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Are oil-fired, condensing boilers worth it?

Its one of the only true condensing oil fired boilers out there, and Veissmann is one of the only ones that has a control strategy to make it condense.
None of the boilers will condense unless they have good enough controls, and are piped in order to condense.
With baseboards only it may not be worth the higher cost, to buy a condensing boiler.
I d believe its always still worth it to buy something like Buderus or a boiler that can be consistantly in the high 80's. And always worth it to have good controls and things piped right for outdoor reset. The boiler is just the biggest component in the system, so don't overlook the other items too much. The system is only as good as the weakest link.



  • Are oil-fired condensing boilers worth it?

    Hello--so glad I heard about this site. As a homeowner it's great to see a place where there are other homeowners and professionals who enjoy what they do enough to help others out.

    Well, now for my questions. My wife and I just bought a house in Massachusetts where from the start there was no secret that the original, circa 1969 "can" boiler would need to be replaced (the expansion tank actually let go during our first viewing of the property--that is, broke free of it's mountings, crashed onto the boiler, and rolled across the floor. It also knocked a few g's off the purchase price...)

    It's a hot-water loop baseboard system, which also provides the water-heating for the house. The boiler is oil-fired.

    My questions below are related to hardware only, with the assumption that I take the time to find the right company to install it properly (which I'm treating as a project in
    itself, having read that moderate equipment installed properly trumps the best available installed incorrectly...)

    1. I was considering the idea of replacing with an oil-fired condensing boiler (not as common as gas-fired, but seemingly not unheard-of) in the hopes of saving money in the long run. However, as I've looked at energystar's AFUE ratings for oil-fired boilers, it's hard to tell (beyond brand name and additional research) which boilers are condenser-type and which are non-condensers. I was surprised to see that the condensing-types such as Veissmann, Buderus, etc. only seem to squeeze an extra 2% or so above the AFUE 85% minimum on their oil-fired models, which many non-condensing boilers seem to meet anyway. Is it correct to assume that oil-fired condensing boilers are not worth the extra cost of purchase, installation and (potentially) maintenance, or is there more to these units than just the AFUE rating?

    2. Second, if anyone believes an oil-fired condensing boiler does make financial sense, I'm wondering what I could reasonably expect in additional purchase and installation costs if I go the condenser-boiler route, installed by someone who does it right, rather than
    replacing with a high-quality non-condenser type boiler. I realize there are numerous variables involved--I'm just looking for a ball-park guess.

    3. Lastly, if I still go the condensing route, I would welcome any brand input if anyone has any favorites in terms of longevity and reliability (sure, okay, I suppose performance too). Ultimately, for me, it's an issue of cost effectiveness (my apologies to conservationists), so a unit with stunning energy efficiency numbers is not appealing to me if it winds up costing more in service calls.

    I really appreciate everyone's time and input...

  • we don't have

    The low sulpher home heating oil available here yet, to run the super efficient oil burners, but it may be coming soon, they now have low sulpher diesel for super efficient cars and trucks, so maybe low sulpher home heating fuel won't be far away? Thanks, Bob Gagnon

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  • John@Reliable_14
    John@Reliable_14 Member Posts: 171
    Mike, look into ..................

    cast iron three pass boiler oil fired boiler, more bang for the buck.
    Many different brands out here, but the install and other upgrades are the most important part of any job. Was just looking at the Wolf oil fired condensing boiler but was turned off by warrenty, or lack of one (only six years).
    P.S. What part of MA? I'm close to the Cape, Good luck John
  • David Sutton_6
    David Sutton_6 Member Posts: 1,079

    Mike you need to look into the New Buderus G125BE boiler, 89.5 % eff non-condensing With a Low Nox burner, very nice product, the installer has to be certified by buderus. i will be installing them here in western mass.

  • Wild Rover
    Wild Rover Member Posts: 41

    I agree with David that the Buderus is a great piece of equipment. In my opinion the best bang for your buck. Where in MA are you?
  • Buderus and sulpher content

    Good to hear about the Buderus--I've heard the Brits have rated their Bosch condensers among their most reliable, and I believe Buderus (part of Bosch group)is the U.S. version. About Bob's response below, do you know if Buderus' oil-fired version can use regular home heating oil, or is the sulpher content an issue? Perhaps location is the issue--this will be for a home in Abington, MA (Southeastern MA)so the oil standards for the area will prevail. I'd like to avoid a nat-gas conversion--that whole issue seems to be a rat's nest in and of itself, and may not be worth it, but in Abington it is an option, even if it's not the best one.

    Thanks again...

    Again, thanks for your quick replies!

  • Hi Bob, thanks for your quick reply. I wasn't aware of the sulpher issue--I suppose this is a regional thing and something you don't find on the manufacturer's websites. So my understanding is that, as far as you're aware, the home heating oil we get around here (Southeastern MA) pretty much rules out the oil-fired condensing boilers currently on the market?

  • Thanks, John, I hadn't looked into these, but certainly will add it to the research. Sure is nice to be doing this in March instead of January!
  • bill_97
    bill_97 Member Posts: 172
    2 I know

    are the Peerless Pinnacle and the Monitor FCX . Compared to modern 3 pass boilers , these come with a hefty pricetag for the parts alone and you need special venting material for the Pinnacle . I don't know of anyone who installed the Pinnacle . Ken Secor ( a Wall Icon ) has an FCX in his home and loves it , although he did have some burner troubles this past winter .

    I'm not sure how long the payback would be if you went condensing over 3 pass , but I'd guess it'd be a quite a while . Some traditional pin style cast iron boilers have very good AFUE numbers too . My Peerless WBV3 is rated at 87.5 % . Good luck on the search Mike .
  • I don't think

    We have low sulpher home heating oil in the country yet, at least that's what I have been told. I read an article recently about low sulpher automotive fuel,just now becoming available, so maybe the heating fuel will be next.
    Thanks, Bob Gagnon

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  • bill nye_3
    bill nye_3 Member Posts: 307

    There isn't as much latent heat in the flue gas with oil heat. You can 87% with non-condensing , you can only pull maybe 2 or 3% more with a condensing oil boiler. But then you need to be running return water below 120°.

    What type of heat emmitters will you be using? Will you have cool enough return water to make a condensing boiler worthwile?

    There is more water or moisture in the combustion of gas. That is why they can pull more heat out of the flue gas than you can with oil heat. Even then you need low return temperatures.

    You could possibly use hard water as an analogy with high sulphur oil. When you condense it, you leave all the crap behind. This will foul the secondary heat exchanger. It will require more maintainance.

    Spend the extra money on better windows or more insulation. Go with any of the three pass boilers and do the outdoor reset.
  • ed wallace
    ed wallace Member Posts: 1,613
    oil condenising boiler

    if you are looing for a good installer john @ reliable is near you you are kind of far from me i am in watertown
  • Darrell
    Darrell Member Posts: 303
    Ultra-low heating oil

    We had ultra-low sulphur heating oil this winter here...less than 15ppm...and it gave us fits. Not sure if the sulphur content was the culprit or something else. Burned up pumps, blew seals, plugged nozzles, failed check valves, wouldn't light at subzero temps, separated in the tanks...supplier went by to Jet-A. It is coming...but it ain't perfected yet.

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  • Darin Cook_5
    Darin Cook_5 Member Posts: 298

    The Buderus G125BE is not a condensing boiler. That is why they give it a 89+% afue. In a G125 almost all of the combustion takes place in the ceramic burner tube. The burner tube has engineered recirc holes so the combustion is VERY complete and virtually sootless ( a few wisps of dirt on the bottom of the boiler after a season). The majority of the heat is transferred radiantly to the boiler sections. The flue gas exits the burner tube at about 800'F and then runs the 3 pass gamut which has 8 baffle plates to slow the flue gases down and the flue gases finally exit the boiler at about 300'F. If you have an exterior clay tile masonry chimney, you should line it with a stainless steel liner. The beauty of this design is that efficiencies for the boiler stay the same as on day one and the same on year 20 plus. This boiler/burner design pushes pin type boilers into the dinosaur category.

    Buderus does have multiple GB 125BE's running in test homes in the US. They will see how they perform and then go for the UL listings and such. There is some special engineering that goes into these boilers but I do not know the details of it. It sounds very promising though.

    The sulpher content of our oil does not effect the combustion process. The real problem of our oil and combustion lies in when the flue gases get out into a masonry chimney, condenses into sulphuric acid and starts eating away!

    It is a great time to be in this industry, so much new technology, a great time to help our country towards energy independence!!!


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  • Thanks for the input, Ron! I noticed that the Pinnacle and the Monitor were the only ones on Energystar's oil-burning list that had AFUE's in the 90's...and as I'm reading on it seems I was mistaken in my assumption about a number of these being condenser-type. It's looking like a three-pass is making a lot more sense as long as I'll be burning oil.

  • Thanks for setting me straight on the Buderus, Darin--not sure why I just assumed these were condensing-type (no secret that I'm new to all of this). I do have a masonry chimney (which, judging by the existing boiler, will need a good going-over and probably liner as well) so I'll be on guard against anyone suggesting a quick'n'e-z boiler-swap. I do appreciate your input!

  • Thanks for the heads-up, Darrell!

  • Thanks, Ed!

  • Hi Bill,

    I think I'm seeing the writing on the wall here (sheesh, no pun intended...honest), and it's looking like as long as I'm burning oil, a condensing-type boiler isn't worth it for my budget--so now it's a matter of choosing which three-pass to go for. I've had a few nods for Buderus (here and elsewhere), and one for Weil-McLain (as a company...not sure if they do three-pass). The system is the original hot-water baseboard loop, I'm not sure what the return temperatures are. I am considering switching to hot-water radiant floor heating down the road, which I understand uses lower temperatures all around. Whether or not this is a good idea may be another whole topic, so maybe I better just do one thing at a time, unless that move would affect my boiler choice right now...

    Thanks again for your input, Bill...

  • I appreciate your input, Bob--nothing like avoiding a headache down the road!
  • Uni R_2
    Uni R_2 Member Posts: 589
    It will be...

    Why not pave the way? The savings could offset the payment difference on financing the difference. Setup with full ODR you'd save a lot that just the condensing while heating at lower more comfortable/economical temps, maybe get you a third of the way closer to 100% from a regular 3 pass boiler if running a set temperature.

    If I were buying an oil boiler, I'd have given serious thought about Peerless (Hovel is the company that makes it in Europe).

    Price in the 10 year extended warranty option just in case...

    Could be cheaper venting, no protection needed, and definitely would feel better if oil ever went crazy.
  • Glen
    Glen Member Posts: 855
    don't rule out a Vitola -

    with either the Viessmann chassis burner or the Riello. There's good reason they are king in the arctic - where just last week fuel oil was 2.05 a liter in Inuvik, NWT (low sulpher). Robust construction, ease of tune and yes they are competitive relative to efficiency as well. Your main criteria should always be the skill and familiarity your installer has with the equipment - I might be stuck in the Big V rut - but there are other boilers worthy of consideration as well. But back to the condensing oil idea: I must agree that the latent heat available is not yet sufficient to offset the cost of the condensing oil fired boiler. That said oil is $3.90 USG in Eureka MT - which I think by next year will look like a bargain.
  • Tony_23
    Tony_23 Member Posts: 1,033
    Check out

    Check out Dynatherm, too. One of the oldest, and best (IMO), 3 pass boilers made in the States.
  • bill nye_3
    bill nye_3 Member Posts: 307

    Steve, did you mean Vitola ? or Vitorond? I didn't think my Vitola bi-ferral was a condensing boiler. I can run 90° return water - but it doesn't condense. 87.6% combustion efficiency, but no condense.
  • Steve Eayrs_2
    Steve Eayrs_2 Member Posts: 56
    doesn't condense at all?

    OK its not a condensing boiler like the gas Vitodens, but it must condense some with 90 returns? Isn't that why they have the removable ss bucket on the inside? TO handle the condensate?
    I guess I didn't know they were not condensing. Thanks for correcting me. Wow! 90deg returns and no condensate?

  • Toddid Goldsmith's
    Toddid Goldsmith's Member Posts: 77

  • Steve Eayrs_2
    Steve Eayrs_2 Member Posts: 56
    Love Reillo

    Nothing so special about the parts if you stock them. For a decent price, you can buy every part that could possibly break on the burner, and chances are you will rarely need to remove a part. Comes in a small metal box, about the size of a loaf of bread, and can repair most standard Reillo burners, f-3 thru f-10.

    Sure beats the amount of stuff needed on a truck, to repair most burners.

  • Be serious.

    Riellos are extremely regional in popularity.

    Becketts and Carlins are everywhere, as are parts. Riello? Only in a few areas. Very few. Great burner, but then, so are Carlins and Becketts!
  • Buderus g125B am I about to get ripped off???

    I have a quote for installation of two of these units, with expansion tanks, Watts water feed valves, relief valve, 4 new zone valves, and Honeywell air elimination system; 2 Logomatic controls with outdoor resets; Sidewall venting for both units; 2 tigerloop and Garber Oil filter units; 4 digital programable thermostats, 1 additional zone for unheated area of this large (4000 sq ft)home; removal of old system.
    total job = $25,225. am I getting a bad deal here?
  • mark ransley
    mark ransley Member Posts: 155

    Something to look into, condensing units loose efficency as water temps increase, maybe above 135f, possibly 6% by 180. Some baseboard types and how the house heat was sized mean you could need higher than 140f most of the winter. Do your research. What is boiler temp run at A system 2000 I have heard is worth looking into. Condensing oil is kinda new here, you dont want to be the beta tester that pays, get an extended warranty. You have no gas, it has benefits.
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,537

    verboten to discuss price here.The GB125BE is condensing,the G125BE is not.Big difference

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  • DanN
    DanN Member Posts: 1

    the units quoted are the G125BE.
  • klaus
    klaus Member Posts: 183
    wow! old thread here!

    This one was started in March, and just revived!
    Calls for an update on Buderus. Have installed 6 of the G125 and love that burner! Nicest blue flame you ever saw. No problems with any to date. Sounds like they want a little higher sulfer content in the fuel so no problem here. The GB125 (condensing) is now on the market, and has been for a while. Will be installing our first one of these in a couple weeks.
    I don't think the payback is there on the condensing unless you are doing low temp heating, like radiant floors. Of course there are always the exceptions, like where someone has about twice the amount of baseboard they need, or using a radiant panel that can produce something at lower temps. The point is if the returns are not cool enough it will not condense. The G125 is 89%+, and the GB125 is 94%, when condensing. Difference between the two is an added section on the back of the unit, where it sucks as much heat as possible out of the flue gas. And of course the special concentric stack, wall vent, etc..
This discussion has been closed.