the annual rating. If you blew out your pilot
every year and didn't have to replace it, you'd gain a couple of efficiency
points.


So who is coming out ahead here? Is the consumer really better off all
costs considered?


See my first post.

BTW, that Carrier POS is a 2 pipe, one intake and one exhaust. That may
have something to do with the longevity of the ignitor.

"Rick" wrote in message
news:Xezrd.223872$df2.143177@edtnps89...

"HeatMan" wrote in message
.. .

"HL" wrote in message
news:tNurd.223772$df2.120623@edtnps89...
Compared to a 20 year old furnace how much does each design
improvement
increase AFUE:

Draft inducer fan
Ignitor vs pilot
Faster fan startup (is this due to the draft inducer)
Hx design chages?
Anything else?



Yes.

The biggest improvement, IMO, is the ignition vs. the standing pilot.


So my 60% 20 year old furnace will achieve 80% by eliminating the pilot?

Why doesn't everyone just replace their pilots with an ignition system?

Doesn't quite add-up



It's also the amount of gas being burned and used to warm up the house. The
ofrices are smaller and the HX is more efficient.

"Doug Warner" wrote in message
...
"HL" wrote:

Compared to a 20 year old furnace how much does each design improvement
increase AFUE:

Draft inducer fan
Ignitor vs pilot
Faster fan startup (is this due to the draft inducer)
Hx design chages?
Anything else?


Second heat exchanger, Extracts so much heat from the exhaust that
the water vapor in it condenses and runs out a drain (my condensate
pump runs summer AND winter) The inducer fan is needed because the
exhaust gases are too cool to rise up a chimney. Instead, they're
pushed out through a 3" PVC pipe that barely gets warm.
(Been using a Carrier SX since 1994)

Except what you are talking about isnt a 80% unit..its a 90% or better.


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