Long burns 20+ hours, how is this possible?

[Fargo]

TLDR: I'm getting 24 hour burns and my mind is blown at how efficient this stove is running.

So I had my Ashford 30.2 installed at the end of Dec and I've gotten about 6 weeks of burning on it now and its been an interesting journey. Initially, my wood was a bit damp and I ran the fan on high with the thermostat a little more than half way open over night. This would give me around an 8 hour to 10 hour burn time. So I filled it 2-3 times a day. This worked great when it was -20* F+/-. But as outside temps got above 0* it started getting too hot in my house. Around that same time I also acquired a cord of drier wood to burn. So that my have contributed to the higher heat levels as well as the higher outside temps.

So in an effort to bring my house down to a more reasonable temp, I started only burning at night and let it cool off during the day. But I missed having the hot coals to start a fire. So I decided to try turning the thermostat down further to get longer burns. That didn't really change things a whole lot. But then at some point, I turned off the fan. Wow what a difference. The fan must pull off enough heat to keep the thermostat open further. Because the last couple days, since turning off the stove fan, I have had the thermostat down to just at the start of the white marking and I get really long slow burns. Yesterdays burn was close to 24 hours. As far as I could tell my cat never fell below the "Active Zone" that whole time. So for almost 24 hours I had a low slow fire going within the Active zone.

My current load was filled around 11pm last night and right now, after 12 hours of burning at about 11;20 AM, my stove pipe temps are around 215* and the needle on the cat probe is at about the 12 o'clock position. (Or right in line with the stove pipe. So about halfway around the dial.) With lots of unburned wood still sitting in the firebox. So it looks like I will get about another 24 hour burn.

I'm new to wood stoves, but this seems crazy good to me. From reading forum reviews, I was fully expecting to be able to achieve 12 hour burns, but never did I think I would be able to get by loading once a day. I keep looking to see if I'm missing something, but everything seems to be good. Granted our outside temps are in 20*-35* range, so not much heat is needed. But needless to say I am very pleased with how this stove is working.

For reference the stove is in the basement and using the house fan to circulate the air, it puts out sufficient heat to heat both basement and upstairs during these more mild temps. Additional note, I have an electric heating system that stores heat in ceramic bricks, so that does contribute to some of the heat as well. So I'm not fully heating with the stove. But the combination seems to be working really well right now.

 

[Tron]

Granted our outside temps are in 20*-35* range, so not much heat is needed. But needless to say I am very pleased with how this stove is working.

For reference the stove is in the basement and using the house fan to circulate the air, it puts out sufficient heat to heat both basement and upstairs during these more mild temps. Additional note, I have an electric heating system that stores heat in ceramic bricks, so that does contribute to some of the heat as well. So I'm not fully heating with the stove. But the combination seems to be working really well right now.

That's not what we call "mild temps" around here, but ok.
In general, yes, with energy-dense wood and turning the stove to low, you can get 24h burns. Whether that makes sense depends on the use case. When we have sub-freezing temperatures, I use the stove to heat the home almost exclusively, so it runs higher than low resulting in 8h or so burn times, but we only have pine.

Sounds like you could save a lot of money by utilizing more heating from the stove, since those electric/brick storage systems are the absolute worst when it comes to energy efficiency. IIRC they were popular in the 70's and 80's and designed to take advantage of low-load hours in electric demand like overnight and then use the energy throughout the day, but that never really came though. And as they are resistive heaters AND lose energy with the brick storage, their efficiency is not good.

You might be able to lower your electric bill by using more of the stove to heat your home.

I've tried using the AC/furnace fan to distribute heat throughout the house, but with little effect. For one, the return air intakes are at floor level, and secondly, the ducts run through the uninsulated attic. May be different in your case.

 

[Fargo]

Sounds like you could save a lot of money by utilizing more heating from the stove, since those electric/brick storage systems are the absolute worst when it comes to energy efficiency. IIRC they were popular in the 70's and 80's and designed to take advantage of low-load hours in electric demand like overnight and then use the energy throughout the day, but that never really came though. And as they are resistive heaters AND lose energy with the brick storage, their efficiency is not good.

You might be able to lower your electric bill by using more of the stove to heat your home.

I've tried using the AC/furnace fan to distribute heat throughout the house, but with little effect. For one, the return air intakes are at floor level, and secondly, the ducts run through the uninsulated attic. May be different in your case.

You are correct about the brick storage systems are meant to charge during low load hours to keep energy cost down. But, even though my furnace hardly kicked in last month the heating bill was still higher than expected. I believe you are also correct that the brick storage system is inefficient and it still took a lot of energy to keep the bricks charged. Next year I may try to experiment with turning the furnace system off and heating with the wood stove.

I'm in the process of finishing my basement, so I am contemplating putting some of the cold air intake vents near the ceiling to help capture some of the heat off the ceiling in the room with the wood stove to circulate around the house with the furnace fan. (I'm thinking about having a closeable vent at the ceiling as well as the floor so I can open or close the vents depending on whether I am circulating heat from the stove or using the electric furnace) I am also considering installing a separate gravity vent system between floors to help with natural convection as well.

 

[bigealta]

There are guys here heating their houses with basement stoves. Search around for threads that discuss how they make it work simply.

 

[Dieselhead]

Interesting heating system, I hadn’t heard about that one. Is it something like this?

Room Heater

Steffes's room heaters warm a room in your home or commercial space using efficient and reliable Electric Thermal Storage technology.

steffes.com

 

[Fargo]

Interesting heating system, I hadn’t heard about that one. Is it something like this?

Room Heater

Steffes's room heaters warm a room in your home or commercial space using efficient and reliable Electric Thermal Storage technology.

steffes.com

Its exactly like that. I have the Steffes model 4130.

 

[Tron]

But, even though my furnace hardly kicked in last month the heating bill was still higher than expected. I believe you are also correct that the brick storage system is inefficient and it still took a lot of energy to keep the bricks charged.

I know it because we used to have one in the basement in our home built in the early 70's. Horrible energy bills and the room it was in was the warmest in the whole house. Not really what we wanted.
Ultimately we installed a heat pump in that room to at least recuperate some of that heat to get our water hot. But it was never really efficient.

 

[m37charlie]

Automatic fan controller
Consider spending ~~$40 for an Inkbird thermostatic switch for automatic control of fan. That way it’ll turn on only when you turn the thermostatic air inlet up to produce more heat when desired.
Obviously blowing hot air away from the stove does result in the bimetallic spring cooling off and demanding more air and burning more wood as a result.
Ultimately the electric fan, even with my small modification, and Ecofans do remove heat from the vicinity of the stove. But because they warm the entire area better, they result in the operator (especially if located out of line of sight and therefore not directly exposed to IR radiation photons) turning the air control DOWN, ultimately saving wood and providing a more evenly heated and comfortable house, and happier occupants - human and others.

Actually $35, but worth its weight in …these days maybe silver.

 

[m37charlie]

Attach the metal temperature probe to the top of the air plenum leading up from fan(s) just before it makes the 90 to blow over top of stove. Use Shurtape AF099. I got dialed in with ON temperature 126F, off 123. YRMV.

 

[Fargo]

Automatic fan controller
Consider spending ~~$40 for an Inkbird thermostatic switch for automatic control of fan. That way it’ll turn on only when you turn the thermostatic air inlet up to produce more heat when desired.
...
Actually $35, but worth its weight in …these days maybe silver.

That's an interesting option. Since I'm still new to wood stoves, I'll experiment with the stove itself for a while first. I am kind of a simple guy, so I'm not always the first to jump on electronic devices. But I do like that as an option. I'll keep this in mind. Thank you.

 

[m37charlie]

That's an interesting option. Since I'm still new to wood stoves, I'll experiment with the stove itself for a while first. I am kind of a simple guy, so I'm not always the first to jump on electronic devices. But I do like that as an option. I'll keep this in mind. Thank you.

It’s just a temperature controlled switch. I have the display hanging from a nail in the wall so I can easily see it.
Along with the Ecofans, glancing at it gives me a visual indications of heat output.

 

[Murray01]

Automatic fan controller
Consider spending ~~$40 for an Inkbird thermostatic switch for automatic control of fan. That way it’ll turn on only when you turn the thermostatic air inlet up to produce more heat when desired.
Obviously blowing hot air away from the stove does result in the bimetallic spring cooling off and demanding more air and burning more wood as a result.
Ultimately the electric fan, even with my small modification, and Ecofans do remove heat from the vicinity of the stove. But because they warm the entire area better, they result in the operator (especially if located out of line of sight and therefore not directly exposed to IR radiation photons) turning the air control DOWN, ultimately saving wood and providing a more evenly heated and comfortable house, and happier occupants - human and others.View attachment 346260
Actually $35, but worth its weight in …these days maybe silver.

I use something similar to run my electric smoker, turns the heater on/off depending on the set point.

 

[Highbeam]

Well the stove is advertised to burn for 30 hours so I think it is reasonable to expect at least 24 hours. I get 24 cycles on my BK too. Some get well over the rated 30.

Glad the technology is working for you. When your cat wears out, one of the first things you might notice is the inability to get those long burn times since the low burn capability goes away first. Start watching that after about 10,000 hours of burn time. Popping in a new cat is super easy and brings back that missing performance immediately.