Truth be told I don’t know what the most efficient oil fired water heater is.
I know in my local area, with the distributors I work with, the Bock line of oil fired water heater tanks are our preferred oil fired tank and I believe they are the most inefficient but not 100% sure. I’d love to see a case study or comparison chart about this. (Maybe I will.)
The Bock line does have a Superior Heat Exchanging Process & Venting, which is why I think they are the most efficient
Simply put, Bock has a Superior tank venting & heat exchange process design all oil fired Bock tanks have something called Turboflue. Which is basically, metal fins that go throughout the vent column. The metal fins captures more heat from the hot exhaust gases before they are released from the top of the tank into the chimney. The metal fins capture more heat transfers it into the tank, which is a more efficient heat exchanging process that other competitors. Bock’s website gets a bit more technical about their patented Turboflue® Heat Exchanger here.
Here’s a look at a Bock with a portion cut away so you can see the a section of the tank & venting from the inside.
I personally took these pics.



Copying Bock’s design: Although the Turboflue is patented by Bock, just about all the other manufactures have added some kind of fins or baffling systems within their venting systems now to capture more heat and promote better heat exchange over previous generations.
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Jay Sullivan
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