Medium-size Wood Stove for Super Insulated House in Vermont

[msnell]

Hi all,

I'm new to the forum. I'll try to be brief in my setup:

I have a super insulated (and super tight) home in northern Vermont (very freaking cold). It was previously quite small (700 sq ft) and I happily heated it with a RAIS Mino II, only using about 1 cord of wood per winter with zero other heat sources. I've since built an addition and more than doubled the overall size of the house, and so the Mino II is no longer up to the job.

I'm currently trying to narrow down my options for a new stove, which must have capability of integrated blower & outside air intake. So far, I seem to be looking at two stoves in particular:

- PE Alderlea T5 LE
- Hearthstone Green Mountain 60 (which happens to be manufactured 15 min away from my house)

I've spent some time looking at reviews online, and on this site. It sounds like its a somewhat common complaint with the Hearthstone stoves that smoke comes out on you when you crack the door open. But otherwise they are well-reviewed from what I've seen.

Are there any other stoves comparable to these two I should be considering?

Thanks for any feedback you all have.

Matt

 

[EatenByLimestone]

Welcome to the forum!

Super insulated houses can be tough to size a woodstove for. Do you know how many btu/hour are needed to keep the house warm at your coldest temps? Did your contractor calculate a manual J?

 

[msnell]

Welcome to the forum!

Super insulated houses can be tough to size a woodstove for. Do you know how many btu/hour are needed to keep the house warm at your coldest temps? Did your contractor calculate a manual J?

I did have a high performance specialist come out and we modeled the house with all the numbers on house size, R-values of walls, roof, windows, solar gain, etc.. and his model calculated I'd need roughly 35,000 BTU/hr to maintain comfort when it's -11 F outside. So that's my starting point.

He also suggested installing a damper in the outside air intake pipe so I can cut off the cold air at night.. though I believe that will depend on the stove. His Napoleon works fine in that scenario of loading firebox before sleep and closing off air intake. I think my RAIS would have choked out the fire if I did that.

But from a real world standpoint, I already lived in the house for 11 years using the RAIS Mino II, and it was a good fit. And ballpark, I'd say that with the new addition the house's heating needs are about double of what it was before.

 

[EatenByLimestone]

That’s more of a need for heat than I expected. Do you have lots of glass? Do you have an open floor plan, or is it pretty blocked off? The main worry is that too much stove will make it so you don’t want to run it over 30F or it’ll cook you out of the building!

 

[begreen]

The Alderlea may be more flexible for milder day burning. It will run fine on a partial load. It's a N/S loader which should be less prone to smoke spillage than a shallow E/W loader.

 

[msnell]

That’s more of a need for heat than I expected. Do you have lots of glass? Do you have an open floor plan, or is it pretty blocked off? The main worry is that too much stove will make it so you don’t want to run it over 30F or it’ll cook you out of the building!

Lots of standard double pane glass in original part of house.

Pre-addition, I would generally only have a fire going for about 3-4 hours out of 24 in December & April. And then closer to 6-7 hours in coldest months. So I’m hoping to do something somewhat similar to that with a bigger stove.

It’s all open on the 1st floor, but then 4 closed bedrooms upstairs. There are some room to room fans and a fan in ceiling near stove to help pull hot air to other parts of house. But I expect the stoves blower will help with that to some degree as well ?

 

[begreen]

Is the addition another floor or a wing addition? A quick sketch of the floor plans may be helpful.

 

[msnell]

Is the addition another floor or a wing addition.? A quick sketch of the floor plans may be helpful.

Stove placement is on top (north) end of 1st floor. 2nd image is the full 2nd floor with central hallway at top of stairs and closed rooms surrounding.

Overall square footage went from around 650 to 1700 after addition, but also addition is better performing with air sealing, thicker walls, triple pane windows, etc.. so I'm guessing its probably roughly double the heating needs as it was before. (though certainly harder to even out the temps throughout the house with more rooms & interior walls. )

 

[begreen]

That should work pretty well for addition, both floors. Not so much for the southern section.

A fan down on the tiled floor area, blowing at low speed toward the stove room will help a bit. The displaced cooler air will be replaced with warmer air.

 

[begreen]

Based on the insulation and window design, I am going to guestimate that the addition will need about 15,000 btus/hr except in the coldest weather. If low and slow would work better, then a pure cat stove like a Woodstock Fireview or Blaze King Ashford is worth considering.

 

[msnell]

That should work pretty well for addition, both floors. Not so much for the southern section.

A fan down on the tiled floor area, blowing at low speed toward the stove room will help a bit. The displaced cooler air will be replaced with warmer air.

that's interesting. I do have a small fan near to the (blue) refrigerator that's blowing downward (away from stove). As well as open floor grates in the two upstairs rooms (in southern section), and room-to-room fans near to those doors-to-hallway. So was hoping the warm air would work its way south, and then get sucked up into upstairs rooms. It wouldn't occur to me to turn the fan around and blow toward the stove though.

For sure its always gonna be a bit colder in that wrapped around southern area. (currently with no stove going at all and running electric heaters in the wood stove room.. it's consistently about 8-9 degrees colder in the coldest part of the house compared to warmest). So its tolerable, but not ideal.

 

[begreen]

It looks like the addition will be easy to heat with the stove.
Cold air is denser and easier to move. That's why pushing cold air down low can be more effective.

 

[begreen]

Could the Rais be used in the original south section as a chill chaser when desired?

 

[msnell]

Based on the insulation and window design, I am going to guestimate that the addition will need about 15,000 btus/hr except in the coldest weather. If low and slow would work better, then a pure cat stove like a Woodstock Fireview or Blaze King Ashford is worth considering.

I've never used a cat stove before. What would be a good 101 resource for reading about that option? Sometimes low and slow is great. Sometimes its -10 outside and nobody has been at the house from 8am-8pm all day, and we just wanna crank the stove as fast as possible and go to bed and hope it puts off as much heat overnight as possible.

So flexibility is important for sure. I never had a problem with the RAIS with sometimes burning very small amounts for longer periods, and other times loading it up as much as it could handle.

 

[msnell]

Could the Rais be used in the original south section as a chill chaser when desired?

Unfortunately not. I didn't do all this math when I should have and hoped the RAIS would be able to handle the whole house. So I removed all the old chimney and installed everything fresh in addition with the RAIS. Its struggled to keep things warm, and we've had to use electric to help the past couple months.

So now looking to swap out the RAIS with a new stove.. and make some minor adjustments to the hearth & furniture to account for a bit more clearance than was planned for.

 

[EbS-P]

You can choose to burn hot and coast or go with a car stove that’s low and slow with constant heat output. I really like my heatpump and secondary tube stove. I don’t need to worry about overheating because when I light the stove I need all the heat it puts out on low.

A blazeking could be an option. So could Woodstock.

Your heating load calculation works out to be 8-9 pounds per hour of wood at -11F. Does that sound about right?? Seems high. 80-90 pounds through the night.

PE Makes a great stove.

If I could do it over again I would get a wood supply that’s more consistent size and BTU content and get a Blaze king.

 

[John Lehet]

That 35,000 number sounds way high if you’ve got a superinsulated house. I lived for 15 years in a 1400 sq foot super insulated house in central Vermont, when winters were colder. I guess my heat demands were more along the lines of 2,000 to 3,000 BTU/hour. I used a soapstone masonry stove to spread the heat of a small fire over 24 hours.

I’m heating a bit less area than you but maybe more volume in an insulation retrofitted 1860s building in Vermont, south of you. VERY far from superinsulated. I weigh my wood. In the coldest weather I burn about 70 pounds of wood in 24 hours, which comes out to an average of under 20,000 BTU/hour by my calculations.

A Woodstock Fireview can dial down low, and also coast along on the heat of a fire with the soapstone mass. I don’t have a Fireview, but a much bigger Woodstock soapstone stove, the Progress Hybrid (the progress would be way too much stove for you). I use it rather like a masonry stove, coasting along on the thermal mass for hours between fires. This morning I made a fire with 15 pounds of wood. I’m going to let the stove sit with coals until about 4 pm, at which point I’ll reload onto coals, light the new fire easily, and build up the coal bed for overnight. You could run a Fireview that way, or run it low on catalyst. The Fireview will run on a low flame/low output much better than my Progress Hybrid.

 

[msnell]

That 35,000 number sounds way high if you’ve got a superinsulated house. I lived for 15 years in a 1400 sq foot super insulated house in central Vermont, when winters were colder. I guess my heat demands were more along the lines of 2,000 to 3,000 BTU/hour. I used a soapstone masonry stove to spread the heat of a small fire over 24 hours.

I’m heating a bit less area than you but maybe more volume in an insulation retrofitted 1860s building in Vermont, south of you. VERY far from superinsulated. I weigh my wood. In the coldest weather I burn about 70 pounds of wood in 24 hours, which comes out to an average of under 20,000 BTU/hour by my calculations.

A Woodstock Fireview can dial down low, and also coast along on the heat of a fire with the soapstone mass. I don’t have a Fireview, but a much bigger Woodstock soapstone stove, the Progress Hybrid (the progress would be way too much stove for you). I use it rather like a masonry stove, coasting along on the thermal mass for hours between fires. This morning I made a fire with 15 pounds of wood. I’m going to let the stove sit with coals until about 4 pm, at which point I’ll reload onto coals, light the new fire easily, and build up the coal bed for overnight. You could run a Fireview that way, or run it low on catalyst. The Fireview will run on a low flame/low output much better than my Progress Hybrid.

I believe the model my consultant was using was possibly also using a lower efficiency stove. But its also tricky math I know with the insulation. Once the entire house & insulation are up to 70+ degrees, the house itself can coast for a long time with no heat at all. I generally don't have the first fire of the winter until October. Prior to that, the sun & warm days are enough gain to coast through the nights with no heat.

So my expectation (and past experience with the tiny RAIS) is starting a new fire once a day, burning for 4-8 hours and then letting it go out. And repeat the following day. 24 hrs/day of fire feels like a different calculation entirely. I've never weighed my wood, but in the past I know I have used on average 1 - 1.25 cords for the entire winter. So I'm expecting closer to 2.5 cords now.

 

[John Lehet]

I used less than a cord of poplar per year in my super insulated house, so you might well need more heat. But my tulikivi was super efficient, and I had passive solar as well.

You probably know, but one principle of a theoretical perfect superinsulated house is that the temperature will be uniform in it absolutely everywhere. Theory vs practice. But I found that was pretty close to true in my house. I had an air exchanger, so that probably was part of even heat distribution. But I sure didn’t need any fan or blower around the wood heater.

With a massive stove, you could probably do what you did before, except make a fire twice a day or more often if it’s really cold. If you can keep coals in the stove it’s nice, because they give off some gentle heat, but also it makes starting the next fire 1000% easier. With that super insulated house, I thought of it as a big thermal flywheel, and I just gave it a push once in a while. Now with the big soapstone stove, I’m doing the same thing, except with more fires than once a day, keeping coals. Just a push on the flywheel now and then. I like it this way.

 

[msnell]

I used less than a cord of poplar per year in my super insulated house, so you might well need more heat. But my tulikivi was super efficient, and I had passive solar as well.

You probably know, but one principle of a theoretical perfect superinsulated house is that the temperature will be uniform in it absolutely everywhere. Theory vs practice. But I found that was pretty close to true in my house. I had an air exchanger, so that probably was part of even heat distribution. But I sure didn’t need any fan or blower around the wood heater.

With a massive stove, you could probably do what you did before, except make a fire twice a day or more often if it’s really cold. If you can keep coals in the stove it’s nice, because they give off some gentle heat, but also it makes starting the next fire 1000% easier. With that super insulated house, I thought of it as a big thermal flywheel, and I just gave it a push once in a while. Now with the big soapstone stove, I’m doing the same thing, except with more fires than once a day, keeping coals. Just a push on the flywheel now and then. I like it this way.

I do have a ductless HRV system in the house (Lunos), but probably due in part to the shape of the house, and the cheaper windows & a door that I now regret, there is some variation in temps from one area of the house to the other once it's really cold outside.

I'm new to looking at catalytic options, and it looks like yours is a hybrid.. I know my wife would be less than thrilled if we can't sometimes see nice roaring flames in the stove, which is central to our living space. With cat-only, would I still be able to see that when on "high" ?

 

[John Lehet]

Though I’m often a bore pushing the Progress Hybrid, you do not want this particular stove. Or probably not. It’s a heat monster. The flames, yes, this stove has the most beautiful set of flame shows ever. I actually almost never burn it on a smolder setting, but always with some flame. I get primary flames off the logs when the stove is not so hot, secondary flames shooting from the top, sometimes “ghost flames” shooting around in the middle of the firebox. And then sometimes a full conflagration with the firebox full of flames like crazy. It might be possible to use it purely as a small masonry stove, but it’s definitely intended to be a serious heater.

The Fireview is not hybrid — a pure cat — but I believe it has a good flame show. Todd can chime in here. I believe he has one. There is a poster on firewoodhoardersclub.com who is always posting videos of the flame show for his Fireview. I think it’s also a nice flame show.

 

[begreen]

I believe the model my consultant was using was possibly also using a lower efficiency stove. But its also tricky math I know with the insulation. Once the entire house & insulation are up to 70+ degrees, the house itself can coast for a long time with no heat at all. I generally don't have the first fire of the winter until October. Prior to that, the sun & warm days are enough gain to coast through the nights with no heat.

So my expectation (and past experience with the tiny RAIS) is starting a new fire once a day, burning for 4-8 hours and then letting it go out. And repeat the following day. 24 hrs/day of fire feels like a different calculation entirely. I've never weighed my wood, but in the past I know I have used on average 1 - 1.25 cords for the entire winter. So I'm expecting closer to 2.5 cords now.

Sounds about right based on your experience. Usually the modeling is done at the expected low temperature. It reads 35,000 BTUS/hr @ 0º or @-10ºF. The Rais Mino II is rated at a nominal output of 17,000 BTUs/hr. At that rate, the Alderlea T5 will get the job done.

 

[msnell]

Sounds about right based on your experience. Usually the modeling is done at the expected low temperature. It reads 35,000 BTUS/hr @ 0º or @-10ºF. The Rais Mino II is rated at a nominal output of 17,000 BTUs/hr. At that rate, the Alderlea T5 will get the job done.

if I'm comparing Alderlea T5 vs. BK Ashford 20.2 my impression is both could work well. The biggest differences being the Ashford would be a bit of learning to use catalytic style, a bit more maintenance, but also more flexibility with longer burn times and ability to burn slower when less heat is needed. Does that sound right?

In my house, in coldest months, would I likely load the Ashford twice a day and keep it going low & slow all the time, vs. burning the Alderlea hotter & faster and only for 6-8 hours a day.

Am I imagining that experience correctly? I haven't compared pricing yet. But are there other major differences I'm missing?

 

[begreen]

The Ashford 20 or 30 would work. They are thermostatically regulated so the larger stove has a similar bottom end output and is not that much hotter. It just burns longer with the larger fuel tank. And the 30 is more convenient to load N/S with 16" splits. There is a learning curve and more maintenance, but it would be a good fit.

The T5 is a very flexible, simple, and forgiving design. It can be run with full, partial loads or just a couple sticks at a time on some hot coals. I have friends up north that are in a super insulated home with a Summit. They are retired and normally run the stove by adding a couple thick splits every four hours or so.

Both are good stoves with a long track record. Either would be a good choice.

 

[begreen]

For comparison, the T5 has an EPA rated output range of 12,518 to 38,177 BTUs. tested with crib wood (doug fir). The Ashford 20.2 has an output of 8,900 to 29,785 BTUs on CW, and the Ashford 30.2 has an output of 11,553 to 27,116 BTUs on CW.