Efficiency of a Harman SF 360

I am looking to purchase a Harman SF 360 as my main source of heat for my home! I am curious what the efficiency of the boiler is when burning wood and when I am burning coal. I can't find this info on any website that sells this product! Thanks for any info you can pass my way

Jon

Hi Jon Boy, welcome to the forum... I'll try to answer your question, the reason that very few coal or wood stoves/boilers have effeciency numbers given for them is that there are just too many variables to account for in the fuel and installation, chimney and heat load on the boiler or stove.

Wood can vary greatly from species to species, I think Hickory and Red Oak are the highest [and heaviest] BTU content wood available.. But moisture content varies greatly too. If you have truely dry wood, that has been cut and split and stored under cover or indoors for two or more years, then you have very little moisture to burn off before the wood is burning fully for heat output. If the wood is wet, it can use over half it's available heat content just burning off moisture.

Coal also varies a lot, Good deep-mined coal has low ash content, and burns with very little if any unburnt coal in the ashes. A lot of strip-mined coal has higher ash content, over 20% sometimes, and often has a lot of unburnt 'bone' or 'slate' in the ashes.. I've had coal that I tossed out 25% of the coal as ash and unburnt coal/slate.

The qualtiy and effeciency of the chimney that the stove or boiler is hooked to has a big effect on how well it burns and effecient it is, and if a barometric damper is used or not will make a huge difference too.

So with all the variables if a manufacturer was to offer a effeciency rating, it would either be fictious, or a very wide range number like 35%-55%, or there would be a very strict list of conditions under which the test to determine the effeciency took place, and a serious disclaimer about your expectations..

Oil and gas heating units are pretty easy to rate for effeciency because of the consistency of the installs, the consistancy of the fuel and how easy it is to be able to repeat the conditions of the test..

If you want to read a very thorough effeciency test of a coal boiler, go to the Stoker forum on this site, and open the 'Axeman-Anderson Library' and read the 'Bureau of Mines Report' on the AA boiler, you will see what I mean above.

Now for some good news, the Harman hand load boilers are very well built and I've seen them burning, they look like a good product.. Are you sure you want a hand load boiler? Are you going to burn both wood and coal?? or just coal?? do you have a good source for Anthracite coal or are you planning on burning Bituminous coal?? Do you have a good tall chimney available or are you going to install one??

Hope this helps, let us know more, we'll be glad to assist if able to.

Greg L

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Hey Jon, I have the SF260, ten years now. One of the best investments I ever made. Besides cleaning the chimney & the ash pan, it's never missed a beat. I haven't had the best of luck with coal, one of the reasons I found this site. Wood, however, I've been doing since I could pick a piece up, and I'm 56. We heat a 3500 sf 2 story, with 3 zones on thermostats. The Harmans plumbed into the oil boiler, when the Harman temp gets to 140, a circulator comes on, the furnace won't Free hot water too - All we've ever needed - All the mess is in the basement instead of the stove in the l.r. we used to have. I don't know about eff. ratings, never really cared, not like I'm going to change units [at 2000.00] to get one a little better. Here in NW Connecticut, I use about 6 or 7 cord from late Sept. to Late Mar./ early Apr. I'm going to get into some coal questions when I have some more time. We do like that Harman though -

I really appreciate all of your input. It looks like the Harman sf 360 is the one for me. I was very glad to hear about the bituminus vs. the anthracite thing. I will have to check and see what the guy down the road sells. What would you say about the triple fuel (wood,coal,oil) Harman sf 360. The only reason I like the idea of having oil thrown into the mix is that is gives me some freedom if I want to go visit family in PA (I live in Northern Maine) over the winter! I look forward to your imput!!! This site is the best!!!

What is your current heat source?? An oil fired boiler?? I'd just keep it and use the Harman in series with the current boiler, and it will pick up the load if the Harman is shut down.

Greg L

One thing I forgot Jon, when we plumbed the two units together, we put bypasses on all three zones. If the power goes out, you can open these a little & hot water will circulate through the house. Sure beats freezing. With the auto draft off [no power] you just run the fire as you would in a regular stove.

Hi! Sorry for my english: i'm from quebec, mont st-hilaire. I'm looking for a Harman boiler for heating my indoor pool. I Want to heat the water and the floor of the pool. What is the difference between the 260 and the 360? What is the difference between them in the consommation of number of wood cord?
Thank you everybody
JF