energy savings---snake oil?

Tony Conner

To A Very Large...

...exent, you're throwing rocks at the wrong guys. The vast majority of the pro's on this board are contractors. Most contractors that I know are NOT big-time into design calculations, but rather rely on government bodies, professional engineering people and/or manufacturers to provide a lot of the information they use. (You can't be an expert on everything, or even every aspect of any one thing.) My personal experience in actually "doing the math" on some of this stuff is that what's being held-out as accurate, is in fact often inaccurate, and occasionally out-and-out wrong. On the one that are "wrong", many if not most are honest errors, or misunderstandings as opposed to some conspiracy. Some are deliberately deceitful though. I suspect that the "40% energy savings" touted by some window manufacturers (mentioned in an earlier message by another poster on this string) originally meant a 40% reduction in heat loss that could be achieved by retrofitting these particular energy efficient windows over the rotten old single pane original jobbies on the pre WW-II house that was the study case. Some folks seized on this 40% as the potential reduction in heating costs for the entire structure, as opposed to just the heat loss through the windows. Most of the people touting these unrealistic savings were just mistaken - but some who knew better deliberately mislead customers, in order to make some easy money. My experience is that if somebody wants to sow confusion in any area at all - political, economic, technical, etc. percentages are THE way to go. Combine percentages with some statistics (remember the 3 kinds of lies - lies, damned lies and statistics), and the confusion generated is pretty much total. Figures don't lie, but liars can figure.

Anybody who isn't thinking for themselves is letting someone else do their thinking for them. And that's risky, because you're trusting that "other someone" or organization to have your best interests in mind. That's not nearly always the case, as has been repeatedly demonstrated throughout history.

Just out of curiousity, Alpha-Omega, how's the level of accuracy and honesty in YOUR business, whatever that happens to be? No better than any other, I'll wager.

jerry scharf

HfH does not use any used parts in any projects

The way it works in my area is you donate items to HfH at a local deconstrcution/recycling company. They sell it to whomever wants it for whatever they can, Most of that money goes to HfH. You get to set the value of the items for tax deductions. Everyone does better out of the deal.

I don't recycle things that I think have reached their useful life or are no longer permitted in construction, but that's my choice.I'm always amazed and amused by what people will buy used.

jerry

Dave Yates (PAH)

same

here Jerry. They have a resale center where we take items like this that have lots of usefull life left in them.

The HfH projects that we've done have had a mix of new and used equipment depending upon what's in their inventory.

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Dave Yates (PAH)

careful ME

Those look like California magnets you've got there!

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Tony Conner

I'm Curious...

... Mr. A-O, exactly what business are you in? Something beyond examination or reproach, I'd assume. You'd have to be,right? Glass houses and all that...Anway, you're kind of throwing rocks at the wrong guys though. Most of these folks are contractors, not the engineering/governmental bodies/manufacturers who generate the "percentages".

In spite of the above, I welcome your challenge of calculations, efficiency numbers and statistics. If nobody ever stands up and says they disagree with something, any forum just turns into a mutual admiration society. Anyone who blindly assumes that others have necessarily accurately determined or calculated - pretty much anything - with your personal best interests at heart, is very often in for for a nasty surprise. Most often this surprise is due to an honest error, rather than any particluar malice. However, intentional deceptions happen often enough to be a serious concern in any area of life.

My experience with statistics and surveys in general is that they very much tend to reflect the predetermined beliefs/values of the people funding the adventure. Percentages can be very deceiving - someone else has picked the formula (very often more than one formula can be applied to a given problem and that gets compounded by the fact that there are almost always assumptions - conservative or aggressive - that must be made), and done the calculation. The more complex the forumula, the more room for error, or manipulation. Often, just the simple questions "Will you show me how you calculated that?" and "Exactly what assumptions did you use in your calculations?" generate some impressive stuttering/sputtering, or (my favourite) "It's very complex - you wouldn't understand." I LOVE that one.

Very often when you get to the core of some cherished numbers or information, it turns out like the Dilbert cartoon: "Tomorrow, a doctor with a flashlight shows us where financial projections come from."

Lurker_2

re:

Its funny, this is such a classic newsgroup thread.
Some choose to answer a poorly framed question, others choose to complain about the wording. [sigh]

I'm going to ask my previous question again in another thread to see if anyone wants to answer it.
I personally don't think AO intended to insult anyone here, he just forgot the rules of newsgroup posting

scrook_2

The BTU's

to reheat the house must be replaced but the BTU's lost while the house was a a steady state warm condition vs. a steady state cool condition (lower delta T in to out) are no longer needed, so if the setback period is longer than the time required for th ehouse to cool to the setback temperature than energy is saved. For an extreme example, imagine you set back the temperature 10°F for an *entire month* -- in that month your fuel consumption will be lower than it would have been had you not set back, in the same way, though to a lesser extent, if you set back 10°F for 8 hours and it took 3 hours to cool 10°F you'd still save some fuel -- the colder it is outside the more you'll save (and the faster the house will cool to the setpack point).

Beware too in clocking the gas meter and tracking degree days at *your* location, at least hourly, if not less or even continuous integration, that the BTU content may vary a few percent month to month, so check your gas bills for the month's average Terms per hundred cubic feet (CCF), and unless the structure is very tight if there are differences in wind velocity you will have slightly different heat losses.

I set back some at night not only for fuel savings (which I have not attemped to quantify, but also because I find is much more comfortable to sleep when it is cooler.