Rod Fox
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  • Cerrillos, NM
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Does altitude affect AFUE? or just the input/output BTUs?
21 Replies

I searched and searched and searched yesterday for an answer to the question "Does altitude affect AFUE?" but did not come up with any definitive answers. Hopefully this discussion will answer that…Continue

Tags: derate, input, BTUH, altitude, SSE

Started this discussion. Last reply by Dale Pickard yesterday.

Utility company's diabolical rate plans don't save the consumer equivalent to what they conserve
6 Replies

Attached is a spreadsheet I created for a restaurant client comparing two plans and projected kWh savings at 20% and 30%.Currently, they are on the rate plan "3B". If they were to remain on this plan…Continue

Tags: savings, vs, actual, plans, rate

Started this discussion. Last reply by Bud Poll Aug 13, 2012.

Efficiency First Membership Pricing
4 Replies

Does anyone else find the $300 membership fee a bit rich for a business consisting of only one self-employed owner?At $100 I might consider it, but at $300 they've pretty much prevented me from…Continue

Tags: overpriced, membership, first, efficiency

Started this discussion. Last reply by Rod Fox Jul 26, 2012.

Utility Meter Accuracy
40 Replies

Well I have to admit that I'm stumped with an energy audit I've been working on for the past two months. Perhaps someone can point me in the right direction...My client contacted me concerned that…Continue

Tags: accuracy, meter, utility

Started this discussion. Last reply by Rod Fox Jul 26, 2012.

 

Rod Fox's Page

Latest Activity

Dale Pickard replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"Morgan, I got this below from the Knight installation manual. I note a few things, -These recommendations are not the "4% for every 1000 ft above 2000 ft" appropriate for natural draft boilers. -They do indicate will derate itself 4% for…"
yesterday
Dale Pickard replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"Hans, The car manufacturer's are doing it with mass flow sensors and oxygen sensors "lamda" sensors to operate the fuel injection and gas air mix, even dynamically as the car gains altitude. Gas fuels are different from liquid or even…"
yesterday
Dale Pickard replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"I was trying to avoid naming manufacturers, but I was going by the published information for the smaller Knight boilers which use the "fire tube hx". Check me but I understood there was a derating schedule for these boilers. Also note, the…"
yesterday
Eric Kjelshus replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"I look at this not about AFUE,  but flue gas dewpoint.  If your burn rate is rotting the heat exchanger then you have short life of heating system.   Old school is about dewpoint -  if natural gas flue products are at 130'F…"
yesterday
Morgan M Audetat replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"Though Viessmann is relatively unique in the application of Lambda technology to condensing boilers, most condensing boilers (I have installed 12 manufacturers) burning natural gas will not have to adjusted for altitude up to 6,000 feet or so.…"
yesterday
Eric Kjelshus replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"The heat exchanger gets burnt out, if presser is to high or if mix is to rich, then I see holes in the heat exchanger.   I have done gas wells with low and high BTU content and have to test each one with 55 gal of Nat gas with some presser.…"
Friday
Hans Joachim Preiss replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"Good discussion. I came across this comprehensive presentation by Gas Consultants on the effects at high altitude. Although it doesn't say why utilities dilute gas (see slide…"
Friday
Dale Pickard replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"Excellent reply Hans. I think that there isnt' a good general answer to this question but that with anything but atmospheric equipment the manufacturers suggestions should be followed. The condensing boiler I've been working with for over…"
Friday
Rod Fox replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"Hans,Putting it the way you spelled it out so well helped me understand the whole process. So thanks also for your comments. I think this question has now been adequately answered! Thanks to everyone in this community. This website is full of…"
Jun 26
Rod Fox replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"Dale, I appreciate your comments, they make perfect sense. It seemed to me when I was researching this in the past that I came to the same conclusion as you, that it's actually possible the efficiency improves with altitude. Not sure I actually…"
Jun 26
Hans Joachim Preiss replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"Rod, Correct me if I am wrong, but you're saying "AFUE" but really mean "actual efficiency". AFUE is measured under controlled conditions in a lab at or near sea level, and has little in common with the actual efficiency…"
Jun 26
Eric Kjelshus replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"Afue is not a real number.   Look at system Efficiency BTU in vs BTU out,  Its more real.    Look at gas sold in boston most of east big citys are at 1050 BTU's per cub foot   Kansas City is about 950-1050  …"
Jun 25
Morgan M Audetat replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"I beg your pardon Rod, To answer your question, Dale has it right of course.  There are two ways to adjust for altitude above 2000 ft. elevation. One is to de-rate the appliance and the other is to de-rate the gas.  Here in Minneapolis we…"
Jun 19
Dale Pickard replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"Hello Rod, I don't think that de-rating atmospheric boilers for altitude should affect efficiency, either "annual" or instantaneous - just output. If anything the output might increase some as the heat exchanger in the de-rated boiler…"
Jun 19
Rod Fox replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"Well, I don't really think I asked the wrong question, "Does altitude affect AFUE?" Because that's what I wanted to know. That's the number I use in many calculations, to present to the layman (my customers)…"
Jun 17, 2014
Morgan M Audetat replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"First, it is the wrong question. AFUE is a comparative consumer number whereby the layman is presumably assisted in choosing an appliance by its advertised efficiency.  If we are addressing condensing appliances, all others being a waste of…"
Jun 17, 2014

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Advanced Metrics Group
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BPI Building Analyst Professional
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Renewable energy systems
Simplification
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At 1:03pm on January 4, 2011, Diane Chojnowski said…

Hi Rod,

Welcome to Home Energy Pros! Feel free to join the conversation in the Forum and Groups. And share your energy efficiency photos, videos and upcoming events. If you're blogging about home performance, this is the
place for you!

Don't forget to upload your profile photo. And, add your location on our Member Map!

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Diane, HEP Moderator

 
 
 

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Dale Pickard replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"Morgan, I got this below from the Knight installation manual. I note a few things, -These…"
yesterday
Dale Pickard replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"Hans, The car manufacturer's are doing it with mass flow sensors and oxygen sensors…"
yesterday
Dale Pickard replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"I was trying to avoid naming manufacturers, but I was going by the published information for the…"
yesterday
Eric Kjelshus replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"I look at this not about AFUE,  but flue gas dewpoint.  If your burn rate is rotting the…"
yesterday
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"Nickie -  Good points. I think it is easy enough to flag or designate projects that achieve…"
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Morgan M Audetat replied to Rod Fox's discussion Does altitude affect AFUE? or just the input/output BTUs?
"Though Viessmann is relatively unique in the application of Lambda technology to condensing…"
yesterday

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