Furnace/Boiler Efficiency Debate

Tim_33

Is what this is. 13 SEER mandated everywhere for AC, but 80% burners are OK?

What kind of nonsense is the blurb about "more forgiving"? Frankly, it is a lot easier for the average hack to vent an appliance in PVC, than to ge a natural draft appliance vented properly. Any plumber can do that. The argument is missing the practicality of logic. Regional requirements are reasonable.

All the work involved in pushing the paper required to change from 78 to 80% was a complete waste. Outside of the cheapest large appliances, you can't fing 78% efficent equipment anymore.

I analyzed the payback years ago when installing a central AC in my well shaded and well insulated/seal house in northern IL, between a 10 SEER unit and a 12 SEER unit. The payback was 18 years, and that was conservative. 13 is an utter waste. The difference in heating between 80% and 92% was about 3 years. Both standards should be based on climatic data: HDD and CDD.

Steve_126

New Rules Barely Budge Furnace-Efficiency Level: Cindy Skrzycki
2006-10-24 00:05 (New York)


By Cindy Skrzycki
Oct. 24 (Bloomberg) -- The U.S. Department of Energy has decided to keep the home fires burning at about the same level as they are now, even in the face of lobbying by both energy-conservation groups and some manufacturers.
A proposed ``energy conservation standard'' the department unveiled Oct. 6 moved the energy-efficiency needle imperceptibly for home gas furnaces -- to 80 percent from 78 percent, the standard set in 1989. The agency rejected an option to raise the standard to 90 percent, which would have saved more energy and trimmed heating bills for consumers in colder climates.
The long-awaited announcement frustrated energy groups who lobbied for a significant increase in efficiency as well as parts of the industry that wanted to see more robust standards for some heating units.
Department officials said a higher standard wouldn't have been cost-effective for those in states with mild winters to only
have the option of buying a furnace that is 90 percent efficient, which means it turns 90 percent of the fuel into heat.
The department also turned down some innovative ideas from energy groups and manufacturers, saying it didn't have the authority to act. The agency rejected the idea of a regional standard, which would make the highest efficiency rating applicable only to the coldest states. Instead, it said states could apply for exemptions to the rule if they wanted a tougher standard.

Hardly a Change

The regulators also gave thumbs down to a plan advanced by
the boiler industry and energy groups to increase efficiency in gas models. They proposed eliminating pilot lights and installing a reset mechanism that automatically adjusts to the outside air temperature.
Setting the standard at 80 percent represents virtually no change, since almost all new regular gas furnaces now are at least that efficient. Furnace makers such as Trane, a division of American Standard Cos., Carrier Corp., a division of United Technologies
Corp., and Lennox Industries also sell products that are more than 90 percent efficient. Sales of those models have been brisk in northeastern states. And three states -- Vermont, Massachusetts and Rhode Island -- have passed laws setting the requirement for gas furnaces at 90 percent, a standard that has to be approved by federal regulators.
Massachusetts residents would pay about $540 more for a
furnace rated 90 than for a basic unit, yet could save $125 a year on energy use, according to estimates by the Appliance Standards Awareness Project, a business and consumer-advocacy group in Boston.

`Narrow View'

The Department of Energy ``seems to be looking for the
narrowest possible way to comply with the law, and cost-effective energy savings were clearly of secondary importance,'' said Steven Nadel, executive director of the American Council for an Energy Efficient Economy, a non-profit research group based in Washington.
There is intense interest in the proposal because 3.5
million gas furnaces and 300,000 residential boilers were sold last year. Department officials said that in rejecting a higher standard, they took into account manufacturers' concerns that there were potential condensation and venting problems when efficiency ratings are set between 80 percent and 90 percent.

Flexibility

``The department's proposal sets a national standard, but still gives states as much flexibility as we can under the statute,'' said David Rodgers, acting deputy assistant secretary for technology development in the department's Office of Energy Efficiency and Renewable Energy. Rodgers said the law requires the agency to consider
standards that are economically justifiable, technologically
feasible, and save a significant amount of energy.
Under the Energy Policy and Conservation Act, the Energy Department is charged with reviewing the efficiency of commercial and residential appliances and equipment, including refrigerators, washers and dryers, air conditioning and furnaces. The agency has fallen years behind in issuing the efficiency standards and now is under pressure from Congress to get on a schedule and stick with it. In September 2005, the Natural Resources Defense Council, a national environmental group, joined with 15 states and two consumer organizations in going to court
in New York. They asked that the department face a legally
binding deadline for issuing 22 energy-efficiency standards -- including this one.
In a report to Congress last January, the agency said it is committed to addressing the backlog and has set ``firm and achievable'' schedules.

No Priority

In the case of furnaces and boilers, work on a new standard began in 1993 but didn't receive priority status at the Energy Department until 2001. The first published notice of a rulemaking came in July 2004, and the department expects to complete the rule sometime next year. Much to the chagrin of energy advocates, it said the effective date won't be until Jan. 1, 2015.
``It's absurd to set such a weak standard and not implement until 2015,'' said Andrew deLaski, executive director of the Appliance Standards Awareness Project.
Joseph Mattingly, general counsel for the Gas Appliance
Manufacturers Association in Arlington, Virginia, said the
industry urged setting the standard at 80 percent because that level avoids safety concerns.

Regional Standard

``In a perfect world, the units would be installed according to manufacturers' instructions, so we have to have something that is forgiving of less-than-perfect installation,'' said Mattingly. He said consumers outside of cold-weather states were not likely to need a high-efficiency furnace. Energy advocates tried to address cost and safety issues by supporting a regional standard: one at 90 percent for states above Maryland and one at 80 percent below it.
The industry opposed that and likes the idea of states
setting their own standards even less. It told the Energy
Department that encouraging states to override the federal
standard is ``an abuse of discretion.''A big disappointment for both sides was the department's rejection of an agreement between 28 manufacturers of oil and gas
boilers and four energy-efficiency organizations.
``DOE at every juncture finds a reason to follow a less
energy-efficient path,'' said deLaski. ``Even when business says, `Give us more efficiency,' they say no.'' Mattingly said the industry will ask the department to make
a ``limited policy exemption'' to accept the agreement. Energygroups said adopting it would save twice as much energy for gas boilers than the standard that the department proposed.

(Cindy Skrzycki is a regulatory columnist for Bloomberg
News.)

jp_2

steel, auto,electroncs

well just looks like more jobs lost to imports who will increase efficiences.

like the auto industry who thought the cars were good enough, then the japanese whips our butts, the TV market that went to the japanese who built better ones, etc......

why wouldn't a company strive to be the best? which industry has thrived without this ideal?

Paul Pollets

When the Government gets Serious...

When the federal government gets serious about saving energy, than the efficiency regs will be upgraded. This administration has been a joke when it comes to putting a real energy policy in place. It's disgraceful and the world is watching.

In the meantime, homeowner's will continue to be confused by "AFUE" and glossy brochures overstating the efficiency of the appliances.

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Mike T., Swampeast MO

That final topic "Regional Standard" is the most disheartening to me.

zeke

Nowhere in this message do I see the equation of the impact of increasing mandated efficiencies with the actual willingness of the HO to go out and scrap his "inefficient" unit for a new one. For example, if the government increases the mandated efficiency to 93% at an increased cost of say $1500 for a heating system, then it may be that almost nobody will be willing to change out a 70% efficient unit, from a purely economic considerartion. So then by this scenario, the government will have done NOTHING to alleviate the energy crisis. Also, I am wary of manufacturers getting into this, since most are interest in their bottom line and not necessarily the welfare of the country or the world. I also wonder if a free market approach might be better with a better incentive program to the HO to encourage the purchase of high efficiency systems.
I also think we need somebody like Brownie to run the program to make a total mess out of it.

Mike T., Swampeast MO

The devil's advocate part of me does understand why it's impractical for the federal government to produce a country-wide standard for efficiency of space heating appliances in this VAST country with WILDLY diverse climates.

The "states rights" part of me says that such truly should be implemented by the individual states--with GUIDANCE from the resources of the federal government. SURELY part of the reason that individual taxpayers fund the US Department of Energy is for them to determine how to use energy in an efficient manner.

The "individual rights" part of me says that we should all be free to be as efficient or as wasteful as we want. After all I'm from "wood country" where LOTS of wood is burned for space heating at efficiency rates that are truly dismal--coal would be significantly better... Such TRULY hurts the "environmental" part of me as I find such to be a HIDEOUS squandering of energy and I NEVER want to loose my trees!!!!!!!!!!!!!!!

The "understand the industry" part of me says that MUCH of this problem is truly about the difference between hydronic and air systems. I have the actual DOE regulations regarding AFUE in my "reading room" and am trying to work my way through. Rather difficult as the true guts of AFUE are based on information from ASHRAE--not only for the actual testing but for how heat loss is determined. What truly troubles me however is that the DOE claims that AFUE is a REAL WORLD measure of efficiency! If you don't believe me, Google the definition of AFUE from the DOE. The language is NOT ambiguous.

The "conspiracy theorist" part of me says that forced air manufacturers and ASHRAE really don't want anyone to know the TRUE efficiency of furnaces in real-world installations while they ALL know that hydronics are significantly more efficient yet for some crazy reason they're measured on the same scale.

The "hydronic advocist" part of me (and NEVER call me an "activist" as I will NEVER be blindsided--an "activist is and activist is an activist" just as a "rose is a rose is a rose") finds US manufacturers of boilers utterly screwed by all of the above. They have no incentive to develop the finest and most efficient systems because they're being measured against furnaces!!!!!

Frenchie

Zeke

HA HA that is funny! I think brownie could probably use the work!

Mike T., Swampeast MO

Advocist

Did I make a new word?

More than an advocate but less than an activist?

jcarta

DEPT OF ENERGY

SHAME ON YOU THE DEPT OF ENERGY-GERMANY AND MANY OTHER COUNTRIES FORCE EFFICIENCY/UPGRADES AND REGULAR SERVICE TO MAINTAIN ENERGY SAVINGS-WE CANT EVEN SET A MINIMUM EFFECTIVE STANDARD FOR THE LOOMING ENERGY CRISIS-SURE IT COSTS ALITTLE MORE UPFRONT BUT ITS THE SAVING OVER THE LONG RUN-WE REALLY DONT KNOW HOW OR WANT TO SAVE ENERGY BECAUSE WE CANT SHOW IT OFF LIKE THE GRANITE COUNTER TOP IN OUR KITCHEN

Steve_35

No, it's because the populace of countries like Germany

are akin to lemmings in that they will do as told by higher authority. Fortunately, IMO, things are different in the US. Not only do we have the freedom to make choices, good and bad, but we actually resent having choices taken from us or enforced onto us from on high.

On a side note, I REALLY like the new Firefox. It finds my typos while filling out forms like this. Too cool.

Brad White_137

\"Forcing Efficiency\"

"SHAME ON YOU THE DEPT OF ENERGY-GERMANY AND MANY OTHER COUNTRIES FORCE EFFICIENCY/UPGRADES AND REGULAR SERVICE TO MAINTAIN ENERGY SAVINGS-WE CANT EVEN SET A MINIMUM EFFECTIVE STANDARD FOR THE LOOMING ENERGY CRISIS"....
I agree with Pitman-
With all due respect, do you really want a government to dictate to you rather than having the consumer, paying the freight, follow the laws of economics in a free market? I have faith in the free market and folks always follow their best economic interest. They will demand better efficiency and the market will respond. Companies which do not meet the demand, go under.

All for setting guidelines, fine. But to limit the offerings, I hope not....

Constantin

In defense of the DoE...

... in some respects their hands are tied.

For example, any new energy efficiency standard is predicated on a an economic payback in a few years. The cost of the fuel is determined by the EIA, which until recently projected gas prices at 1/2 of reality and electricity prices at 8 cents/kWh to 2030. With a requirement to use absurdly low energy prices, it becomes much harder to justify higher efficiencies on a payback basis.

Next, any minimum energy standard that might affect the competitiveness of the market players is also nixed. Thus, any manufacturer that missed the high-efficiency bandwagon may claim that the new rules could run them out of business, their congressman/woman complains, etc. I think it was Dan at some point that described the glee with which the boiler company advocates described quashing higher standards?

I will not bore you with all the complex steps it takes to get a rulemaking out (I'm in the midst of a couple) but I bet you would be surprised to see just how much analysis goes into each standard, as required by the act of congress in 1979 that amended the original 1973 charter to set minimum standards.

That the executive has an impact on the urgencies of standard-setting is no question either, Bill Clinton set a couple in his last days in office and George Bush promptly tried to turn some of them back. Whether the DoE energy program suffered from neglect for the last 6 years is for other people to debate, but the DoE was sued successfully to start setting standards again.

So there are many reasons for the DoE minimum efficiency standards to be just that, minimum standards. They typically leave lots of room for improvement, which gives manufacturers and installers ample opportunity to upsell where and when they can.

jp_2

well mike,

what is real world? I see afue as an average situation, as in fuel economy. I'd like to know exactly what afue is, I do not see why it can not be exact, it's somewhat simple.

put in 1000btu's of gas, measure temp and volume of output(boiler), thats efficiency.

can't control or measure anythng else, its up to the contractor.

what are you reading, care to post this so we all can discuss afue?

Unknown

If you have a well educated and informed public, the free market can work.

That is not the case in most fields however. Do you think most homes are built "code minimum" because someone has done a cost-benefit analysis of ANY kind? I would say, OBVIOUSLY not, since when I run the numbers, payback is proven again and again and again on efficiency upgrades. Especially when you are comparing initial costs, and not replacement costs!!

Regulations are a stop gap measure against ignorance. Unfortunately, they are often generated from ignorance as well, so they are far from perfect. But I say with no hesitancy it is not a coincidence that most homes are code minimum, and that it is not in most people's best interests to build a home to code minimum energy standards. Unfortunately, they don't KNOW that.

Folks can only follow their best economic interests if they have perfect information about what is actually in their best economic interest.

Plus, what is in a builder's economic interest is to build as cheaply as possible. In many areas, you don't get to choose what you want; choose a building style from column A, siding from column B, fixtures from column C, and there is your house. Builder owns the land, makes the rules, and you play or go somewhere else... if you can.

This is not in the interest of the consumer buying the house except in the sense that the option is better than NOT living in the area they are trying to get into, perhaps. That is not in the interest of the country that must must MUST reduce reliance on foreign energy. It's in the interest of the builder, who has no economic incentive to care at all about the impact of the home he is building.

So brad, with all due respect, exactly how do you figure the "free market" will shake this out, until energy is so expensive that people actually have to move to areas where developers don't own all the land available for building? How will the free market help Joe Accountant building his home who has no idea what it will truly cost to heat using option A vs option B?

I am a capitalist at heart, but it's got limits my friend. I'm not saying a 90% efficiency heat source should be required in every home, but I am saying there is a place for regulation here. Perhaps regulation targeted at investment homes would be a good start, to rectify the situation of a builder having no economic tie to the energy performance of the home they are building, unlike an owner-builder contracting their own home. I don't know. But SOMETHING is needed, for sure.

Mike T., Swampeast MO

See this Official DOE Document (in many other places as well) for this definition of AFUE:

"The DOE test procedure defines AFUE as the heat transferred to the conditioned space divided by the fuel energy supplied." [emphasis added]

Parts of US DOE Regulation 10 CRF PART 430

This should be a link. If it doesn't work you Google with 10 CFR PART 430

Am specifically and currently studying Appendix N to Subpart B of Part 430, "Uniform Test Method for Measuring the Energy Consumption of Furnaces and Boilers".

and

Appendix O to Subpart B of Part 430, "Uniform Test Method for Measuring the Energy Consumption of Vented Home Heating Equipment".

Of course these two sections continually refer to other sections as well as ANSI/ASHRAE Standard 103-1993, "Method of Testing for Annuel Fuel Utilization Efficiency of Residential Central Furnaces and Boilers". I'm not a member of ASHRAE and I can't seem to find this document--maybe someone can help...

It seems rather strange to me that the ACTUAL testing methods for a GOVERNMENT STANDARD are not freely available to the public.

I'm not trying to bash ASHRAE in any way, but for a supposedly "independent" association, it's rather difficult to find out much about how they operate. From things I find, it seems that much of their emphasis for change with regards to the testing methods of AFUE come from furnace manufacturers who whine for exemptions and changes because they don't believe some of their products achieve the "number" they believe it should achieve. I know that ASHRAE accepts corporate donations (in fact there's an open position for a coordinator of such), but I cannot find any financial data about the organization--let alone how much of their funding comes from industry.

The whole process of determing AFUE of heating appliances just seems strange. While at essence a government regulation, the true meat is produced by ASHRAE, then reviewed by ANSI, then accepted by the DOE.

Mike T., Swampeast MO

My BIG Problem with AFUE

"The DOE test procedure defines AFUE as the heat transferred to the conditioned space divided by the fuel energy supplied."

There's simply no way this was ANYWHERE near true on a annual basis with my system.

As far as I could tell, my 1970s atmospheric cast iron boiler was operating at its' rated AFUE of 80 in moderately cold weather. VERY important that this assumed that the house (maintained at unchanged TRVs settings for WEEKS) was in fact loosing 85% of that estimated via Manual-J.

A Vitodens with rated AFUE of 94.2 for a difference of 14.2% as added.

The ONLY change to the system was the boiler. Both used constant circulation via a single pump. Both used full outdoor reset--with the exact same curve for one year. Same radiators--same TRVs. Both shut down when the outdoor temp went above about 53°. (Setting on the control was unchanged.) The only two real differences:

1) The old boiler cycled at ±10°F around the reset target while the Vitodens maintained such precisely and exactly any time heat loss exceeded minimum modulation. While this differential was easily measured both by the internal boiler thermometer and surface of the piping before the bypass valve, it nearly disappeared before the supply takeoff to the first radiator (gravity-sized iron pipes). It was completely undetectable at the branch's TRV connection to this rad as well as after two more branch connections to the mains.

2) The old boiler had some constant system bypass via the differential pressure bypass valve. I had CAREFULLY adjusted such for efficiency as defined by least total firing time in a hour of steady, moderately cold weather long after the sun had set.

Yet, on a season long, weather- and indoor temperature-compensated basis, the Vitodens used 43% less fuel. How can this be?

jp_2

well,

sorry I haven't read the doe/afue stuff yet, maybe tonight, theres a ton of stuff there.

my understand is that while the system is running in the 'lab' so and so is its efficiency. heat going to the conditioned space reallly can be just at the boiler output.

in your old system, what was the boiler doing while it was waiting for a 'heat' call? didn't it need to maintain a set temp around the boiler so it wouldn't condense? if so then the boiler would have been running more than it needs, lowering its overall efficiency which in turn makes the mod/cons seem way more efficient? just a guess here, i could be totally wrong.

don't forget too, the old systems ran hotter temps, and its simple to see that to make something higher in temp requires more energy.

also as far as heat loss calcs, some people here say they're dead on, other says they're way off? I use pen & paper and my favorite HP calculator.

so far, it just seems like the 'old' way of running systems was really inefficient? gas,brake,gas,brake....

Mike T., Swampeast MO

Good luck studying that DOE material--I find it quite convoluted. I suppose that makes it much shorter, but it certainly doesn't make it easy to follow.

I took no measures for low temperature protection. Upon purchase there was no bypass and both the burner and the circulator were controlled by a single thermostat. With the addition of the TRVs and constant circulation, the system actually ran a bit warmer than before.

T-T connections were jumped so anytime it wasn't in warm-weather shutdown there was a "call" for heat with the circulator running continuously. Burner kicked in at 10° below reset target and shut down at 10° above. Firing time was remarkably consistent regardless of the weather--right at two minutes, forty seconds. Provided no TRVs were turned up, the only thing that changed was the interval between firings. The only way I could change the firing time was via adjusting the differential pressure bypass valve. This was also a general increase in firing times. I suspect that the thermostat anticipator was improperly adjusted, but I didn't know better at that time and added the TRVs, etc. before I learned how anticipators are properly adjusted.

Via an unmodified Manual-J based heat loss calculation, the boiler was quite oversized, but from what I've seen and learned since, more like "typically" oversized. 100 mbh loss compared to 210 mbh input and 186 mbh output; 167 (or something like that) I=B=R.

Considering that the house had insulation only in the roof when I purchased, with windows and storms in TERRIBLE shape, the original boiler sizing was probably pretty good.

That 100 mbh heat loss is based on the house in completed state. For the last two years with the old boiler and the first with the Vitodens, all of the exterior walls of the ground floor were in bare studs. There is however 1" solid sheathing, tar paper and asbestos-cement siding, so infiltration really isn't too bad and not much different than the uninsulated with plaster & wood lath walls. 2nd and 3rd floors were completely weatherized and almost completely insulated with ground floor windows restored (but no spring bronze weatherstripping) with good storms.

Now I'm remembering part of how I estimated efficiency with the old boiler--I recomputed heat loss for the current state and used 85% of the value.

I will agree that the "old way" of running the boiler was inefficient, but from all I can tell and measure it was actually an improvement compared to the original way upon purchase. I've worked on a number of gravity conversion systems, seen more, and have yet to see a bypass around the boiler. Those with newer boiler like mine are all controlled the exact same way--those still with the original (yes) or old (say 40s-50s) replacements usually have the boiler firing to aquastat with the thermostat controlling only the circulator. In most cases the aquastat is set at 140° or below and I've yet to see condensation damage in any of these systems.

For my general area (Southeast MO and from what I've seen the St. Louis area) this really is a "typical" hot water hydronic system. Post WW-II hydronics are uncommon with post-1950s quite rare.

Tombig_2

Energy Codes

The city of Chicago drafted and passed an energy code for residential new construction a few years back that was very comprehensive. You can't install an 80% appliance unless the envelope is ice box tight. All duct joints sealed, R-38 cielings, etc. and the inspectors enforce the code. Since it applies to new construction and extensive rehab only, HO's still have options for changeouts.

Although I don't like over regulation by our govt., this one shot and scored in my book. I was tired of watching developers selling Lexus' with Yugo mechanicals. Now at least new home buyers are getting 90+ equipment with a tight house and delivery system at assumedly little extra purchase cost. Force feeding the public by way of the developers works in this case.

On the other hand I've been forced to sell govt. mandated 13 seer AC changeouts with the added cost of evap coil change to HO's who admittedly run their AC only a few times a year. It was easier to give them an option though I must say even heavy AC users usually went with 10 seer.

90+ furnaces and boilers along with efficient SYSTEMS have been easy sells. People readily grasp the concept and usually embrace it even with the added cost. It's kind of like adding that $2000 Blaupunkt stereo to the $50,000 car.

Let the DOE do what it wants. The govt. already played their hand with that paltry $300 tax break for 95% and variable speed. Maybe if it was tripled I might get excited about it. I'll keep edumacating the public one at a time along with the rest of you. And they'll tell two friends, and so on....

Mike T., Swampeast MO

90+ furnaces and boilers along with efficient SYSTEMS have been easy sells. People readily grasp the concept and usually embrace it even with the added cost. It's kind of like adding that $2000 Blaupunkt stereo to the $50,000 car.

BRAVO SIR!!!!!!!!

It's ALL about producing efficient SYSTEMS!!!!!!!!!!

Steve_35

Not all work is new.

> Folks can only follow their best

> economic interests if they have perfect

> information about what is actually in their best

> economic interest.

>


Ultimately, what's in someone's best economic interest is their decision, not yours, mine or the government. I offer 3 options in most everything I quote. I quote work only after a fairly extensive comfort survey because I need to determine where the client's interests, concerns and needs lie.

Your point about new homes is well taken, but the majority of equipment sold in the country isn't for new homes. It's replacement equipment. Even in the case of new homes most equipment sold is FA not HW. The traditional problem with FA has been the delivery system and changes have been made in the code to address that. At a minimal cost to the end user.

Unknown

It is their decision... problem is, the free marketeers like to pretend that people have the information needed to make their decisions, and frequently they don't. Maybe in 50 years when you can wave your internet wand where-ever you are and get good professional grade information on any topic at any time quickly and easily, it would work. Today, it does not.

You just proved my point anyway; why does it take changes to codes to address the problems with delivery systems for FHA? I thought the "free market" was supposed to take care of that?

Steamhead (in transit)

The \"market\" in that case

consists of penny-pinching developers and builders who have no stake in the energy efficiency of the houses they build. So they hire the cheapest subcontractors and buy the cheapest possible equipment- is it any wonder these houses are thermal sieves? You couldn't pay me to live in such a house.

Given that business model, it would take regulation and enforcement to force any positive change.

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Constantin

Bingo!

Among other things, the minimum efficiency regulations address market failures, such as the one you describe. A similar scenario erupts in the rental or leasing market with a owner who buys the stuff and a renter/lessee who pays for the operational costs.

Also remember that one of the aims of these standards was reducing the demand for energy... for which it has been a resounding success. That means fewer power plants, switching stations, pylons, and other investments that society was able to forego. Never mind the security implications of importing fuels, etc.

Properly written, standards provide a level playing field for everyone. Plus, they are generally not allowed to eliminate user utility or specific types of equipment. "Niche" equipment may be exempted (see the older CAFE rules for pickups and SUVs, for example), or the rules may be adjusted to allow varying levels of efficiency requirements by equipment class, capacity, etc.

Plus, applying appliance standards on a national basis is generally the preference of manufacturers. Regional standards in places like CA may present a logistical nightmare...

For example, IIRC, four states in the SW (NM,AZ,UT,NV?) had four different standards for toilet flushes... that's where the national 1.6GPF standard was born. After some hickups in the beginning, it looks as though this program has also turned into a success.

jp_2

short cycling?

2 min 40 sec seems like short cycling? how often did the cycle, cycle? doesn;t even sound like all your water got through the boiler before it stopped?

your old system sounds like my neighbors, beautiful old(1860's?)victorian. boiler has no p/s but a bypass ball valve, one pump, no zone valves, house seems to have consistant temp throughout.

if i recall right, as i was looking at it once, it did cycle for waht seemed like a short time.

if there was a way I could convince her a 43% savings, I'm sure she would consider a md/con. that could be why i pushed you so hard for exact data & methods? maybe?

jp_2

confusing,

mike this is a bit confusing to me:

"" "The DOE test procedure defines AFUE as the heat transferred to the conditioned space divided by the fuel energy supplied."

There's simply no way this was ANYWHERE near true on a annual basis with my system. """"

I see the upper statement as simple efficiency. I still haven't read through the whole DOE stuff(20 pages i copied) but it seems they are going towards the way of eff. ratings for DHW heaters?

guess i don;t understand where this goes wrong for you?

it would be far simpier if hey just gave a energy in vs energy out. annual fuel est. is just a big average!

Mike T., Swampeast MO

Time between firing cycles was directly related to the weather--the colder the shorter the interval.

I've never seen a definition of a "short cycle" but I do believe that 2 min 40 sec is certainly at the short end of any reasonably definition. In the original configuration (no bypass, no TRVs, burner & circulator controlled by single wall thermostat) firing time increased with decreasing temperature but was typically less than a minute.

Interesting comment about the "all the water not getting through the boiler before it stopped". With about 225 gallons in the system and the B&G 100 moving about 27 GPM in the wide-open system (before the TRVs) that would have taken about 8 minutes. I can assure you that the system NEVER fired for that long unless the thermostat setting was raised.

At such a high flow rate however (even given the huge piping), some of the water that began in the boiler should have reached the supply connection to every radiator in around 10 seconds. Remember--with gravity systems it's hard to find much temp variance in the supply piping even with the temp changing radically in the boiler. The returns are a true lead anchor. If you call for "more heat" by raising a thermostat, it takes a LONG time before you find an increase in the return main temperature.

Mike T., Swampeast MO

re: Your Neighbor

Properly install a mod-con (even without the TRVs that I consider the BEST part of a MODERN gravity conversion) and energy reduction of that magnitude is nearly guaranteed. No need to take just my word. Search here--you'll find LOTS of substantiation.

Remember--my savings with the mod-con were after the TRVs, reset, constant circulation, WWSD, that had already increased efficiency compared to the original state. By my calculations 57% savings was possible in a perfect world where EVERY btu produced by the boiler goes to the system--I've achieved about 53% so far...

Mike T., Swampeast MO

Have fun jp.

You'll see that the DOE stuff is HIGHLY concerned with ANNUAL. After all the "A" in AFUE stands for "annual". In fact it seems to me that the DOE provides the "annual" portion of the test with ASHRAE giving the "FUE or fuel utilization efficiency". By "designing for the test" it [appears] that forced air manufacturers in particular can effectively negate the "annual" calculations made by the DOE.

Beyond this crap again consider what this is saying to consumers:

That AFUE number is the efficiency that is expected on an annual basis!!!!

Jim Davis

DOE testing is Bogus!!

The Dept of Energy does not test the output of anything. They use a calculated combustion efficiency only and then add theoretical plusses & minuses to come up with a even bigger miscalculated AFUE!! It doesn't matter what efficiency equipment is rated if it can't deliver!! Anyone that has measured real furnace performance in the field has seen that most 90% furnaces don't even deliver 70% and some even below 50%.