Harmon pellet stove.

mulesriderJanuary 29, 2007

What is your experience? I purchased a Harmon P-38 pellet stove to heat a 1400 sq. ft. log house with an R-30 rated insulated roof. Harmon and the dealer estimated my usage at 1/12 to 2 tons pellets per heating season. I am on my fourth ton and expect to use at least 5.

Harmon provides no customer service. All service comes from the dealer. If you ask a question the dealer doesn't know he calls Harmon. Often times the answer does not match the question.

The temperature probe is very poor. If I shut the stove off for maintenance the probe setting may be different when I turn the stove back on. Even though I do not change the setting. The probe does not allways shut the stove off. Most of the time it goes to a real low fire as if it were in the manual mode.

Harmon says the ash pan will hold ashes from a ton of pellets. Not even close.

Harmon rccomends maintenance after 1 ton of pellets. I find my stove needs maintenance weekly.(which I expected)

Harmon has a way to connect a programable thermpostat to the stove. Your dealer will need to get the information. Harmon wires the thermostat in series with the probe and sets it at a temperature above the probe. All the thermostat does is run the program. You still have to figure out by experiment what temperatuire the probe is set at.

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Wow, tons? like in 2,000 pounds, or 50 40 pound bags, at Walmat via 40 pound bags that would cost approximately $250 a ton, 5 tons (doing the arithmetic) $1,250. What are you paying a ton? How cold is it and what temperature are you heating to? What is the heat loss, R30 in the floor is nice, what about the walls, the ceiling, how many windows and what type? All these contribute to the answer. Now consider that pellets contain about 9,000 BTUs per pound. These and other calculations makes me wonder why one would choose pellets for general (only?) heating. Back to the numbers: at Walmart's price one pays 1.4 cents per KBTU at 100% efficiency, which no one gets. Oil at $2.00 per gallon cost about the same per BTU and modern furnaces will give high efficiency, around 90%. Seasoned hardwood at $200 per cord cost about 1 cent per KBTU and it is at least as efficient as a pellet stove. Looks like hardwood wins, and if one lives in the deep NE I think a FULL cord (hard to find in NJ) cost under $150, why didn't you go for hardwood?

Maybe I'm making "hidden" agenda clear: I'm thinking about replacing a hardwood burning insert with a pellet insert, but the numbers don't look good, and while I understood the pellet stove is much easier to maintain, it appears it may not be. I haven't check in NJ, are you able to buy pellets by the ton for significant savings over the Walmart by the bag cost?

    Bookmark   January 29, 2007 at 8:51PM
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Here are some good facts and figures to help you determine which fuel/stove will work best for you, and how to estimate how much fuel you may use.
1 bag wood pellets (40lbs) = 2.5 gallons oil = 3.75 gallons propane

There is a BTU cost comparison chart on the PFI web page. You must know how much you are paying for each fuel for this to be accurate. http://www.pelletheat.org/3/residential/compareFuel.cfm

In Southern NH a homeowner can expect to use 20-30 Btu's per square foot given standard ceiling height. There is a big range and it can be even larger for certain homes. If your house is a 1750 farmhouse for example I would lean more toward 40 Btu's per square foot. Brand new, sealed up like a zip lock bag, probably closer to the 20. Windows, doors, how often those open, stove location, drafts, insulation, air flow in home, outside weather, wind impact and frequency, ceiling height, wall thickness all play a part. A dealer can only estimate based on the info you give them and their experience. If any of the factors I have mentioned are overlooked or not considered the number will not be accurate. Many people also 'plan' to use a stove one way and end up using it another.
You average about 8,000 Btu's out of a pound of pellets. Some claim more but if you were standing in front of identical stoves burning different fuels you would not be able to tell the difference. I am pretty sure someone can come up with an extreme case, but in my experience 8,000 is a pretty good average.

So here is an example of how to estimate the heat needed in a home: I have a 1000 square foot house (1,000 is small but the numbers are easily related). Built in Southern NH in the seventies, medium insulation, standard ceiling, 1970's windows, 2 teenagers so the doors are always opening and shutting, and I live on a windy hill. Airflow is good, open concept two stories. I put the stove in a corner blowing toward center of house away from front door. I would conservatively put myself in the 30 Btu's. I don't think I will need more because I have a lot of positves. So if I need 30 Btu's for 1,000 square feet I need a stove that can produce at least 30,000 Btu's.

Two examples of how you can estimate your fuel use (using above house):
1. If I am using 30,000 Btu's constantly (not likely but coldest day worst case scenario- again math is relatable) Anyway 30,000 Btu's will equate to a little less than 4 pounds an hour (30,000 Btu's needed divided by 8,000 Btu's per hour/lb = 3.75 pounds)
To see how much I need in a day (remember this is high because I am assuming non-stop 30,000 Btu's) 3.75 lbs./hour times 24 hours = 90 pounds per day used. then times days in month and heating season...
2. Heating five months last year I used 900 gallons of oil. So, since 1 bag = 2.5 gallons, I can guestimate that I will use about 7 tons of pellets if I only use the pellet stove and want the same amount of heat.

To mulesrider. Are you sure you have a P38? It has a max heat output of 43,000 Btu's. It has an ash pan that will hold ash from about 20-25 bags of good quality fuel. It is a manually started stove (no built in ignitor). You can hook a thermostat up to this stove, but it switches from high to where the stove is set only- It will not turn the stove off. The room sensing probe (thermister) is a temperature control device on many of Harman's other stoves. Unlike the thermostat (which is a simple switch) the thermister takes several readings of the room temperature a minute. The control system then determines if fuel feed needs to be increased/decreased or left the same to maintain the desired temperature. The thermister CANNOT be attached to a programmable thermostat as suggested in another thread. The room probe that is used in conjunction with thermister control are very accurate and can be easily tested by your dealer with a tool that plugs into the control board.
Routine maintenance on a Harman stove is generally when your ash pan is full. Including emptying ash pan, clearing out any clinkers in pot, removing thumb screw under burn pot to let down any fines that have collected, and using the scraper tool or a fine paintbrush dust ash off of heat exchangers. If you are finding that you are needing more you may try some different fuel brands. There are differences in "how to" clean different stoves, but the frequency and severity are directly related to pellet quality. Pellets are mostly in the premium grade (less than 1% ash) but there is still a huge difference within that grade.
If you have any questions I will gladly try to help. As with nearly all pellet stoves, Harman does have a dealer based service, so you want to spend some time with your dealer to make sure they are knowledgeable and commited to their product.

    Bookmark   January 31, 2007 at 12:25PM
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Thanks, I made a hard copy for my easy reference. I gave only a brief overlook but can say I agree with your initial BTU content numbers.

One point I felt compelled to make this time is heat isn't "free". I think many people, including happy owners of pellet, corn, wood, and coal, devices think, even claim they are saving a bundle of dollars. I think they are not, and in part because of the high efficiency one gets with natural gas and oil furnaces and with geothermal heat pumps (yes, even with electricity) as compared with the aforementioned.

I have a geothermal myself, and while I have two airtight heating devices, one will handle coal and I've used it, I use them mostly for "fun" and for back-up. There is no doubt that the airtight devices deliver a positive heat gain, as compared with an open fireplace, but to assume efficiencies greater than 70% may give one a false sense of economy.

    Bookmark   January 31, 2007 at 1:04PM
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I agree that people can get swept away with how much they can save. Like somehow if they get a (fill in fuel) stove they will need fewer btu's to keep their house as warm, if not warmer, than they do currently.
Each person has different savings potential. Oil and gas do not cost the same day to day, much less region to region. That is where the fuel calculator can help one person determine if their one scenario will save them. For example, in NH for the past five + years someone who heats primarily with pellet will save over someone heating with propane. Because the cost of propane is so much higher.
As far as efficiencies, there are differences between appliances. Gas wall units are extremely efficient (generally 90-95%), compared to gas stoves (heating not cooking) which have excess air pushed through to give that "wood stove" flame that only have about 60%-70% efficiency. Pellet stoves at ~84-87% efficiency, are much more efficient than a wood burning fireplace which is generally about 10% efficient if you're lucky.
The difficulty with the efficiency ratings in the hearth industry is that they are not regulated or consistently tested. Each manufacturer, on his dime, with a test lab of their choosing, submits a sample stove and install of their choice for testing. Consistency and accuracy are questionable in many cases... Still the averages can work to help compare situations.
Geothermal is a very interesting and efficient heating system. How do you like it? Did you install it?

    Bookmark   January 31, 2007 at 1:59PM
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I believe one of the false assumptions are the efficiency ratings of pellets stoves. They are not actually 84-87% efficient. (I have had several and love them, but those figures are manipulated- I will expand later).

One of my biggest gripes with the industry is the rating of the stoves heating capacity using the btu input, in other words how many pounds of pellets it can burn in an hour multiplied by a generic (who knows what the manufactures use from company to company) btu per pound of pellet equals the btu rating of the stove.

Most pellets stoves heat exchange efficiencies are in 45%-65% neighborhood, the dell point Europa is a notable exception that is into the +90%, and some of the real worst are even less than 45%. So how do the manufactures come up with 84-87% efficiency ? Well it is called an "overall efficiency" rating which includes; combustion efficiency, and some times electrical efficiency.

For instance take a stove with 50% heat exchange efficiency, 99% combustion efficiency, and 99% electrical efficiency you would have an overall efficiency rating 83%. If that same stove was rated at 30,000 btu's you would only realize 15,000 worth of heat when turned all the way up.

So I have owned 4 stoves this season of a quest for the most efficient, and my Harman advance seems to be the best so far, it has an extra heat exchanger on the back wall of the unit and even at full tilt the exhaust pipe is only at about 170 degrees, and the volume of air exiting the exhaust is very low, fair less then the heat exchanger.


It sounds sound like your Harman is having an efficiency issue, I think your dealer led you astray to say 1.5- 2 tons. I live in central PA and I will use about 3 tons this season for a pretty tight 1200 square foot house @ 73 in the living room 68 in the bedrooms. On an average cold day I will use about 50lbs a day. A few nights a it went down to 2 degrees with a 30mph wind and I used about 50lbs in 12 hours through the night, but it held the temp perfectly.

If you have a Harman p38 you do not have a room temp sensor probe, however you do have you do have and exhaust temp probe, and from two of your comments it sound like that may be malfunctioning. 1.-The ash pan may not hold an entire ton worth of ash but it should be close, the fact that you say it is not even close makes me think the stove is over feeding, or not fulling burning the fuel. 2. The amount of fuel you are using for a 1400 square foot house seems really high unless you are trying to heat the house from the basement. What ever your issue is it sounds it is combustion related. Harman dealers are like any other dealer network, there are good ones and bad ones. The fact that the dealer led you to believe that you could heat a 1400 square foot house all season on 1.5 tons leads me to believe either they don't know their product, or they lied. Either way they don't seem like a great dealer.

The p38 is a great stove, in fact at about $1700 new you could not find a better stove at the price point IMO. Sounds like yours need a repair.


I had electric base-board heat, my savings (in reality not theory based on last year) will be about $600, but I am keeping my house at 74 degrees rather than 67 (new born in the house). If I tried to keep my house at 74 with electric I would guess my savings to be closer to $1000, and that is not counting the 20% electric rate increase this year, that would get my potential savings closer to $1200. Further, I have bought my pellets at winter prices ($215 ton), I will pre-buy this year for about $165/ton, putting my total savings over $1300/season.

1 Like    Bookmark   February 12, 2008 at 1:24PM
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Hi Im interested in a harmon P61 pellet stove. I live in Nh and have a 13yr old colonial with open concept. I heat with oil and consume some 825 gallons a season. The question I have is, how many tons of pellets will I consume a season? Im told my consumption of oil will be reduced by half. This would be a savings of some $1800($4.50 a gallon today). Well...If I consume anywhere near 8 tons a season at $250.per ton I would see no savings. Any help would be appreciated!!

    Bookmark   May 30, 2008 at 9:50AM
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If you burn 8 tons of pellets a winter you will hate it. that is alot of work. Not sure but maybe 3-4 ton. even then the cost of the stove installation...do your math properly

    Bookmark   June 19, 2008 at 11:03PM
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This will be our fourth season using our Harman Advance pellet stove. The first year it worked well with the exception of a recall on the feed motor the first week we owned it. Since then our servicing dealer has been out to the house over a dozen times and has replaced the igniter four times, the circuit board three times, the ESP probe once, the thermostat once, sealed the intake air once, adjusted the combustion vacuum twice, and has tried to diagnose several other problems on many occassions.

When we lose power during an outage, the stove quickly fills the house with smoke (so much we cannot breathe) and are forced to open the doors and windows to get fresh air. Our dealer tells us that this is not possible because the stove is a sealed system and cannot release smoke into the room. He claims we have a ventilation problem although I can pull the side panel off of the stove and see directly where the smoke is coming from that was supposed to be sealed from the factory with silicone but looks like they missed the crack. It happens to be in an area that is not easily accessible and looks like the stove would have to be disassembled to be sealed properly.

We also have a problem with the distribution blower cycling on and off rapidly sometimes 30-40 times per minute. The dealer claims he can't ever get the stove to do this when he comes to look at the stove.

These are problems we have had over the last 3 years and we have tried to contact Harman through their website several times and received no response. When we contact our dealer with issues he needs to contact Harman with we never seem to get a clear answer. The dealer has been good about coming out when we call, but cannot seem to correct the problems. We feel like Harman should stand behind their product, but it doesn't appear that they will do so. We do not recommend buying Harman stoves because we feel they are not a company that can be trusted to stand behind their product.

If anyone has had these problems I would like to know. The dealer claims no one else has had the problems like this with any other stove.

    Bookmark   January 29, 2009 at 8:11PM
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I have a Harmon pc-45 stove and have been experimenting with the dip switch settings on the control panel. This all started when I purchased the Optimizer kit 1-00-06801 to run pellets. This has you adjusting dip switches 1,2,7 and 8 to the on position and 3,4,5 and 6 off. The problem is under these settings I go through a lot of pellets and I seem to get a error, "6 blinking light" more often. I seem to know what switches 1 & 2 do but what do the other switches control?

    Bookmark   January 31, 2009 at 3:46PM
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I purchased my Harmon PP38 in 2001, which seemed to work well the first 4 or 5 years. After that the ESP probe would fail every year or every other year. At first the cost of that probe was about $40.00. Now the cost of that probe has jumped to $75.00. The control board has failed twice and now again for the third time. The cost of the board started out at $105.00. The current cost of the board is now $150.00. Between the repeat part failures and the part cost increases, it has become less than cost effecient to operate this Harmon PP38. I can't sell this stove to anyone without first forking over $150 for a circuit that has $25 worth of elctronic parts soldered to it.I am not pleased with the durability of the stove parts and now the new owner of Harmon Stoves has become greedy. The dealership seems to brush off my comments as "that's the way it is, I can't do anytihng about it".

    Bookmark   March 13, 2011 at 11:33AM
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I just cleaned my Harman pellet stove , now it won't turn on at all can someone give me any ideas what to do, or what i did for this to happen? i have been cleaning it for 6 yrs now never had this problem HELP

    Bookmark   January 23, 2015 at 7:07PM
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