Mod-Con vs. cast iron

Unknown

Bless you.

sidney r. bray

modcon vs cast iron

I'm a h/o debating whether I should spend an extra $2000 to invest in an Ultra vs Cast Iron boiler (I have a leaking cast iron WM now). I know the efficiency is greater by at least 10% in the Ultra plus the modulating factor would produce other savings but any idea how long it would take to re-coup the $2k in cost with savings in efficiency with the Ultra? I'm thinking of adding a wood pellet stove as a back-up irregarless of the primary heat source. I'm nearly all standing cast iron radiation and about 1434 sq.ft well insulated home with some in-floor in bsmt and provisions for more heat in the bsmt with cast iron radiators. Any ball-park guesses on how many years it would take to re-coup the extra costs??

Mike T., Swampeast MO

Your system sounds like it has MUCH to benefit from a condensing/modulating boiler as it should be able to operate at quite low temperatures.

Properly installed and adjusted, experience has shown that condensing/modulating boilers use significantly less fuel than implied by the difference in AFUE between them and conventional boilers. 30%-50% reduction in fuel consumption is very common.

Sorry, but I can't estimate payback--too many variables.

If you do integrate a solid fuel boiler into the system, please have such done by a true expert who is familiar with such integration with the type of boiler you choose!

Dave Yates (GrandPAH)_1

ROI

If you calculate your annual operating costs over the next ten years with a factor reflecting fuel cost increases and then divide the total by 10, you'll see an accurate representation of average annual fuel savings. Divide that average annual fuel saving number by the $2,000.00 investment and you'll be looking at the ROI (return on investment). Chances are, you'll be looking at a ROI the stock market would be hard pressed to match. Bear in mind that this is a tax-free ROI & it looks even better.

If, on the other hand, that same $2,000.00 were put in the stock market and calculated using the "pay-back", no one would invest in stocks!

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Wayco Wayne_2

Cast iron radiators

love condensing boilers. I have seen 50% savings and more on some of my cast iron radiator jobs. Happy customers make me happy. WW

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ABD

So will the OP still have that $2000 at the end of the ten years, just as he probably will if investing in stocks?

Inquiring minds want to know.

Ron Schroeder

Plumb Bob

Seeing that you appear to be one staright and square shooter In will say that depends, however he/she will at least have $2000 worth of goodies that they wouldn't have otherwise;-)

Dave Yates (PAH)

Well..........

Unlike "real" stocks or bonds, this investment will keep his family warm. You could always buy a wood stove and burn the stocks & bonds for warmth.

But, don't forget this. Real estate has historically been the best investment and the higher eff appliances will add value to the home. If they sell in ten years, then yes - they will still have the OP - only at a nicer return than the 2K in stocks or bonds.

And, all the while they can feel good too because they'll have reduced their carbon footprint and helped lessen global warming.

it's a win/win/win scenario.

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jp_2

est pay back,

well mike you kind of did it.

if he takes last years fuel bill, cuts 30%, that could have been last years 1st pay back, then why not just double it and get 2 yrs pay back.

Its impossbile to do more than est payback, else you got a direct line to mother nature on future weather reports.

ALH_4

I like that idea

If you're looking at a pellet stove, why not buy a pellet boiler? The Windhager boilers looked nice, but I never got to see one irl because of some difficulty with importing due to controls or something. They were also pretty expensive in my opinion, however they did look to be the same thing as the Vitolig. Wouldn't a Vitodens with a Vitolig next to it be a beautiful sight?

-Andrew

Perry_2

I asked the same question a while ago

This is not a question of installing the modcon and cutting your fuel bills in half.

It is a question of paying "X" amount to install a boiler that will cut your fuel bills by perhaps 1/3

Or paying "X + $2000" to cut your bills by perhaps 1/2.

The difference is that by spending the extra $2000 you would cut your bills by perhaps an additional 1/6.

I have heard reasonable argements that a properly sized mod con with all the right controls can cut 20% or more from a conventional boiler. This came out in my personal thread on the subject.

The answer varies greatly on what size boiler you need. If you need a small boiler - then the smallest modcons may be too large and you loose some on what can be done as it cycles on and off (even at minimum firing rate). If you need a larger boiler where the modcon will be running almost contiunuously you can do better than 20% (maybe reach 30% additional savings).

How much extra do you spend to get that savings; is it worth it?

A mod-con is not always worth it.

I wish you luck finding this out.

I should know shortly how things are going to work out for me as I am checking one last option.

Perry

S Ebels

Sid

From reading your thread, it sounds like a condenser would be ideal for your system. M/C boilers LOVE high mass and low temp water which is very often all that is needed with a constant circulation setup.

The least verifiable reduction in energy consumption I have seen is an actual 27%. This is based on actual fuel use not dollar for dollar. Most of my customers that keep track are reporting solidly in the mid thirty % drop in fuel use. As in for every $100 they wpent on fuel, they are now getting the same heat for $70. Twenty% would be a very cautious estimate in my experience. When you factor in the lunatics in the Mid East or another hurricane or even just a 4% annual rise in fuel prices the return looks pretty good. Along with that are environmental issues that few consider and fewer yet seem to care about.

To me, seeing this stuff every day, it's not a matter of if to use a M/C boiler, it's which one.

S Ebels

Sid

oops........sneezed

sidney r. bray

mod-con vs cast iron

For the record, my heat loss is calculated at about 100,000, I was considering the 105 Ultra...the pellet stove would be free standing on the main level of the home..I just want a back-up should I have boiler problems or to take the chill out of the air in our living room (which is part crawl space). It sounds like most responses seem to indicate about 30% savings over the cast-iron which seems inviting, its just $5200 vs $3200 is a big deal if you're budget is a little tight and the mod-cons seem to be more prone to dirt vs the cast iron...I'm still debating, someone convince me.

[Deleted User]

Bite the bullet....

First off, if you're getting those kind of prices on the installation, check the background of the contractor. Those prices look EXTREMELY low to me.

Secondly, it has been my experience here in the Rockies that when comparing the installed cost of a mid range efficiency boiler to that of a mod con that the installed price of the two are REAL close, and in some cases less for the modcon. (stainless steel flue versus PVC, no low temp protection requirements etc)

I would have to chime in with the other respondents and say that 30% is the MINIMUM fuel savings I have seen, and the majority hover near the 50% mark.

As Steve said, its not a matter of modcon versus non modcon, its a mtter of which contractor and which modcon. There are a WHOLE bunch of them out there.

Do your homework first and don't just look at price. Look a the WHOLE package. And don't forget to do your DHW with this extremely efficient method as well.

As they say at the Nike plant, "Just DO it..."

ME

Nick Wilder_2

Maintenance free mod con?

When discussing savings due to a more efficient heating appliance everyone seems to ignore maintenance and repair costs. Why is that?

Steve Goldstein_2

I don't think I agree with this

Perry said:
=================
This is not a question of installing the modcon and cutting your fuel bills in half.

It is a question of paying "X" amount to install a boiler that will cut your fuel bills by perhaps 1/3

Or paying "X + $2000" to cut your bills by perhaps 1/2.
=================

Last April I replaced my 25-year-old Utica cast iron boiler with a Baxi Luna HT mod-con boiler. I was trying to decide between the Baxi and today's equivalent of the boiler I was replacing--another basic Utica cast iron boiler. The price difference between the two was approximately $3k.

It was my assumption that a new basic Utica cast iron boiler wouldn't be much more efficient than the old Utica boiler I was replacing. So I wouldn't have expected to see a significant operational savings if I went that route. I would have saved $3k for the installation cost, but nothing over time.

The Baxi was installed in April, so it hasn't seen a cold month yet. But it does appear to be saving me approximately 30% in fuel consumption so far compared to my historical data. I calculated that I would make up the extra $3k in 4 years, based on last years' fuel prices. If fuel prices rise, then the ROI will be even faster.

sidney r. bray

mod-con vs cast iron

Like Steve G said, my existing leaking wm he 5 cast iron boiler was rated at 82% eff, the new one to replace it isn't really any more efficient, however if you go to the mod-con it seems your overall savings could be in the 30% or higher range over the same size of new cast iron...my only fear is that they seem more susceptible to downtime caused by dirt in the system and with the older standing cast iron radiators that seems to be an issue along with more expensive parts to repair the mod-con..you have to weigh the whole package and anticipate as much as possible. As far as installation costs in this area..that was by best quote at $5.2k on the Ultra, however the cast iron quotes were all pretty close at around $3.2k...they seem to be fairly reputable as an installer based on some feedback I've gotten from end users.

[Deleted User]

Nick Wilder...

Now there's a name I've not seen in a long time.

It is recommended by GAMA that ALL gas appliances be serviced and tested annualy, therefore, I don't view it as being an additional expense.

If we were in Germany, we would be REQUIRED to have our appliances tested annualy, without reprise or recourse. And, if said appliance is found to be defective or in non compliance, you have a VERY short window in which to get it repaired, and if you choose to ignore their demand, they have the authority to come back and REMOVE the offending appliance.

We're finding that under normal operating conditions, that the mod/cons will need a good cleaning and combustion check about once every two years. So, that knocks about $75.00 off of your annual fuel savings for service. Hardly a deal breaker. Plus as Dave yates so elequently pointed out, it IS the right thing to do to reduce your carbon footprint upon the World...

When are you going to trade in your fire breathing dinosaur for a new mod/con Nick? Knowing how you document every cubic foot of gas consumption, I'd think you'd be jumping on this band wagon a lot sooner:-)

ME

Unknown

If your load is really that big, this is an absolute no-brainer. Even a moderate increase in efficiency would generate signficant savings.

One thing no one seems to mention is that mod/cons are also either silent or very, very close to it. Personally, I'd pay a premium just for that.

sidney r. bray

modcon vs cast iron

Yes, the quietness of the unit is a factor I've been considering since the boiler actually sits almost directly below our master bedroom, our existing cast iron boiler is on the noisy side...I guess the key will be that the Ultra is properly installed and routinely maintained..there will be a strainer installed & balled off on the return side so that I can clean the larger particles that may accumulate annually...most of the feedback on the Wall seems to indicate that the mod-con is the right decision, irregardless of the higher initial cost..

Mike T., Swampeast MO

Just don't get too large of a boiler. I'd truly have that heat loss verified as it sounds rather high for the square footage.

If so high partly because of poor insulation/weatherization, I'd HIGHLY suggest that you insulate/weatherize as much as practical given the construction and other concerns like historic value. From your email address it sounds like you might be in "way north" Michigan with bitter cold weather...

Heat loss calculations tend to be extremely generous with the actual heat required to maintain space temperature at design conditions overstated by at least 30% and typically more like 50%. For that reason, many (including me) believe it better to use a boiler that seems a bit small "on paper" than one that is oversized based on the loss calculation. This keeps the "modulation" part of "condensing/modulating" more effective as ALL mod-cons have a definite low limit of modulation and that low limit increases as the boiler size increases.

S Ebels

Thanks Noel

Nice to know someone cares.

S Ebels

I'll second that

In EVERY case where I have installed a boiler with input sized to a heat loss calc I have found that it could have been a size smaller.

Couple examples:

We did an emergency changeout of an atmospheric boiler that was serving an adult foster care home. The existing boiler was 215,000 IIRC and had failed in a big way. Think 2" of water over 1,600 sq ft of basement. With 18 old folks upstairs that like it 76* and the OD temp running in the teens, the owner said put in whatever you have......NOW!. The only boiler I had on hand was a Buderus G-124/32 which fires at 132,000 btu's. After explaining that we would change it to a larger size later we installed it and fired it up with the interior temp at 58* and all the residents under blankets. It was Saturday morning about 2:30 AM when we lit it off. I came back Saturday noon and found that the 2107 control indicated that the burner had run continuously since it was fired up. The OD temp had dropped below zero that night so the reset was calling for max temp, which I had set at 185. While there it finally satisfied the aquastat and cycled off. I told the building owner that we had just given the boiler about all it would ever see as far as load goes and it had met the demand. I ran a heat loss of the building (an old house with about 4 or 5 additions), and came up with a load of 145,000 or so at design. The output on the Buderus is only 110,000. That was 3 winters ago and it has kept the place warm and toasty ever since through all kinds of sub-design temps. The owner told me that her fuel use dropped by 20% to boot.


My son in law and daughter built a new house two years ago that has 6,200 sq ft of living space in it. They insulated it very well (dad helped with building design) and used good windows but a lot of 'em. The heat load for the house came to 106,000 so I selected a Viessmann Vitodens 8-32 which has a max output of 101,000 on LP gas. After a couple winters of living there, it's very apparent that a 6-24 with an ouput of only 73,000 would easily heat the house. Even at design temps (-6*) the 8-32 barely runs above an idle. HVAC Calc indicated a heating load of about 17 btu's per sq ft and it's plain to see that it actually runs around 11-12.

Perry_2

Your 25 year old boiler would have been

about 60% efficient when it was built. It would have less efficieny if significantly oversized - which was typical of back then.

A more recent cast iron boiler would be in the 80% range. Properly sized it would have been better than your old boiler in efficiency.

So you are not comparing apples to apples.

I agree that replacing a 25 year old boiler with any ModCon will show substaintial energy savings. It does not compare the savings you could have gotten with a properly sized 80+ % efficient cast iron boiler with the ModCon.

In the case of the original poster to this thread. If he truly needs 100,000 Btu/hr - then I agree the case for a ModCon is strong. But, you also have to consider how much piping rework or other things will be needed to retrofit it to their system. Sometimes this is simple, sometimes a little work, and sometimes a lot of work (and work is not cheap).

Please be aware of the controls that will be needed to really optimize the boiler efficiency. The Vitodens 200 has this built in. I am not aware of any other ModCon that really has a comprehensive control program that can be adjusted to match the house and heating installation. The other ModCons have much simpler outdoor reset options; and while an improvement over conventional - not the best either.

In my case, I "need" a boiler about half that size. The best place to direct vent a ModCon is half way accross the basement - which will require piping changes ($$$). Due to available ModCon sizing I figure the boiler will cycle on and off for 4 - 5 months of the year, and then run relatively consistently about 3 months of the year.

Right now - now that I've got my first quotes in - I'm not so sure that in my case that it will be economical to install a good ModCon. I am still persuing a couple of options there (and I would like to thank everyone who has helped me privatly via email understand the situation). I should know within a week what I am doing.

Perry

Dave Yates (PAH)

ROI comparison

Perry,

My quotes for heating appliances don't look at the ROI of modcons against the old klunkers, I utilize an annual operatimg cost analysis between the lower eff appliance (80+%) vs. the higher eff (90+%) appliance. That eliminates any smoke & mirror nonsense. THe additional labor and materials are included as the ROI is based upon the installed price and not just the equipment cost difference. In most cases, my customers have chosen the high eff appliance.

One that did not, chose an 80+% eff furnace. Her quote had held the hi-eff options, but the extra $$$ weren't in her budget - or so she said at the time. Two years later, her immediate neighbor needed a new furnace. They chose the 90+% eff model. Not long after that installation, I got a phone call from the 80+ lady. She demanded to know why her gas bills were higher than her neighbors and why we had "ripped her off" by installing a lower eff appliance. I retrieved her quote from her file and gave her a copy of the returned (signed) form. On it was her signature and dated initials next to the options chosen. Now she's mad at herself. I offered her several hundred on a trade-in, but she refused.

In the end, it's your money and your decision to make. Lots of great advice in this thread for you to mull over. Good luck.

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Tony_23

Reality is

A 25 yr old Utica isn't hardly any different in efficiency than a new one of the 80 % variety. I've installed dozens of CI 80 %ers in replacement of CI boilers, both wet and dry base, and have never had anyone notice much difference in fuel consumption. If you can convince me there's a big difference between today's pin style boilers and those of even the 60's, I'm all ears. Ah, the fallacy of AFUE and how it sells equipment

My LOWEST reported savings is above 30 % with W-M Ultras vs 80 % style CI boilers. The youngest was 16 yrs old. The biggest savings was an Ultra 230 replacing two Utica MAGB's from about '84-5 vintage. They are using 1/3 of previous w/o ODR (needed fast recovery). Some of it was from oversizing (300 in vs 230max), and some was from repiping, but most was from modulation and HX transfer efficiency.

Changes in piping are a given when converting to mod/con or low mass, I wouldn't let that deter me from the savings potential. Also, the Ultra can vent up to 100 ft of pipe w/ two 90 ells. I'm not trying to sell you an an Ultra, just passing on info from my experiences. I have zero experience w/ Viessmann so can't actually compare the two fairly.



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Dave Yates (PAH)

fuel savings

Anecdotal evidence from two engineer customers:

* We replaced a steam boiler with a modcon in a tudor-style early 1900's mansion that had a two-pipe steam distribution network to standing CI rads (they and the dist piping remained). The owner claims he reduced energy consumption by 70+%. The steam boiler was less than 20 years old and an 80%-er. The home lacks insulation in the side walls and the windows are single-pane with steel frames. As they move forward with remodeling plans and change the home's heat loss characteristics, the modcon will self adjust. As hydronicians already will know, that modcon isn't always in condensing mode. However, it is for the majority of the heating season.

* A relatively new 80+ CI boiler was replaced with a modcon. Hot water system with a mix of convectors (old side) and baseboard (additions), so this time we limited the bottom end of the reset curve. Another engineer! He too tracked actual fuel usage (not the escallating costs). A rock-solid 30% according to his calculations.

Other customers have reported savings in spite of wild increases in fuel costs, but it's just those two who tracked the fuel usage by comparing the previous year's heating degree days to the new year's numbers to get factual information. My ROI calculations are much more conservative and based upon the AFUE ratings (typically just 12% to 15% better for modcons). The real-world numbers are much better, but anecdotal at best and I don't use them for sales presentations.

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sidney r. bray

mod-con vs cast iron

Regarding my heat loss calculation, I had one of the Wall's frequent contributors (Brad White) help me with the heat loss to which I'm grateful for all his guidance and assistance along the way, we ended up with 62K main level heat loss and 38K bsmt heat loss...I did the Slant Fin design disc at 87K overall..even though my basement radiators aren't hooked up yet they will be shortly..I would hope the Ultra 105 would more than handle what's required, but I'm not sure about the next size down..yes, I'm in the south-central Upper Peninsula near Iron Mountain (home of Steve Mariucci/Tom Izzo)..I appreciate all who have contributed on The Wall...your input is appreciated..I hope the mod-con will serve me well..I'm still getting quotes at this time.

ishmael2k

Fuel Savings

> A 25 yr old Utica isn't hardly any different in

> efficiency than a new one of the 80 % variety.

> I've installed dozens of CI 80 %ers in

> replacement of CI boilers, both wet and dry base,

> and have never had anyone notice much difference

> in fuel consumption. If you can convince me

> there's a big difference between today's pin

> style boilers and those of even the 60's, I'm all

> ears. Ah, the fallacy of AFUE and how it sells

> equipment

>

> My LOWEST reported savings is

> above 30 % with W-M Ultras vs 80 % style CI

> boilers. The youngest was 16 yrs old. The biggest

> savings was an Ultra 230 replacing two Utica

> MAGB's from about '84-5 vintage. They are using

> 1/3 of previous w/o ODR (needed fast recovery).

> Some of it was from oversizing (300 in vs

> 230max), and some was from repiping, but most was

> from modulation and HX transfer

> efficiency.

>

> Changes in piping are a given when

> converting to mod/con or low mass, I wouldn't let

> that deter me from the savings potential. Also,

> the Ultra can vent up to 100 ft of pipe w/ two 90

> ells. I'm not trying to sell you an an Ultra,

> just passing on info from my experiences. I have

> zero experience w/ Viessmann so can't actually

> compare the two fairly.

>

>

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 384&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

> "Find A Professional"_/A_

Nick Wilder_2

Care and feeding of dinosaurs vs. Munchkins.

My dinosaur consumes 1,050 therms per year. At a buck each, going from 70% (it eats mostly outside air) to 90% AFUE would save me only about $239 a year. After paying Advanced Hydronics $75 a year to keep the warranty valid my savings drop to only $164.

Now if Professor E. will install a mod-con in exchange for my payment of $164 a year for life, I will let him in the door next week. How about twice that -- $328 per year?

Deal or no deal?

Steve Goldstein_2

My BTUs

My 25-year-old cast iron boiler (plus the little gas I spent on stoves, clothes dryers, etc.) consumed 1800 BTUs/year on average. My house is a 140-yr-old farmhouse w/ 3200 sq. ft.

A 30% or greater savings will add up pretty quickly. I'll be tracking this data with interest...

Tony_23

A buck a therm?

Wow, NG costs about $ 2 a therm here in WNY (including taxes)

Keep waiting, all that money you're "not" spending right now will be put to good use at the gas co. Their pocket, your pocket. You decide.

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Perry_2

Midwest gas price is

about $1.15 per therm in the last year including taxes and meter charge. I know the gas company claims that it is less - but I figure a therm is what I pay in my gas bill divided by how many therms.

I have 5 years of month by month detailed records of Gas Bill, Therms, Degree days; from which I calculate a "cost per therm." An annual summary is added to the spreadsheet.

I do note that in the summer when all I'm doing is heating water the "real" cost per therm has consistently been well over $2.00 (sometimes near $2.50). Which is why I tell people that if all you are going to use gas for is hot water..... you are better off buying an electric hot water heater. The "meter" charges are usally twice as much as the gas cost...

My question for Tony: What is NY state doing with all that extra tax revenue... Natural gas itself is not that expensive.

Perry

Nick Wilder_2

$1.03 per therm plus metering & billing

Over the past 12 months I paid (Denver area) $1.03 per therm including taxes for 1,007 therms of mixed gas (815 Btu/cu ft). In addition I paid $119 for "metering and billing."

If you are comparing consumption costs between boiler types, then you want to count only the gas cost. The fixed charges won't change.

So you could say that a more efficient boiler raises your cost per therm.

Anyone ever drill a hole into a gas meter and through the bellows? That can really lower your gas consumption. Just don't forget to patch the hole in the meter housing.

John_82

Cast-iron rads & radiant are awesome applications for a condensing boiler! W/ constant circulation on those rads you can keep that boiler condensing all season!! It's a great choice & you'll recover the extra cash it costs in your fuel bill.

Tony_23

If it moves

the state taxes it. That's why they use a 1/2 ft dial here

They probably use it to subsidize the "monopoly breaker" co's that deregulation spawned for "the good of the consumer"

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[Deleted User]

Re: Care and feeding of Dinosaurs...

I think your savings numbers are a bit off, but it's still not enough to get me out of retirement:-)

Someone stole all of my tools, and I had to retire to the office:-)

Now, I know you know how to solder, and what with the internet being what it is, I see NO reason why you couldn't find a mod con on line for cheap and put it in and reduce your gas bill by 30% minimum.

What's a retired bank auditors hours worth these days? Maybe Mrs Wilder would PAY you to put one in:-)

It's your money, spend it wisely...

ME