DIYbanter

DIYbanter (https://www.diybanter.com/)
-   Home Repair (https://www.diybanter.com/home-repair/)
-   -   Heat loss from furnace via flue ? (https://www.diybanter.com/home-repair/143554-heat-loss-furnace-via-flue.html)

[email protected] February 6th 06 04:30 AM

Heat loss from furnace via flue ?
 
Hello, I have a typical gas furnace, 80% efficient, so it uses a
chimney. A 4" metal flue pipe comes out of the front/top of the
furnace, wraps around towards the back towards the wall behind which is
the chimney. Total of about 6 feet of 4" flue pipe, looks properly
installed. The 4" pipe goes into an 8" pipe which goes into the wall,
and the chimney is inside the wall right there.

My gas bills are horrendous I should add.

Tonight for some reason I felt the flue pipe while the furnace was
running and the thing is hot as blazes. Even at the end of the 6' run
of 4" pipe, you can't even keep your finger on the flue pipe for more
than a couple seconds cause it's so hot.

Is there some way to capture this heat ? If so, what do I look into ?
I must be heating half the country.

Thank you !


RP February 6th 06 05:03 AM

Heat loss from furnace via flue ?
 


wrote:
Hello, I have a typical gas furnace, 80% efficient, so it uses a
chimney. A 4" metal flue pipe comes out of the front/top of the
furnace, wraps around towards the back towards the wall behind which is
the chimney. Total of about 6 feet of 4" flue pipe, looks properly
installed. The 4" pipe goes into an 8" pipe which goes into the wall,
and the chimney is inside the wall right there.

My gas bills are horrendous I should add.

Tonight for some reason I felt the flue pipe while the furnace was
running and the thing is hot as blazes. Even at the end of the 6' run
of 4" pipe, you can't even keep your finger on the flue pipe for more
than a couple seconds cause it's so hot.

Is there some way to capture this heat ? If so, what do I look into ?
I must be heating half the country.

Thank you !


Rip it out and install a 96% furnace. The problem with using something
like a heat recovery ventilator to capture your lost heat is that
further cooling of the flue product will result in vapor condensation
and will simultaneously interfere with proper draft. By the time you
call in an engineer to resolve these issues and make the modifications
safely, you could've replaced it with a more efficient unit. Not only
that, but any modification will raise liability issues that wouldn't be
in your favor.

Richard Perry


Mark & Mary Ann Weiss February 6th 06 09:23 AM

Heat loss from furnace via flue ?
 



Tonight for some reason I felt the flue pipe while the furnace was
running and the thing is hot as blazes. Even at the end of the 6' run
of 4" pipe, you can't even keep your finger on the flue pipe for more
than a couple seconds cause it's so hot.

Is there some way to capture this heat ? If so, what do I look into ?
I must be heating half the country.

Thank you !



You can try a flue damper, to prevent cold air from backing down into your
gas furnace.

Grainger may have just what you're looking for:

http://www.grainger.com/Grainger/wwg...i=xi&ItemId=16
11758442&ccitem=



--
Take care,

Mark & Mary Ann Weiss

VIDEO PRODUCTION . FILM SCANNING . DVD MASTERING . AUDIO RESTORATION
Hear my Kurzweil Creations at: http://www.dv-clips.com/theater.htm
Business sites at:
www.dv-clips.com
www.mwcomms.com
www.adventuresinanimemusic.com --Now with Hi-Fi Stereo Streaming Audio!
-



buffalobill February 6th 06 10:45 AM

Heat loss from furnace via flue ?
 
general info for your furnaces:
http://www.misterfix-it.com/Solutions/5Air.html


whodat February 6th 06 02:27 PM

Heat loss from furnace via flue ?
 

"My gas bills are horrendous I should add"

join the club

keyspan/lipa what ever the hell its called now, raised gas 40%, .thats
with a mild winter.

is this warm air heat you have?

you normally cannot hold on to a flue pipe from any heating appliance,
unless its one of thos 94% high efficiency warm air jobs.

theres nothing to retrofit a gas flue pipe with..
unless its a boiler that will accept an electric stack damper,
that doesnt save on running time, only off time as it prevents the
chimney from pulling on the hot boiler.


--
whodat
------------------------------------------------------------------------
whodat's Profile: http://www.HomeOutfit.com/member.php?userid=35
View this thread: http://www.HomeOutfit.com/showthread.php?t=66554


[email protected] February 6th 06 02:54 PM

Heat loss from furnace via flue ?
 
They USED to sell something like what she or he wanted, but cooling the
flu gas caused mega troubles and some deaths.

about the best you can do is a automatic flue damper, it closes when
the furnace isnt running,

just think every furnace exhauts a heated air out the chimney 24/7

just think of that when you pay your gas bill


[email protected] February 6th 06 03:01 PM

Heat loss from furnace via flue ?
 
Some of those electrical heat sinks on the flue might warm up your
basement a little bit. Other than that, a more efficient furnace might
be the best bet. More insulation would help too.


[email protected] February 6th 06 03:25 PM

Heat loss from furnace via flue ?
 
I was afraid I might be stuck between a rock and a hard place. We have
one really good HVAC company in town, I'll see what they think. Also
may take some infrared pictures to see if there's more leaks I don't
know about. My furnace is only 8 years old and is 80%, so canning the
whole thing and going 96% is a money hit I was not prepared for.

I wonder if having half my vents shut (to redirect most of the heat to
one end of the house) could affect things.

If this warm winter was typical I'd be tempted toward heat pump, our
electrical rates are low here but at 40 deg N latitude, heat pump is a
tough one.


m Ransley February 6th 06 04:34 PM

Heat loss from furnace via flue ?
 
An aftermarket damper must have a lockout to the furnace incase it
doesnt open, There have been alot of cases where they failed leading to
Co issues. I think the cost will be excessive compared to a new unit
with a starting high efficiency, meaning payback is poor. You could be
reducing furnace efficiency and harm the furnace if closing vents
increases temp rise to much. A friend bough a house where the ac coil
was clogged shut, he removed it to clean it and his bills dropped in
half. You really need your system serviced to find out if it is running
optimaly and go through your options for an upgrade.


[email protected] February 6th 06 05:12 PM

Heat loss from furnace via flue ?
 
I had it serviced, it runs fine, that is, it's working exactly as
designed.

I would dearly love to bag our gas company and go heat pump and
electric hot water - is that a ludicrous idea in Columbus Ohio ? Maybe
I'm too emotional about my $400 gas bills.

Thank you !


mm February 6th 06 05:52 PM

Heat loss from furnace via flue ?
 
On Mon, 6 Feb 2006 09:34:35 -0600, (m Ransley)
wrote:

An aftermarket damper must have a lockout to the furnace incase it
doesnt open, There have been alot of cases where they failed leading to
Co issues. I think the cost will be excessive compared to a new unit
with a starting high efficiency, meaning payback is poor. You could be
reducing furnace efficiency and harm the furnace if closing vents
increases temp rise to much. A friend bough a house where the ac coil
was clogged shut, he removed it to clean it and his bills dropped in
half.


I hHadn't thought about that before you just mentinoed it.

What does one do when his AC coil is stuck inside the duct and not
accessible? Is that common? Did the guy you mention have to cut a
big hole in the duct to clean his coil?

I had to cut a little hole in my duct just to see why the condensate
was dribbling all over the floor, instead of going down the pipe.

My coil has never been cleaned, and I suppose there is a good chance
it is dirty, clogging the system and wasting fuel.

You really need your system serviced to find out if it is running
optimaly and go through your options for an upgrade.



Remove NOPSAM to email me. Please let
me know if you have posted also.

[email protected] February 6th 06 06:14 PM

Heat loss from furnace via flue ?
 
Depending, exhaust temp might not be _that_ high. For one thing,
depends on sensitivity of your digits.

For many, 150F is considered limit for "sustained" contact. For a flue
pipe, that's pretty cold. To recover much more heat from the exhaust,
you'd better be prepared to deal with condensate, corrosion probs, etc.

Were I you, I'd suggest obsessing on all the many ways your house and
its occupants waste energy. Get a good clock thermostat, and see just
how much setback you can handle. Electric blankets work great, a/r, I'm
told.

J


Brian February 7th 06 12:46 AM

Heat loss from furnace via flue ?
 
There used to be 82% and even 84% efficient furnaces, but
manufactures learned very quickly that cooling flu gasses
cases big problems....

Don't listen to who ever suggested replace it with 90%.....

Waste of money. So if you currently pay $350/month you would
save 35$ - 40$. That is stupid. Go with dual fuel HeatPump.

I am getting rapped by Vectren too. Switching off is the only answer.


[email protected] February 7th 06 03:03 PM

Heat loss from furnace via flue ?
 
Get a geothermal heat pump. More efficient than a regular heat pump,
and no need for electric backup.


udarrell February 7th 06 03:40 PM

Heat loss from furnace via flue ?
 
mm wrote:

On Mon, 6 Feb 2006 09:34:35 -0600, (m Ransley)
wrote:



An aftermarket damper must have a lockout to the furnace incase it
doesnt open, There have been alot of cases where they failed leading to
Co issues. I think the cost will be excessive compared to a new unit
with a starting high efficiency, meaning payback is poor. You could be
reducing furnace efficiency and harm the furnace if closing vents
increases temp rise to much. A friend bough a house where the ac coil
was clogged shut, he removed it to clean it and his bills dropped in
half.



I hadn't thought about that before you mentinoed it.

What does one do when his AC coil is stuck inside the duct and not
accessible? Is that common? Did the guy you mention have to cut a
big hole in the duct to clean his coil?

I had to cut a little hole in my duct just to see why the condensate
was dribbling all over the floor, instead of going down the pipe.

My coil has never been cleaned, and I suppose there is a good chance
it is dirty, clogging the system and wasting fuel.


The system installer(s) should retrofit evaporator coil access door
plates when coils are in ducts.
Encased coils should be manufactured with easily removed access panels;
we should demand this be done!
Clean coils are an absolute must condition!

You really need your system serviced to find out if it is running
optimaly and go through your options for an upgrade.


The manufacturers' ought to consider the required future service and
maintenance necessary to efficient and long life operation of their
brand of equipment.
All A/C equipment should also be manufactured for easy static pressure
testing before and after the evaporator coil and the return air filter.
http://www.udarrell.com/external_sta..._readings.html
Those servicing advantages could be their strongest marketing selling
points!
- udarrell - Darrell

--
The Money Saving Free Satellite TV System Gift Offer of a Life-Time. Don't miss this opportunity for you and all your friends, - they will be forever Grateful. My life's mission: saving you and your friends a lot of money in every possible way.

http://www.udarrell.com/free_dish_di...ellite_tv.html

m Ransley February 7th 06 04:07 PM

Heat loss from furnace via flue ?
 
BrownTiger , your miss under standings and inaccurate statements are all
to common among the masses, an 94.5% unit is 18% more efficient than an
80% unit. That is 18% savings at todays Ng prices. You really can`t be
that ignorant to think Ng won`t double again in 10-15 years, it always
has and always will. Therefore his Payback will be great even
considering lost interest . What do your investments and interest on
money return you.


[email protected] February 7th 06 04:56 PM

Heat loss from furnace via flue ?
 
Brian wrote:
There used to be 82% and even 84% efficient furnaces, but
manufactures learned very quickly that cooling flu gasses
cases big problems....


Oh, so I guess they stopped making anything more efficient than 80%?



Don't listen to who ever suggested replace it with 90%.....

Waste of money. So if you currently pay $350/month you would
save 35$ - 40$. That is stupid.


Since when is saving $40 a month stupid? Now if you mean he may not
come out ahead by replacing his current furnace, that depends on how
much it will cost and how long he will be living there.


Go with dual fuel HeatPump.


Well, I guess you don't mean the economics I mentioned above, since now
you say it's OK to just replace what he has with a heat pump. And the
fact that he already has high gas bills should be a clue that a heat
pump would likely be even more costly to run in that kind of
environment.


[email protected] February 7th 06 07:03 PM

Heat loss from furnace via flue ?
 
ahh 90% or whatever efficeny rate is under 100% operation, time wise!

In most cases a furnace doesnt run continiously, so 90% isnt reached.

high efficency furnaces start the blower when the gas turns on, blowing
what feels like cold air, when the customer complains the on temp is
increased for cmfort, but it lowers efficency.

all of these have to be considered in the mix


RP February 7th 06 07:25 PM

Heat loss from furnace via flue ?
 


wrote:

ahh 90% or whatever efficeny rate is under 100% operation, time wise!

In most cases a furnace doesnt run continiously, so 90% isnt reached.

high efficency furnaces start the blower when the gas turns on, blowing
what feels like cold air, when the customer complains the on temp is
increased for cmfort, but it lowers efficency.

all of these have to be considered in the mix


DOA. Google AFUE to find out why you're talking nonsense.

Richard Perry




RP February 7th 06 07:28 PM

Heat loss from furnace via flue ?
 


wrote:

ahh 90% or whatever efficeny rate is under 100% operation, time wise!

In most cases a furnace doesnt run continiously, so 90% isnt reached.

high efficency furnaces start the blower when the gas turns on, blowing
what feels like cold air, when the customer complains the on temp is
increased for cmfort, but it lowers efficency.

all of these have to be considered in the mix


Here, I googled it for you.

http://www.furnacecompare.com/faq/definitions/afue.html

"[...] The DOE's technical definition of AFUE is as follows:

The measure of seasonal or annual efficiency of a furnace or
boiler. It takes into account the cyclic on/off operation and associated
energy losses of the heating unit as it responds to changes in the load,
which in turn is affected by changes in weather and occupant controls. "

Richard Perry


[email protected] February 7th 06 10:34 PM

Heat loss from furnace via flue ?
 
I will have to ask my friend who taught HVAC. He said more efficent is
better, and likes 90+% variable speed furnaces, but did note going from
my present 69 to 93 will NOT cut the gas bill by the percentage it
appears. Have several friends who replaced their furnaces and noted
exactly the same thing.

Bill went down but not as much as anticipated:(

heat pumps cost way more to operate than forced air gas


RP February 8th 06 01:37 AM

Heat loss from furnace via flue ?
 


wrote:
I will have to ask my friend who taught HVAC. He said more efficent is
better, and likes 90+% variable speed furnaces, but did note going from
my present 69 to 93 will NOT cut the gas bill by the percentage it
appears. Have several friends who replaced their furnaces and noted
exactly the same thing.


Your gas bill isn't proportional to your gas usage. There are other
charges besides the gas charge. Additionally, if you have other gas
appliances, then you have to prorate your fuel usage accordingly. You
can't just take the total bill and multiply by 24% to get the estimated
energy savings for the new unit. Sorry, but it isn't that simple. :)


Bill went down but not as much as anticipated:(

heat pumps cost way more to operate than forced air gas.


Not around here they don't.

Richard Perry


julie japczyk October 18th 19 06:14 PM

Heat loss from furnace via flue ?
 
replying to roger61611, julie japczyk wrote:
My flue goes out the side of basement wall

--
for full context, visit https://www.homeownershub.com/mainte...lue-87544-.htm




All times are GMT +1. The time now is 01:21 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 DIYbanter