A conversation with Andy Boutin about Pellergy’s oil-to-pellet furnace retrofit

My guest for this week’s Innovators podcast is Andy Boutin. I first heard from Andy when he made this comment on my December 2007 entry about biomass heating. Then his name came up again in my conversation with Jock Gill. Clearly I had to interview Andy too.

His method of retrofitting an oil furnace with an alternative pellet combustion system will be of special interest to a certain number of folks in the northeastern United States. But the pragmatic systems engineering approach that he took is a model for a lot of other innovations that can, and will, move us forward in the years to come. Yankee ingenuity is about to make a major comeback, and not a moment too soon.

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18 thoughts on “A conversation with Andy Boutin about Pellergy’s oil-to-pellet furnace retrofit

  1. Anyone have any ideas of when or if bulk delivery will be coming to the northern part of Vermont???

  2. Andy lives in Montpelier and gets bulk delivery there, but we discussed this and he feels it may be a couple of years before it’s more widely available.

  3. Domestic steam boilers are the most INEFFICIENT heating systems available. Steam heat, by it’s intrinsic nature, has to boil water. In the process MUCH heat has to go up the chimney… and this waste heat goes on before ANY heat gets delivered to the radiators. Once the water boils, then the steam goes thru the pipes to the radiators, and finally gets delivered as heat when steam condenses back to water in the radiators. Heating systems efficiency depends on 4 things:
    Start-up efficiency <– steam very bad!
    Combustion efficiency <– system dependent
    Heat exchanger efficiency <– steam bad!
    Standby efficiency <– steam _very_ bad!
    Andy is only addressing one of the above. For efficiency, _all_ 4 factors have to be addressed. Respectfully, the system Andy ended up with remains _very_ inefficient and wasteful of whatever fuel fired with.

    When I moved into our home ~30 years ago I faced same situation. I finally concluded our old steam system had to be replaced; I switched to a hot water system. True this did take initial capital cost, but I ended up w/ a heating system that is vastly more efficient & has now paid for itself _many_ times over. Andy is not really addressing “environmental” issues at hand – he simply converted to a different fuel.

  4. Steam heat clearly has its issues, but making it with renewable fuel is an improvement over making it with fossil fuel. The bigger picture is that most Pellergy installations will NOT be in stream systems. Nor in hot air systems. In fact, many Pellergy systems will be in NEW triple pass boilers. Some Pellergy installations will also use solar hot water systems as components of the over all system to reduce the amount of biomass fuel required.

    Ultimately, Pellergy systems will be used in conjunction with Micro-CHP solutions.

  5. Steam heat is such a “looser” _no_ fuel can reasonably justify it’s continued use in a “domestic” heating system. Originally it served a ‘need’ when electricity was not available to “move” the heat. (Ie, steam can be fired w/ wood or coal; no electric needed.)

    Steam could be used in a co-gen system, but would still suffer inherent systemic losses.

    Biomass may be used as fuel, w/ some added manual effort & ‘risk’ wrt reliability (on account of necessary maintenance issues.)

    Overall, IMHO, one is better served using constant circulation hot air or hot water systems, which when “gravity” circulated, also don’t require electricity or complex control systems. Constant circulation in radiant floor applications, also yields a “physiological” fuel savings as “comfort” levels can be attained at lower absolute Temperature as well as lower delta T. If one focuses on these advantages, fuel so much reduced, savings really maximized.

    Interestingly, gravity circulated hot air and hot water systems (again, no electric required) used to be routinely available, remain thermodynamically most efficient, and inherently as reliable as gravity.

    To _best_ utilize above however, combustion need be _intermittently_ fired – ie, not so suitable to the like of pellets. Choice is “yours”… I choose nat-gas. My fuel cost in Central NJ, for 2k sq ft 1915 house was ~$250 /winter when I installed ~25 yrs ago, now still less than $500, and I still have _not_ upgraded 17 WW-I single pane windows.

    Having said all above, overall I recommend super insulation… where no central heat system would be required. geo-thermal is also an option, tho capital $$$. :-)

  6. Well, I guess I need to weigh in here….

    First of all, how could one defend a 100-year old steam heating system as an efficient, up-to-date heating system? I can’t, but here are the facts leading up to my decision to convert from oil to wood pellets.

    My primary objective was to find a way to heat my entire house with a renewable heating source that would also reduce my carbon footprint. I was burning 1200 gallons of oil a year providing heat and hot water in my circa 1910 house. The house’s original coal boiler was disconnected in 1994 and a new (at the time) Peerless JO Series boiler was installed into the existing steam heating system.

    In investigating my options I had a company come in and give me an estimate to convert my steam heat to hydronic (circulated hot water). The quote was just over $35,000 to replace the boiler with a high efficiency boiler and to run copper and/or PEX to the radiators, establish zones, perform the full installation, etc. The results were not guaranteed, but there was an estimated savings of 3-400 gallons of oil per year.

    Investing $5,000 in a PB-3550 wood pellet burner system saves me burning 1200 gallons of oil per year.

    Recognizing that I’m still filling a leaking bucket with a different media I am now focusing on weatherization: New storm windows throughout the entire house, and this year high density foam insulation in the attic, possibly in the basement if the budget can bear it. These are being paid for with the previous year’s savings in not burning oil (although with oil prices where they ended up this year, that savings is less than $400 for the 08-09 season…as opposed to $1,100 last year).

    When firing on oil the existing system achieved 81% efficiency. When converted to Wood Pellets I max out at 78% efficiency and average 76%. Admittedly, this is not great, but as Jock pointed out in his post: With one of the newer triple pass boilers, I could be right back up into the lower to mid eighties even with Steam Heat; the cost would be an additional $3-4K in the new boiler cost and I could use my existing PB-3550 wood pellet burner. Where is this money best spent, in insulation or a new boiler…when the one I have works well, and the insulation I have is horrid?

    I happen to like living with steam heat as well. I have removed and redone the historic radiators, balanced the single pipe steam system to give nice even heat, and actually enjoy the hot cast iron radiators throughout the house. Don’t get me wrong, I love radiant, but that is not an option in an old house such as this (and most others of this era) where there is tar paper under the hardwood flooring.

    Converting to hydronic at a cost of over $35K for 5-6% efficiency still doesn’t seem to make sense.

    I still feel that my best option was the smaller capital investment, keeping the existing steam heating system in tact (both functionally and aesthetically) and firing with wood pellets. After added insulation I will focus on a more efficient boiler and continue to heat with steam.

    Is this the best option for everyone? No. Is it the only option? No. And, if cost was not a variable, could you do better from a total environmental perspective? Yes.

    Integrate a Pellergy burner with a new high efficiency triple pass boiler, add solar panels and active electric backup, remove old inefficient insulation and replace with high density foam. These are all great options and may be best for some, but not all.

    One of my primary objectives with Pellergy is to provide a system that gives multiple options to fit different levels of budgetary capability. We’re going to keep developing burner systems to accommodate both larger and smaller systems. We’re committed to building these here in the USA and to help get as many people heating with renewable wood pellets as we can. In the mean time, let’s all continue to advocate for, and implement systems with better efficiency and less energy usage. the combination of these two is the only path forward that is sustainable.

    Thanks for the comments.


  7. Andy – First… thx for your reply.

    A thoroughly lucid & _excellent_ follow up.
    I’m startled at a $35,000 conversion cost! I can’t argue with your romance for steam, tho I’m happier w/ better placed radiators I was then able to install in my old home, so literally increasing usable floor area.

    I do “argue” with efficiency numbers cited; generally such numbers only wrt combustion efficiency which must be multiplied by the other (overall) systemic losses. When one does so, steam looses much, as I described (only measuring steady-state combustion is not a proper measure of system efficiency).

    Nonetheless, with gross installation costs such as you quoted, your _fiscal_ argument certainly was sound.

    Again, I converted ~25 yrs ago. I removed the old system myself, and it only cost me $3,000 to have the new HW system installed, and I ended up w/ fuel costs ~16% of steam (yes, really… _only_ ~16% of previous).

    PS: Zones not needed; adtl cost/complexity & lessened reliability, not worth it. Way over-hyped. I used 37 Watt Grundfos pump, so my electric costs minimized too. In an old home zones also add piping costs. You see, I strove for simplicity & efficiency. Overall, I think I made a good fiscal, and environmental decision. Nonetheless again, your whole analysis essentially sound too.

    Rgds & good luck in your endeavors, Jeremy

  8. Dear Friends,

    We would like to draw your attention towards the same work we have done in INDIA. We retrofitted more than 30 nos Steam Boiler ranging 3 TPH to 8 TPH in the period of 2 years. We have converted 18 nos. steam boiler OIL to Biomass Briquette ( large pellets) with in the company like PEPSI and COKE. Not only we enhanced boiler capacity but we equipped boiler with most efficient system. We are getting 85 % Thermal efficiency with our system. Payback period for the conversion was less than 90 days.

    Regards & Good Luck

    for Mago Thermal Group,

    Naveen Goswami



    Since the interview there have been a few developments in bulk pellet delivery into Northern and Central Vermont. Looks like there will be no fewer than three companies that will have pellets from either Maine, New Hampshire or Colorado (via rail into Barre, VT).

    Great development and sooner than anticipated!

    In Maine, Heutz Premium Pellets is now delivering bulk pellets in and around Lewiston via brand new pneumatic delivery truck.

    More will be certain to follow.


  10. Dear All

    Thanks for your valuable comments,

    Retrofitting og oil firing system to pellets not only save cost, but reduces corbon emission also.

    Kindly help me, in case somebody wnats to convert their oil firing system to Biomass, I ready to help them out.

    Lets save earth.

    For further detail you may contact me.


    Naveen Goswami
    email : magothermal@engineer.com

  11. Hi just thought i would tell you something.. This is twice now i’ve landed on your blog in the last 2 days looking for completely unrelated things. Spooky or what? If you wantto exchange the links with us please let me know.

  12. Interestingly, gravity circulated hot air and hot water systems (again, no electric required) used to be routinely available, remain thermodynamically most efficient, and inherently as reliable as gravity.

  13. @Manize:
    You are *completely correct*… “gravity circulated hot air & hot water systems (no electric required) used to be routinely available, remain thermodynamically most efficient, and inherently as reliable as gravity.” [btw, fwiw: notwithstanding I do *not* recommend steam as it’s inefficient, does not need electricity either]
    I would only highlight, “thermodynamically most efficient” wrt heat exchanger efficiency [both combustion heat exchanger & delivery heat exchangers]. However, gravity systems in and of themselves do not address combustion efficiency. To have the best overall system one must burn fuel at the best /highest efficiency too. Indeed, some systems enjoy synergy among their combustion systems, control mechanisms, and heat exchanger efficiencies. Bottom line, low circulating “fluid” temperatures are simply most thermodynamically efficient.

  14. Oh… I forgot: When one does *not* use electricity, ie, if one uses “gravity” to circulate the working fluids, you ADD to overall *system* efficiency, since the thermodynamic energy electricity represents would be at ~4x the cost of the same energy delivered thermally (ie, gravity uses thermal energy, rather than electricity). Finally, IF you can use naturally aspirated combustion systems (eg, pulse combustion), you save (ie, do not use!) even more electricity!
    See, what most people do not “remember” is that it’s 8systemic* efficiency one is after… not simply use of bio-mass, or gravity, or whatever. To get best overall performance all component parts of a system need to be as good as possible… not just one element.

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