High Efficiency Boiler Return On Investment

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Old 12-25-12, 08:12 PM
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High Efficiency Boiler Return On Investment

Has anyone actually calculated the ROI or the number of years for payback on a high efficiency boiler?

I have averaged 760 therms annually for the past ten years to heat my 1 1/2 story house in southeastern Wisconsin. At today's prices that is about $800 per year. With a higher cost for boiler and installation, and the potential for higher maintenance cost, how would this be economically justifiable? Now it seems the government will force consumers to spend more money starting in May 2013 for a questionable return on investment. My boiler is a 1987 Vaillant with 80,000 btu input.

Thanks.
 
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Old 12-26-12, 07:37 AM
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A higher efficiency, natural-gas boiler might achieve a reasonable payback if you have to replace the old one anyway because it is shot, and the choice is between a higher efficiency model and another model.

But replacing a functioning boiler with a high efficiency model to save on fuel costs, is pretty much a non starter, payback-wise. Just for grins, assume that you replaced your boiler with a mythical model that used zero fuel. If a new boiler and installation cost $8,000, your payback period would be 10 years. More realistically, the new boiler might reduce your annual fuel cost from $800 to $700, for a net savings of $100 per year. The payback period would be $8,000 / $100 = 80 years.
 
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Old 12-26-12, 10:55 AM
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There is always the fact that you use less depletable resources !!!

I think it's a worth while investment myself. Since you end up with say 95% thermal efficency, and you also get outdoor reset (usually) with the boiler and modulation you would likely say 30-40 percent easily.
Just to go from 83% to 95% is 12%, outdoor reset has been claimed to add 30%, and modulation will save $$$ due to reduced short cycling.
You could save 300 a year or more. Still a long payback yes. At today's interest rates... what does it cost to carry 8000 a month on a line of credit ??? Maybe 300 a year...
This is before prices of gas go up.
 
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Old 12-26-12, 01:51 PM
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At today's interest rates... what does it cost to carry 8000 a month on a line of credit ??? Maybe 300 a year...
What about the $8,000 principle amount? It has to be paid back too.
 
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Old 12-26-12, 02:21 PM
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If you are replacing because your boiler has reached the end of its lifespan, you only need to consider the different in cost between the high efficiency and a traditional boiler. You also don't need to get a mod/con to meet the new government regs.
 
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Old 12-26-12, 05:17 PM
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There is always the fact that you use less depletable resources !!!
Possibly true, but the OP was asking about his economic payback. There are innumerable "green" energy alternatives that could be, are, or maybe should be implemented if economics (money) aren't completely factored into the math.
 
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Old 12-27-12, 11:34 AM
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If my boiler was at the end of its life, the return on investment would not be questionable.

However, when is the end of a boiler's life? All I ever do is have an annual service/inspection. The only parts replaced were two zone valve and a circulator. These are external to the boiler. All boiler controls are standard off the shelf items.

In my thinking, only a leaking heat exchanger would be an end of life event.
 
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Old 12-27-12, 11:48 AM
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In my thinking, only a leaking heat exchanger would be an end of life event.
You and I think alike..........................................................
 
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Old 12-27-12, 12:36 PM
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I worked in commercial and industrial power plants for over thirty years. Many of the boilers during that time were 60 years old or more. The last two jobs I worked the boilers were installed in the 1960s and they are still in use.
 
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Old 12-27-12, 01:32 PM
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When certain replacement parts become hard to to acquire would be another sign.
 
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Old 12-27-12, 03:41 PM
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When certain replacement parts become hard to to acquire would be another sign.
Good point, probably most applicable to newer boilers with proprietary electronics and those European wall-hangers. My older boiler's parts are mostly all generic and readily available - e.g., circulator, aquastat, gauge, valving, gas burner, relief valve, pressure reducing valve, barometric damper, etc.

If the water side of my boiler sprung a leak, then that would be curtains. Well actually maybe not: it is a steel fire-tube boiler, and if a tube sprung a leak where it is rolled into the tubesheet, I might be able to re-roll the tube, seal-weld the end of the tube to the tubesheet, or maybe even try some JB Weld. If a leak developed somewhere in the middle of a tube, I might try to temporarily plug that tube to buy a little time until warm weather.

In some ways, older stuff is easier to work on than the new.
 
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Old 12-27-12, 04:36 PM
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In my opinion you are far better off with a steel boiler. While not a DIY job tubes can be replaced fairly easily. Seal welding of tubes is common and even cracks in tube sheets can be welded. It is the cast iron boilers that are almost always junked if a crack develops.
 
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Old 12-29-12, 04:25 PM
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Furd, are there any residential-sized, steel boilers still being manufactured?

There are some additional materials that might be good in boiler manufacture - e.g., monel and copper-nickel - that seem to be neglected, perhaps due to cost. I'm a bit leery of stainless steel and copper, but I have no personal evidence.

It seems that segmented, cast-iron boilers are now the default standard for residential. I have been satisfied with my fire-tube, hot-water boiler, although in industrial, marine, and utility applications, water-tube boilers seem to dominate.
 
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Old 12-29-12, 05:40 PM
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Honestly, I know nothing about the current state of the industry when it comes to residential boilers. My background is commercial and industrial equipment and even there I can't claim any expertise as far as current practices are concerned as I have been retired for almost nine years.
 
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