standing pilot gas usage

veesubotee

This spring, I replaced my 20 year old Rheem furnace with a new 94+ efficient model.

Trying to compile gas savings from my old bills and wonder if any of the PROs could approximate (cu ft) how much a standing pilot would consume.

Thanks.

V

hvaclover

To keep it simple during saving calculations the industry accepted rate was 10%.

Hope that helps.

BTW how is the new system working?

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veesubotee

Would that be 10% of the input BTUs? The old beast was a 125,000 behemoth. Wow, 12,500. I can't imagine 10 times that little trickle equaling those 4 burners, but that large number will make my savings look better. Oh, well.

Got a Rheem Modulating furnace 90,000. A 75 probably would have covered me, but needed the 4 ton blower for a/c. Love that LOoooonnng gentle heat.

Thanks.

V
P.S., you needs to file down them teeth.

veesubotee

Would that be 10% of the input BTUs? The old beast was a 125,000 behemoth. Wow, 12,500. I can't imagine 10 times that little trickle equaling those 4 burners, but that large number will make my savings look better. Oh, well.

Got a Rheem Modulating furnace 90,000. A 75 probably would have covered me, but needed the 4 ton blower for a/c. Love that LOoooonnng gentle heat.

Thanks.

V
P.S., you needs to file down them teeth.

hvaclover

Those teeth are "Lady Killers". LOL

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veesubotee

O.K., I'll let the teeth slide, but when you say 10%, are you saying that doing away with the pilot saves 10%?

V

hvaclover

that was the hype when they went from standing pilot to spark.

All the furnaces that came off the assembly line were classified as 70% efficient,

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veesubotee

Well, not being a nit picker (read, pain in the ass), I went exploring on the net. Came up with a very interesting link: http://www.osti.gov/energycitations/...sti_id=6471521 .

One paragraph read in part: "Overall, elimination of the pilots would have conserved only 2.6% of the total gas energy used in this home (3.1% if the home was air-conditioned)".

So what I intend to do is subtract about 2% to my calculated other use gas consumption for the non-heating months .

hvaclover

I see no need to justify my response to you. At the time the generation furnaces after standing pilot were all GAMA to 70% according to US DOE standards. If you found something you like better than don't ask if you get a answer you don't like.


You would be wise to compare the Gama data to what you are now looking at. There are some allowances and dis in design to consider.

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beenthere

Different units/brands, had different pilot set ups.
Some used more gas then others.
Also.
That study did not test for the effect of the increase in infiltration that a standing pilot has on a house.
The uncrease of infiltration increases a homes heat loss. But that was not considered, or allowed for in that study.

That study is flawed in reguards to saving on heating and cooling cost.

veesubotee

Hey Lover, don't be mad. I'm was just trying to understand what you are saying. I misunderstood your original statement (70%) as referring to furnaces of 80% AFUE (80 - 10 = 70). Probably still do.

I looked at GAMA and it's way over my head.

My old beast was built in 1987. Don't know if 80s were around then.

What I was trying to do, was compare my old gas usage on a therms per heating degree day basis. I know that HDDs are based on average temperatures without any weighting, but over the period of a year, the errors should be a wash.

To try to get as accurate figures as possible, I used my gas consumption during the non-heating months as my baseline (cooking and hot water) use. I didn't make any allowance for the pilot which has been on year 'round. That was the basis for my original question.

So, thanks and sorry to have ruffled your feathers. I'll let you bite me in the neck.

V

hvaclover

Hey Been, how's the family?
Are you Talking about the efficiency standards Gama used to first assign the 70% rating and the later arguments that later disallowed jacket heat losses or the study the OP mentioned?

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beenthere

The study the OP posted.

Families doing good. Thanks.

How bout yours.

hvaclover

My wife is sweating bullets over the so called "Big Three Bail Out".

She works at Chrysler and is worried sick if she is going to have a job tomorrow.

otherwise everything is peachy.lol

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Martinglmt

I have info on gas fireplaces, which should be relatively close to an older furnace...the gas valves in most current gas fireplaces use around 30,000 BTU's a day = about 110 therms a year. A NG therm costs constantly change but can routinely cost anywhere from 1.00 to 1.50. End result is about $100 to $150 a year. We(fireplace supplier) usually quote $10 to $12 to operate a NG pilot.

New fireplaces have an option for electronic ignition, which eliminates the need for an standing pilot...and then a $10 a month savings. Homeowners have to determine if they want to invest in the extra cost to have the electronic ignition option vs. the cost of operating a standing pilot.