Advice on picking a stove for a new tight home

[Ashful]

my head is spinning a bit on the btu demand. I understand the concept but am not sure how I would figure out my actually usage. I like the mathematical approach it should be pretty fool proof, however there are so many variables with wood moisture,species,ect im leaning towards just getting a large non cat stove and hopefully dialing in how much to load it. On thing that caught my attention from poindexter was hooking the OAK directly to the stove so you have sealed combustion just like any direct vented appliance. That makes the most sense to me in my situation but seems to be a major no no around here from what I had read. From what I have seen all manufacturers purposely use an indirect connection I assume to prevent the combustion from exiting the intake in a worst case scenario?

You're likely a candidate to run the way I do, so at the risk of boring everyone who's been on this forum for more than a month, here's my method. I'm sure there are many others running the same way:

1. Buy a big stove (or in my case... two) with very predictable burn times.
2. Decide what you want your reload schedule to be, whether it be 1x, 2x, or 3x per day. The stove should be your slave, not the other way around.
3. Find the air control settings that give you burn time to perfectly match that reload schedule, meaning you're down to minimum coals required for a new load to self-light on that pre-determined reload schedule.
4. Leave all of your central heating thermostats, programmable or otherwise, on the settings that make you comfortable. This is what will keep you happy and warm when your reload schedule doesn't perfectly match your home's complete heating needs.
5. Enjoy the savings. At $5/gallon of oil, you can expect to save over $1000 in oil per cord of quality hardwood burned. Convert to your fuel of choice.

A couple of notes:

1. The most predictable burn times, especially if you're going for those 1x or 2x per day reloads, are going to come from a cat stove, NOT a non-cat. I can hit perfect 24 hour reloads with my BK Ashford 30's, that I'm quite certain no one could ever achieve with a non-cat.

1a. This is where bholler is going to respond that 24 hour reloads won't do much to heat your home, and in the dead of winter, he's right. I step one of my stoves up to 12-hour reloads for the 3-4 coldest months, and will even sometimes step up to 3x per day if it's single-digit weather. But then I also have the luxury of stepping it back to 24-hour reloads for a month or two, either side of that, and I've marked my air control for all three scenarios.​

2. A cord of most hardwoods is worth much more than $1k in oil, even more than $1500 at today's prices. However, stoves don't have programmable thermostats, meaning your BTU usage will likely be higher overnight and while away at work, than it would be on oil alone.

 

[EbS-P]

Well sort of they are designed to burn continuously under worst case scenario conditions. Wood stoves also don't put out that max BTU for very long either

100k btu per hour would be about 20 pounds of wood per hour by my math.

my head is spinning a bit on the btu demand. I understand the concept but am not sure how I would figure out my actually usage. I like the mathematical approach it should be pretty fool proof, however there are so many variables with wood moisture,species,ect im leaning towards just getting a large non cat stove and hopefully dialing in how much to load it. On thing that caught my attention from poindexter was hooking the OAK directly to the stove so you have sealed combustion just like any direct vented appliance. That makes the most sense to me in my situation but seems to be a major no no around here from what I had read. From what I have seen all manufacturers purposely use an indirect connection I assume to prevent the combustion from exiting the intake in a worst case scenario?

I Could be wrong but most stoves with an OAK it is sealed to the stove. My insert has a knockout in the jacket that doesn’t seal to the stove intake and I think it’s not the best design but I get why they do it in an insert. The requirements that the OAK terminate at the same elevation or lower prevents flue gasses exiting the intake.

Where are you reading that the OAK are not a good decision?

Details matter for determining an accurate heating load. Can you look up how much electric/gas/oil you used last winter? You can always do a manual J calculation.

At the end of the day the I don’t think an accurate calculation is as important as a good installation. The perfect stove won’t work if it can’t draft. The OP still hasn’t confirmed the flue height from first floor. Whether or not a liner is planned or not. How high the thimble is. Or whether wood will be 20% or less.

 

[stoveliker]

There have been many debates about OAKs, and begreen posted a link to an old thread lately somewhere with a lively discussion.

The point is that an OAK can be dangerous IF there is a chance for it to act as a chimney, i.e. for exhaust gases to go out of it. Obviously OAK material is not made to contain hot gases.
That is why the requirement that bholler mentioned is there: make sure the air going from outside to stove has to run up through the OAK.

Given tightness and air handling systems, I certainly would do the OAK. You could likely have smoke smell issues if you don't.

A UL listed stove with an OAK has been put through the wringer to see what can go wrong. Being listed means that (if properly installed), it's safe. I woud not doubt that regardless of the stories "out there".

 

[Poindexter]

@Codylbz413 , as above the risk with an OAK piped directly to the intake on your stove is that it might, in some circumstances, act as the chimney to your stove while the actual chimney pipe serves as the air intake for the firebox. The main thing you can do to prevent that is to have the inlet for the OAK on the outside wall as low as possible and definitely below the floor of the firebox of your wood burner. I do not know the prevailing regulations in Massachusetts, and local airflow within 0-50 feet of your building does matter.

If you can't do a hard piped OAK, internet search on the 'Whisper product," whisper 800, whisper 1000, just keep throwing different numbers after whisper until you start getting hits. That is the one to get up here, though I don't own one and have no affiliation.

I do agree with "@various" this doesn't sound like a place to use a non cat stove. You have some reading/research to do on this subject. Having used both, I would not even look at non cats and be shopping among catalytic stoves. When you are looking at year on year energy consumption, it comes down not just to BTUs in the envelope, but also how smoothly they are delivered.

Whether or not you have measured it, your insulation envelope lose some degrees per hour to the outside ambient air, and it is a curve. If you are running AC, you lose more degrees per hour the hotter it is outdoors. If you are heating, you are going to lose more degrees per hour the colder it is outdoors. The curve on my 1980 build crosses an exponential knee around -30dF and my heat loss in degrees per hour starts going up really fast as the outside temperature drops slowly. In a more modern build I would hope for that slow/fast crossover to be at an even colder temperature.

With a recent, like 2015 or or later build, of 3600 sqft in MA that hit a reasonable target on an actual air door test, something like 100k BTU/hr for the main heat source for peak output is in the probably reasonable range. You can supplement the dog out of that primary heat source without your insurance agent raising an eyebrow. If your chimney is a pro install, the insurance agent is worried about freezing pipes and not worried about your wood burner.

Yes my boiler at 100/120k BTU/hr hits max duty cycle around -35dF in 2400sqft, but I am in a 1980 build. I lived in Schenectady for about 10 years before the turn of the century. At the time -20dF was pretty darn cold, and we got to -50dF once with wind chill included in the complaining. In Fairbanks we don't talk about windchill at all until we get to the areas where exposed flesh freezes instantly, sort of -75dF and lower, those forecasts make the front page of the newspaper.

 

[Codylbz413]

Thanks for all the advice everyone. My take away from everything is I should probably focus on getting an OAK hooked up and make up air to make sure the house is balanced( should be done,even without a wood stove). I’ll run this stove this winter unless I find a deal on a stove I can’t pass up.
ashful you summed up my approach perfectly. Burning wood is more of a fuel bill supplement/hobby as well as a back up heat source, I feel like the little stove I have now could just about keep up to my desired temperature I had my thermostat to with a short burn time because it was cranked.
So hopefully I’ll do a little better with a more controllable burn with the OAK and I’ll keep and eye on my propane use and. What not and maybe upgrade Stove at a later date.

 

[bholler]

Thanks for all the advice everyone. My take away from everything is I should probably focus on getting an OAK hooked up and make up air to make sure the house is balanced( should be done,even without a wood stove). I’ll run this stove this winter unless I find a deal on a stove I can’t pass up.
ashful you summed up my approach perfectly. Burning wood is more of a fuel bill supplement/hobby as well as a back up heat source, I feel like the little stove I have now could just about keep up to my desired temperature I had my thermostat to with a short burn time because it was cranked.
So hopefully I’ll do a little better with a more controllable burn with the OAK and I’ll keep and eye on my propane use and. What not and maybe upgrade Stove at a later date.

You probably also have excessive draft with a chimney that tall. A pipe damper could bring things under control

 

[Codylbz413]

You probably also have excessive draft with a chimney that tall. A pipe damper could bring things under control

Yes I do have one already, I never messed with it. I will keep that in mind!

 

[stoveliker]

If you have never messed with it, I wonder how much of your heat goes up the flue now.
I.e. you might get more heat out of the current stove if you use the damper. I'm not saying a US Stove is going to be a very good one (and its longevity won't be as good as many others), but if it can't heat your home, AND you have a lot of draft, that could be a first thing to work on. Get the draft under control and see what the stove does then.

Do you have a flue probe (thermometer that sticks through the stove pipe into the flue gases)? It'll tell you whether you are burning somewhat efficiently (i.e. keeping the flue temps low for efficiency, and, as important, high enough to avoid creosote condensation).

Note that BK will refrain from suggesting a key damper in your flue (they are bound by some legal issues). However, I note that even one damper may not be enough. @kennyp2339 has two I believe.

This is all apart from the good strategy to hook up an OAK.

 

[Codylbz413]

If you have never messed with it, I wonder how much of your heat goes up the flue now.
I.e. you might get more heat out of the current stove if you use the damper. I'm not saying a US Stove is going to be a very good one (and its longevity won't be as good as many others), but if it can't heat your home, AND you have a lot of draft, that could be a first thing to work on. Get the draft under control and see what the stove does then.

Do you have a flue probe (thermometer that sticks through the stove pipe into the flue gases)? It'll tell you whether you are burning somewhat efficiently (i.e. keeping the flue temps low for efficiency, and, as important, high enough to avoid creosote condensation).

Note that BK will refrain from suggesting a key damper in your flue (they are bound by some legal issues). However, I note that even one damper may not be enough. @kennyp2339 has two I believe.

This is all apart from the good strategy to hook up an OAK.

I only have one of those magnetic thermometers on the stove pipe right now, but I will have to get a probe type I’m sure that’s a lot more accurate.

 

[bholler]

I only have one of those magnetic thermometers on the stove pipe right now, but I will have to get a probe type I’m sure that’s a lot more accurate.

Magnetic thermometers are perfectly fine on single wall pipe

 

[Ashful]

Magnetic thermometers are perfectly fine on single wall pipe

I remember a few past members running comparison tests with both magnetic and probe thermometers on the same single-wall pipe. I seem to remember a pretty consistent 2:1 ratio between them, with magnetic reading roughly half of probe, over a wide range of temperatures at (assumed) steady-state condition.

I run a magnetic thermo on single wall on one of my Ashford 30's, and a probe on double wall on the other. I run them roughly under this assumed (roughly) 2:1 ratio.