Wood consumption in my PH

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Flamestead

Feeling the Heat
Nov 9, 2011
323
Windsor County, Vermont
I installed my Progress Hybrid in mid January, and managed to burn 4 cords (128-style cords) by the end of the Spring season. This is on par with our wood consumption in the previous stove. Fortunately, even accounting for the mild winter, we were warmer than before. I've been curious about the burn times and wood usage reported by others. Typically the longest I go between re-loads is 7 hours overnight; some days I reload every 3 to 4 hours. I've been concerned that I am burning inefficiently, so I've been playing with the calculator this evening.

With 90 days in the 2012 Feb/March/April calendar, and burning 4 cord of Red Maple that had 21 months of CSS drying time by the start of this period, I realized, at best, 28,000 BTU per hour. (I did burn some in May, too, so my actual hourly BTU rate is lower.)

The EPA stats for the stove says its range is from 12,500 to 73,000 BTU per hour. Woodstock reports a max just above this.

Averages are simplistic - some of days there was no fire, some days there was a lot of fire.

Still, I'd say that 8 cord of Red Maple per full heating season is very comfortably within the expected capacity of this stove. As for burn times, at 28,000 BTU/hr a firebox full of splits should last about 12 hours, but at 65,000 BTU/hr it is closer to 5 hours. I don't spend a lot of effort at maximizing the 2.8 cu ft of firebox, especially when I know I will be around for a reload (I do like to play with fire), so the shorter burn times also seem well within the expected parameters.

Pushing the pencil does make me want to get at my hophornbeam on the other side of the mountain, but as they say, you can't get there from here. My next-best option is to get another year ahead on drying time.
 
Even burning Red Maple It's hard for me to imagine stuffing 4 cord through that stove in 90 days.

What is your typical draft setting?
What size house are you heating?

I have a 2300 sq ft colonial in Northern Mass. and barely burned 2.5 cord all last winter. I know it was mild, but still I'm surprised. My draft setting tends to be fully closed, unless it's really cold and then open up to 1/8 way.
 
The draft is usually set fully closed and then opened back up just a bit. But the draft setting seems related to the burn rate at the time the draft is closed down; if I get it really cruising before setting the draft at its final spot there will be a lot more heat throughout the burn than if I close it down sooner following a reload. On these 20 degree nights this past week we are running the stovetop around 475-500. Tonight I came in just after dark (5-ish), and did about a 70% load (short wood, and not loaded to the gills). Now at 9pm I have a pile of coals the size of a basketball, but the stovetop is down to 350 and I am openning the draft partway to get rid of the coals and make way for more wood. Only 30 degrees outside, but windy and snowing(!).

The house is 2-story 3500 sq ft plus uninsulated walk-out basement. More than a third of that space is behind closed doors most of the winter.

Given the large number of variables (house size, layout, our temperature preferences and work hours, insulation, etc.), I was trying to come at this from a different angle. The BTU math seems to add up to be within the expected range of the stove. When we bought it, Woodstock's first line of questions were aimed at ensuring we had a large enough house. I think many people here are able to run the stove on the lower end of its very wide range of acceptable settings due to better built houses. I think I'm running more in the middle of its range.

(edited emphasis and spelling)
 
OK now I am beginning to see the full picture. 3500 sq ft in Northern Vermont needs lots of BTU's, and your math does agree. I hate to say it, but you have pushed the limits of the Progress. It's hard for any single stove to heat in your situation. Ideally I think you would need two stoves at opposite ends of the house.

I know what you mean about "draft setting seems related to the burn rate at the time the draft is closed down" - that is a very true statement about this stove. But you say you close the draft and then just "tweak" it slightly open, so I guess I am still surprised it burns so quickly. I engage the cat at stovetop temp of 300F. Others go higher and still get longer burn times. I wonder if your draft is exceptionally strong due to an amazing flue settup?
 
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4 cord in 3 months, one 2.8 fire box, thats max.
How is the insulation and draftiness in your house Flamestead ? just wondering. Todd 2
 
The house is 2-story 3500 sq ft plus uninsulated walk-out basement. More than a third of that space is behind closed doors most of the winter.

I assume you're not heating from the basement? Regardless 3500 sq' not counting the basement is a LOT to ask from any stove. I'd say you're doing ok with what you have. Another stove and a lot of insulation would do the trick. :)
 
Any investment made in insulation and sealing the joint is going to bring direct returns in reducing that heating load.
 
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Yes, I'm beginning to realize a second stove would be ideal, and it is on the wishlist. I need someone here to buy a PH and sell me their Fireview.

The draft is good - 32' 6" liner with insulation, in an interior chimney.

I do think the wood could be a better. Next year I'll finally be into the full-length splits (previous stove was 18"), and I've started covering the wood with tin, which seems to be helping.
 
I assume you're not heating from the basement? Regardless 3500 sq' not counting the basement is a LOT to ask from any stove. I'd say you're doing ok with what you have. Another stove and a lot of insulation would do the trick. :)

In the coldest of weather we have to dump some heat from the forced hot air furnace into the basement. Insulation down there would be a big help, but it is a stone foundation and stone floor, and we need to do more on the exterior to reduce the moisture levels before getting much tighter.
 
Any investment made in insulation and sealing the joint is going to bring direct returns in reducing that heating load.

Yes - we've stopped the bedroom door from moving with the wind by replacing windows and adding housewrap before re-siding. Attic still needs more, but I'm wanting to finish any electrical work up there before burying everything. A friend tried to convinve us to add exterior thickness to the walls when we were re-siding, but money was too tight. I don't want to add interior thickness due to historical considerations (20" wide pine wainscoting, etc).

Fortunately we both grew up in cold, drafty houses and don't know any better.

This site brought us into the modern age of cleaner woodburning, and gives a steady stream of ideas for improvements.
 
Sounds like you're on the right track. Heating that many square feet is a challenge any way you slice it. Insulating areas one space at a time will make dramatic improvements. Good decision to get an EPA woodburner. Good luck!
 
I amazed you are able to move that much wood through that stove in one season.
 
With a 32 ft chimney draft may be too good. What flue temps are you running at? Is there a draft damper in the connector?
 
Flamestead you are not alone. My house is not as big and only 207 years old, but probably draftier. New windows, wrapping, and residing still exist only in my dreams as does a roof that doesn't leak. My burn times are more in line with yours than the twelve hour reloads of most. It did me good to hear of someone else in the same boat. I do wonder if I'm just not doing it right when I hear those reload times, although I also have an even stronger suspicion that the heat the stove generates just doesn't hang around in the house as long as it does in more modern houses. But, the house is warm and we're not refilling with 500 gallons of oil every 6 weeks, so I will reload the stove with wood every 5 or 6 hours, thankfully. I don't have any advice to offer, but BrowningBAR with his multiple stoves seems to have the ticket - 92 degrees in an old house indeed!
 
Flamestead you are not alone. My house is not as big and only 207 years old, but probably draftier. New windows, wrapping, and residing still exist only in my dreams as does a roof that doesn't leak. My burn times are more in line with yours than the twelve hour reloads of most. It did me good to hear of someone else in the same boat. I do wonder if I'm just not doing it right when I hear those reload times, although I also have an even stronger suspicion that the heat the stove generates just doesn't hang around in the house as long as it does in more modern houses. But, the house is warm and we're not refilling with 500 gallons of oil every 6 weeks, so I will reload the stove with wood every 5 or 6 hours, thankfully. I don't have any advice to offer, but BrowningBAR with his multiple stoves seems to have the ticket - 92 degrees in an old house indeed!

HollowHill has a point. Adding a second stove to your home will extend the burn times of your Progress by quite a bit. It will probably not increase your wood consumption either, in your case. Let's say you added a Fireview or another Progress elsewhere in the house. The increased burn times you would get by using both stoves would either keep you wood consumption the same or give you a slight increase. Meanwhile you would probably see a jump in your burn cycles by at least 3 hours, if not more while also having more even heat throughout the house.

Heating 3,500 square feet with one stove is challenging. Adding draftiness makes it even worse. Add a second stove and make your life easier.
 
With a 32 ft chimney draft may be too good. What flue temps are you running at? Is there a draft damper in the connector?

The Condor probe never gets above 500. Right now, a couple of hours into a partial load, not fully dampered down, it is sitting at 425. No damper in the pipe. I talked with Woodstock about doing that, and got the sense that it would be an interesting exercise but not one they felt was necessary.

I had the same cat experience as others (new cat was amazing, but sensitivity degraded, and then performance became questionable). I'm on my second cat, courtesy of Woodstock, and suspect it is a different "design" (not as sensitive out of the box as the first cat was). Still too early to share any longevity experience (but I would note, in case someone has missed hearing it yet, that this company provides customer service at a level seldom seen in everyday life).

I think the BTU math shows much more concern for the house than for the stove. I could break out the bathroom scales and moisture meter to get a better sense of my BTU/hour output, but I suspect the answer will still be a house that needs more work.

I am a believer in over-sizing equipment, and I suspect the hybrid functionality extends the range of efficient operation of this stove (hotter but shorter burns and longer but cooler burns are both within the design range of the stove). My sense is that many homes are smaller and better-built than mine, so many PH owners are able to run cooler and longer than I do. The only downside I can see for them is fewer chances to poke at coals and less time handling firewood.
 
I amazed you are able to move that much wood through that stove in one season.

I have the luxury of a sensible, cautious, attentive daughter who re-fires at 3pm while the rest of the household is away at work. But my wood is 18", so I'm wasting 15% of capacity. Also I ran my previous stove hard, opening the damper to get rid of coals so more time could be spent in peak-heat mode. I'm not pushing the PH anywhere near as hard (I don't feel like I'm pushing at all). I suspect I could easily move another 2 cord/season through it while staying well within the design. There was a time in my life where I was impressed with high wood consumption, but these days I'm impressed with spray foam.

Another upside to the second stove is heat while the primary stove is cooled down for maintenance. My steel stove cooled off faster, so it was easier to schedule time for cleaning. I've appreciated learning from your experiences, and the second stove is just a matter of time and money.
 
I would definitely add a pipe damper. It will extend your burn times & lose less heat up the flue. Thats a tall interior chimney . My is outside but well insulated but only 24 feet. And I see a big difference when using the damper.
 
The Condor probe never gets above 500. Right now, a couple of hours into a partial load, not fully dampered down, it is sitting at 425.

Isn't that a very low cat temperature? Is this the temperature directly downstream (exhaust side) of the cat?
 
Isn't that a very low cat temperature? Is this the temperature directly downstream (exhaust side) of the cat?

I assume the condor probe was in the pipe not for cat temp?
 
Flamestead you are not alone. My house is not as big and only 207 years old, but probably draftier. New windows, wrapping, and residing still exist only in my dreams as does a roof that doesn't leak. My burn times are more in line with yours than the twelve hour reloads of most. It did me good to hear of someone else in the same boat. I do wonder if I'm just not doing it right when I hear those reload times, although I also have an even stronger suspicion that the heat the stove generates just doesn't hang around in the house as long as it does in more modern houses. But, the house is warm and we're not refilling with 500 gallons of oil every 6 weeks, so I will reload the stove with wood every 5 or 6 hours, thankfully. I don't have any advice to offer, but BrowningBAR with his multiple stoves seems to have the ticket - 92 degrees in an old house indeed!


HollowHill, we are still chipping away at improvements, doing a lot of the work ourselves. In my book, the roof and foundation are the imperative points. Then stop the drafts - spray foam is a modern material, incongruous with the historical building materials, but it is a non-damaging bandaid that can easily be undone later by you or some other restorer. All my new windows are sealed in place with foam, so it isn't just for temporary patches. In hindsight, during the years before we could afford the windows I should have filled the pockets for the sash weights with foam. I don't think the to-do list ever ends. Now our slate roof needs work, and someone had the gall to suggest that our chimneys need to be rebuilt from the roof line up within 10 years. Sigh.

Here's where we are today (PH is running mid-load at 500 stovetop on right hand chimney, can't see the liner cap from here, no smoke (still seems like voodoo)). The house work is a multi-year plan. We've got a color difference on the scaffolding side due to some siding going on last fall, and then more this summer.
DSC02466sm.JPG
 
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Isn't that a very low cat temperature? Is this the temperature directly downstream (exhaust side) of the cat?

Probe is in single-wall pipe. Horizontal flue exit, 18" over to the T, probe just above the T.

I'd like a cat probe (Internet accessible, please), but am doing OK with stovetop and flue temps.
 
I'd say you're dfoing fantastic to heat 3,500 drafty square feet with one stove. I see no need for a pipe damper right now. It doesn't sound like you really want a slower burn since you need the heat. The reason your burn times are shorter than most of us with the same draft setting is probably because you have some crazy draft with that tall chimney. If you did add a stove, then a pipe damper would be a great idea because it would allow you to get the long burn times the rest of us do.

Speaking of long burn times with the PH: I'm currently 15.5 hours into my load from yesterday. Stovetop at 300 and still a log shape of coals in the back of the stove. This was a "full" load but with 16" splits. So, really only 72% of capacity. Long burn times are definitely possible, but not in your situation because you need so much heat. I really think you're doing great!
 
I suspect I could easily move another 2 cord/season through it while staying well within the design.
Wow. That is amazing.

There was a time in my life where I was impressed with high wood consumption, but these days I'm impressed with spray foam.
I can completely relate.

Another upside to the second stove is heat while the primary stove is cooled down for maintenance. My steel stove cooled off faster, so it was easier to schedule time for cleaning. I've appreciated learning from your experiences, and the second stove is just a matter of time and money.
Again, I can relate. Doing three installs three years in a row was incredibly tough to budget. I am very glad that part of the process is over. If you can budget it out, I would do another stove the size of the Progress (whether it is a Progress or not is up to you). But, if you did two cat stoves of that size, I really think you would end up getting 12+ hour burns with more even heat.
 
I see no need for a pipe damper right now. It doesn't sound like you really want a slower burn since you need the heat.

On this, I thought that you could actually get more heat from burning with a proper draft speed since the hot flue gases have more time in the stove to be exchanged to the stove. So a higher stove temp could be achieved and held with lower wood consumption. That high draft speed may be sucking the heat right away from the stove.

Sounds like the PH is the proper type of heater for such a large heat demand. Those brick chimneys look gigantic.
 
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