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• Member Posts: 14,738
It can be a simple as
efficiency= the ratio of a desired output quantity divide by the necessary input quantity to produce the output.

When applied to a home or heating system
Building
Boiler
Distribution
Electrical
Total system
are some examples where efficiency can be calculated.

All are areas when efficiency can be determined by various math formulas.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
• Member Posts: 15,700
Well... true enough, @hot_rod , in that sense. But it can be misleading, which is why -- particularly with heating systems -- I prefer to not use the term unless one is talking about how much energy input -- fuel and electricity -- is require to produce the desired output. Which, of course, isn't really efficiency either. For example, often one hears someone touting a high efficiency boiler at say 96% -- which is true enough, under certain conditions -- but in reality the overall energy use may be no different from a steam system with a boiler at 84%, if the high efficiency boiler isn't properly sized and controlled.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
• Member Posts: 14,738
I get it, and how many homeowners want or can comprehend the meaning of all the different efficiency involved.

The discussion becomes quite a bit different from what we here on the list communicate and understand and the average, even above average homeowners
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
• Member Posts: 234
Yes, you can discuss engineering efficiency for components such as motors, boilers, etc. Those are different than Thermodynamic cycle efficiency. However, thermodynamic cycle efficiency is not applicable to home heating. The component efficiency of a boiler, as an example, is.

The term "energy efficiency" as applied to "Home Heating" is a relative term and is typically either a comparison ratio of what is happening vs the past (my gas usage reduced so much by installing my Vitodens 200 that the gas company changed the meter because they thought it was defective). I no longer recall the exact number from 2007... However, my memory is that the Vitodens 200 with an indirect hot water heater was about 3 times as energy efficient as the old boiler with a separate gas fired water heater (i.e - used about 1/3 of the natural gas).

Another way "energy efficiency" can be applied is as a comparison to what is reasonably achievable - and it what I think should be applicable to new construction and certain remodels.

In my opinion - there should be standards that say that the amount of energy usage for cooling and heating is X units/degree days/sq ft living area.

Have a great day,

Perry

• Member Posts: 15,700
@PerryHolzman , I'd agree with this ("In my opinion - there should be standards that say that the amount of energy usage for cooling and heating is X units/degree days/sq ft living area.") quite happily -- but only if it applies to new construction or voluntary gut rehabs. And I'd even be happy with a remarkably low value for X. No need for it to be higher.

Where the problem lies is in application to existing buildings, in particular historical buildings. The problem is already there with regard to some other code issues; for example, one of the buildings which I maintain could really use an electrical upgrade (it's safe enough, and everything is to the code which applied when it was installed), but the local AHJ has opined that any significant work (in this case, changing fuses to GFI/arc fault circuit breakers) he would require that all the wiring be brought up to the current code. Can't do that -- so I can't do anything useful. Most historic buildings have this kind of problem in one way or another (ADA access is another area like that).
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
• Member Posts: 14,407

I also don't understand why there are not 40,000- 50,000 Btu max conventional heating boilers and mod/con heating boilers out there.

@PerryHolzman , do you mean Input, DOE or Net ratings?

I found these, in alphabetical order:

Burnham 202E: https://www.usboiler.net/product/series-2-gas-water-boiler

Columbia MCB-50J (a rebranded Utica): http://cdn.columbiaheating.com.s3.amazonaws.com/certificates/2012 MCB-MCC LIT.pdf

All Steamed Up, Inc.
Steam, Vapor & Hot-Water Heating Specialists
Oil & Gas Burner Service
Consulting
• Member Posts: 2,745
Wow. I didn't think that would ruffle any feathers, that surely wasn't my intent. However, look at how it's used, commonly, today. Now, convince me that it's an engineering term. You can see some of it's historical meaning in it's modern usage, but I don't think it can be claimed as technical jargon any more.
• Member Posts: 2,256
Homeowner A:

"I just got a new boiler installed, its 95% efficient! My old one was only 80% efficient, so I should save 15% this winter"

Homeowner B:

"Hey I heat my house with electric [resistance] heat! The electrician told me that its 100% efficient! Cant beat that!"

Homeowner A's heating [gas] bill last winter \$1200, this winter \$750.

Homeowner B's heating [electric] bill this winter \$2800.

The socioeconomic term seems to imply cost-effectiveness or potential savings. Efficiency in the real engineering sense is total energy in/useful energy out.

It seems the general public hears the term "efficiency" and just assumes it means better.
Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
• Member Posts: 14,738
Maybe the word efficiency has dual meaning. A HO/ meaning and a professional HVAC, Plumber Engineer meaning
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
• Member Posts: 15,700
hot_rod said:

Maybe the word efficiency has dual meaning. A HO/ meaning and a professional HVAC, Plumber Engineer meaning

Exactly
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
• Member Posts: 2,745

hot_rod said:

Maybe the word efficiency has dual meaning. A HO/ meaning and a professional HVAC, Plumber Engineer meaning

Exactly
Exactly2!

But the groups using different definitions still act like it means the same thing. Or, perhaps even worse, don't realize that they're talking about different things.

A recipe for heartache, if not real trouble.

• Member Posts: 15,700
Oh quite, @ratio ! But what that means is that if one group is using the term in a sloppy way, or incorrect way, the other group -- us, perhaps? -- has to figure out how to communicate what we know and understand. Not so simple.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
• Member Posts: 14,738
Often just the terms are foreign to someone who is not in the industry or business.
At some point you call on and trust the people that deal with the technology or design.

How far can you get explaining thermodynamics design and engineering to people without the knowledge, background, or understanding of the words being used.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
• Member Posts: 1,181
Checked my gas bill today. 420 units, \$266. \$0.63 per therm. Cheapest. I can remember.

Electric rate... \$0.15/kw-hr on my latest bill at winter rates. I think I used 1100kwhr (have a heat pump for mild weather).

IF i do my math right, thats a COP of 5.5 (19EER) needed to break even if my steam boiler is 79% effecient.

• Member Posts: 1,163
Jeepers, a lot of subjects going on within this one thread; I like it!

I'm going to input a little here about my local situation. NG is not, has never been, and probably never will be an option out here. Oil is all but dead. LP or electric are the purchasing options and heat pump technology is pretty slim. There are a lot of solid fuel burners in place- for example the road I live on is 4 miles long and there are 17 homes on it. 9 of those homes use an outdoor wood boiler, 3 use indoor wood stoves, 4 burn LP and one is all off-peak electric with a 40kw PV solar array in the yard. Our electric provider here is astronomically priced after all the fees and add-ons that come with delivery, so my last bill was almost \$300 for ~650 kWh used and almost half of that usage was from circ pumps in my OWB system. The poor guy that spent \$50k on the PV array will still owe \$40k of that if the array lasts 20 years. At these rates, even GSHP with an average COP of 3 come out very close to the price of a 95% LP system with DX cooling, with historical LP prices assuming 20 year equipment life on both. From a financial standpoint, burning wood is even very close to equal after equipment depreciation, labor intensity, etc. Something sustainable like WtE would be fantastic, if it were feasible but it's incredibly cost prohibitive. Just 50 miles from me, 30 miles NE of the Minneapolis trash burner, lived another trash burner just like it until last year when it was taken out of service. I've been around them both my entire life and never once caught a hint of smell from either plant, and no visible particulate matter from the stacks unlike the coal plant that I can see plain as day from 35 miles away. The funny part is, the NIMBY that got that trash burner shut down don't seem to mind the landfill just a couple miles across town that'll gag you just driving down the highway. My new home I think is still going to get a GSHP system as the design is approximately 10 btu/sq ft and all low temp radiant, but that's merely "just because", not so much for cost savings. Moral of the story here is that fossil free regs may very well hurt a whole lot of people financially if it comes down to that.
• Member Posts: 2,665
If you try to answer the wrong question, all kinds of misunderstanding can ensue.

Even if a homeowner asks what the efficiency of if a proposed heating system is, presumably what he really wants to know what the system will cost to have it installed or the lifetime cost of ownership. Even then one would need to know if he is a builder who wants to make the most profit selling the house, a short-term owner who wants it cheap now, and it can fall apart two weeks he sells it, or a young couple who want to spend their lives there.
• Member Posts: 1,609
How often do we see thermostatically controlled dampers on each register?
• Member Posts: 9,531
edited March 2020
I think our present world wide dilemma (covid-19) has some very large impacts on carbon emissions in a short period of time. Do to shelter in place orders. Unintended benefits.

Pretty hard to argue against its impact, If things can clean up in a 2 month window.

Maybe it’s mother nature’s way of fighting back😉