Running blowers on stove or not?

[ohlongarm]

Last night was the first time running the blowers on my stove all night.Don't like paying utility companies anymore than I have to.My observation was this,I ran the blowers on low about 12 hours with a 90% full load couldn't get 100% due to the odd sized pieces I was burning.My house was 76 when I turned them on and 75 about 12 hours later,stovetop was in low 300's and the cat was just inside the active zone.What are the advantages or disadvantages to running or not running the blowers and how does it affect the stoves burning performance. I have only run the blower previously for quick warmups ,no more than an hour.

 

[HotCoals]

I would think you are the only one who can tell in your house if the blowers help with your layout.
I don't think just because the blowers are on that you gain heat..no way..but you could be pushing the heat around some..to other rooms maybe.
Certainly the fire inside the box does not change just because the blowers are on.
Some BK owners say it makes the t-stat open more often..I have not seen that with my setup.
I rarely run the fans..I'm like you..don't want to give the power company any more then I have to.
Wife likes the cieling fan on low though...I think she likes the tropic breeze with her wine!

 

[DanCorcoran]

I don't think you get MORE heat over the course of 12 hours, I think you just get it faster. It accelerates the heat loss from the stove, so you get more heat in the room faster, but it also consumes the wood load faster. Then again, maybe it just sends less up the flue. If that's true, you might end up with more creosote. Who knows?

 

[HotCoals]

I don't think you get MORE heat over the course of 12 hours, I think you just get it faster. It accelerates the heat loss from the stove, so you get more heat in the room faster, but it also consumes the wood load faster. Then again, maybe it just sends less up the flue. If that's true, you might end up with more creosote. Who knows?

Could you explain to me how that happens?
To me the fire in the stove does not change from fans outside it.
Even if it cools the stove a lot the fire don't care..unless it cools a t-stat stove enough to open the air.

 

[Beer Belly]

When we got our house (1,700 sq. ft. +/- Split Level Ranch), the first thing my Wife wanted was a Wood Burning Insert.....went 2 years with the Insert (Avalon Ranier) on it's own....been 2 years with the Blower.....big difference, moves the warm air right up to the bedrooms....can't go without it since....a little noisey on full boogey, but the savings on oil is worth it.

 

[MrWhoopee]

When we got our house (1,700 sq. ft. +/- Split Level Ranch), the first thing my Wife wanted was a Wood Burning Insert.....went 2 years with the Insert (Avalon Ranier) on it's own....been 2 years with the Blower.....big difference, moves the warm air right up to the bedrooms....can't go without it since....a little noisey on full boogey, but the savings on oil is worth it.

What he said. When the power is out, the living room stays toasty, but the nether portions of the house get chilly. The blower improves distribution of heat, not the amount liberated. I use the blower on the stove sparingly because it is noisy. My ceiling fan and Thru-wall fans are always running. I suppose it's possible that the blower could draw enough heat out of the firebox to cool it below ignition point of the secondaries, but seems unlikely. I don't have a cat, but I believe that once it has reached ignition, it generates enough heat to keep itself going until the fuel in the smoke is exhausted. :lol:

 

[DanCorcoran]

My stove-top reading drops 100 degrees in 10-15 minutes after turning on the blower. That heat is being moved into the room. Whether it comes from less going up the flue or from fuel being consumed faster, I have no idea. We do know that reduced air supply causes slower burning, but if or how increased removal of heat could cause faster burning, I don't know (and somewhat doubt). That leaves less heat going up the flue.

 

[madison]

My stove-top reading drops 100 degrees in 10-15 minutes after turning on the blower. That heat is being moved into the room. Whether it comes from less going up the flue or from fuel being consumed faster, I have no idea. We do know that reduced air supply causes slower burning, but if or how increased removal of heat could cause faster burning, I don't know (and somewhat doubt). That leaves less heat going up the flue.

Well stated Dan, +1

 

[Treacherous]

My stove-top reading drops 100 degrees in 10-15 minutes after turning on the blower. That heat is being moved into the room. Whether it comes from less going up the flue or from fuel being consumed faster, I have no idea. We do know that reduced air supply causes slower burning, but if or how increased removal of heat could cause faster burning, I don't know (and somewhat doubt). That leaves less heat going up the flue.

I can drop temps pretty fast with fan on hi on my Lopi as well.

 

[Lumber-Jack]

The more air you blow over the hot metal surfaces of your stove, the more heat you'll be able to extract, it's simple physics.

My stove came with a factory supplied blower and we always used it. The extra heat extraction from the stove is well worth the electricity to run the blower, especially when running the stove hot.
This winter the blower started getting noisy so I did my regular cleaning of the squirrel cage fans, but the noise remained. The unit is on it's fourth year so it's likely the bearings starting to go. Anyway, I couldn't stand the noise so I bought a cheap $14 fan that I mounted to the wall behind the stove and started blowing air past the flue exit and over the top surface of the stove. Boy does that ever work well! The wall mount fan is quieter and moves way more air than the blower fan use to and the extra heat that comes off the stove is very noticeable.

 

[HotCoals]

My stove-top reading drops 100 degrees in 10-15 minutes after turning on the blower. That heat is being moved into the room. Whether it comes from less going up the flue or from fuel being consumed faster, I have no idea. We do know that reduced air supply causes slower burning, but if or how increased removal of heat could cause faster burning, I don't know (and somewhat doubt). That leaves less heat going up the flue.

I can drop temps pretty fast with fan on hi on my Lopi as well.

Yep..the fans will speed up the transfer of heat off the stove..and push it around.
But the blowers will sometimes make the temp gauge look like it dropped more then it really did because of the cooler air being blown across the bi-metal coil.
Compare temps with a IR gun if you have one.
But yeah..some stoves will drop more then others from the transfer of heat from the fans.
But the fire inside will not change.
I have read from smarter guys then me that fans cooling the stove might actually slow the fire .
Reason being the hotter the insides the more the fire wants to burn...probably more so yet in a tube stove.

 

[kenny chaos]

I wouldn't light my Lopi Liberty if the blower wasn't working, unless I had to.
Kenny

 

[WoodpileOCD]

I always run my blowers at night because I want as much heat as possible coming off the stove and being forced out of the stove room. When I'm around the stove and in and out, it depends on the temps in the house. I can definitely heat the room/house up more with the blowers on but sometimes the noise gets a bit much. Most of the time, its like white noise that I don't even hear after awhile but other times it is annoying.

As far as the burn goes, I can't tell any difference in times at all. I enjoy the stove more without it when I'm in the room but it is not as efficient I'm convinced.

 

[MarkinNC]

I stopped using my blower for the most part. If the house is a little cool in the morning and I want to push the heat to the back of the house a little quicker, I'll turn it on for a while. What I discovered is that a convective stove like I have actually convects and my stove is in the far corner of my home. Also the stove room does seem as hot with the blower off, a softer heat if you will. The humidity gauge drops more with the fan on. And lastly, I agree the fire seems a little more responsive with the blower off. the only analogy I can think of is that is kind of like turning the air conditioning on in a car.

 

[HotCoals]

I always run my blowers at night because I want as much heat as possible coming off the stove and being forced out of the stove room. When I'm around the stove and in and out, it depends on the temps in the house. I can definitely heat the room/house up more with the blowers on but sometimes the noise gets a bit much. Most of the time, its like white noise that I don't even hear after awhile but other times it is annoying.

As far as the burn goes, I can't tell any difference in times at all. I enjoy the stove more without it when I'm in the room but it is not as efficient I'm convinced.

Yep..
Some guys claim they have better luck when wanting to move hot air around by putting fans in the bottom of a doorway and blowing cooler air into the stove room..and just leave their stove fans off.
If you really want to look goofy hang 2ft. strips of toilet paper all over the house (mostly in doorways)and watch how much they move with fans on or off and by using ceiling fans,box fans.

 

[MrWhoopee]

My stove-top reading drops 100 degrees in 10-15 minutes after turning on the blower. That heat is being moved into the room. Whether it comes from less going up the flue or from fuel being consumed faster, I have no idea. We do know that reduced air supply causes slower burning, but if or how increased removal of heat could cause faster burning, I don't know (and somewhat doubt). That leaves less heat going up the flue.

On further consideration, I think it may be possible that using the blower may actually increase the total amount of heat transfered to the room(s) by extracting more heat from the exhaust. The actual stove top is underneath what we see as the stove top. It's a double wall affair with the blower pushing air between the two. The circulation of air between the inner and outer skins transfers the heat (which has already left the firebox) to the air instead of allowing it to convect and radiate to the outer skin. And, of course, the internal baffles isolate the actual stove top from the top of the firebox. Cooling the inner skin (the actual top of the baffle chamber) may actually increase the heat transfer out from the baffles by increasing the temperature difference (gradient) between the exhaust gasses and the top, resulting in more heat extracted from the exhaust. None of this affects the temperature in the combustion chamber because it all happens after the gasses have left the combustion chamber and entered the baffle chamber. If this is actually the case, a drop in stack temperature should be observed with the use of the blower. Time for someone to take some measurements and post the results.

 

[HotCoals]

You're on track I think..I have noticed stack temp drops on my BKK with fans on.
On long slow burns I need all the heat I can get in my stack..it usually only runs about 250f 18" up..single wall.
I have seen my fans drop it to 225...just not sure it's just from the fans..but probably.
I rarely ever run them though.

 

[rdust]

And lastly, I agree the fire seems a little more responsive with the blower off.

For a non cat I see it this way, for a non cat to burn right(achieve secondary combustion) the internal temps of the firebox have to be 1200ish? If you're running the fans it's harder to maintain that high internal temp required for secondary combustion since you're scrubbing heat off the stoves surface. With the fans off the fire can reach those temps easier, with my Lopi I usually turned the fans off on reload until I had a fire well established.

The Endeavor IMO has one of the best heat transfer systems around, pulls the air around the firebox and dumps it out between the cook top and step top, I always loved the way it moved heat around the house.

When it's cold I always run my fans on low, really cold I run them on medium or so if I need to warm the house up. Shoulder season I rarely run them.

 

[simple.serf]

We always run our fan. We are trying to heat a 2000 sq ft raised ranch. I have a grate in the ceiling above with a fan in it to get some warm air upstairs. The goal is only burning oil for the domestic hot water this year. I have found I can't do that when it gets much below 10*.

Every little bit of heat from the stove helps.

 

[rdust]

I have found I can't do that when it gets much below 10*.

Oh sure you can you just need to lower the thermostat. I keep mine low enough so I know there is no way it'll run unless I'm gone. I keep mine set at 60*, I'd have to screw up pretty bad to get that low. :lol:

 

[Treacherous]

If I run my fans on high during borderline secondary combustion it will begin to bring it out of this phase. I usually don't let them run during a reload until I get around 450-500 degrees.

And lastly, I agree the fire seems a little more responsive with the blower off.

For a non cat I see it this way, for a non cat to burn right(achieve secondary combustion) the internal temps of the firebox have to be 1200ish? If you're running the fans it's harder to maintain that high internal temp required for secondary combustion since you're scrubbing heat off the stoves surface. With the fans off the fire can reach those temps easier, with my Lopi I usually turned the fans off on reload until I had a fire well established.

The Endeavor IMO has one of the best heat transfer systems around, pulls the air around the firebox and dumps it out between the cook top and step top, I always loved the way it moved heat around the house.

When it's cold I always run my fans on low, really cold I run them on medium or so if I need to warm the house up. Shoulder season I rarely run them.

 

[kenny chaos]

If I run my fans on high during borderline secondary combustion it will begin to bring it out of this phase. I usually don't let them run during a reload until I get around 450-500 degrees.

When do you eat? :lol:

 

[OhioBurner©]

Depends on what kind of stove you have I guess... on my Rockland which is flush with the hearth, if you dont run the blower you dont get hardly any heat lol. Only time that blower isnt on high is if we are sitting next to it watching a movie, then we turn it down to low.

 

[simple.serf]

I have found I can't do that when it gets much below 10*.

Oh sure you can you just need to lower the thermostat. I keep mine low enough so I know there is no way it'll run unless I'm gone. I keep mine set at 60*, I'd have to screw up pretty bad to get that low. :lol:

Haha! We have ours set at 55 and it has been firing up upstairs!. Project for this spring is more insulation and new windows. Sometimes I think the single pane windows are just as bad as a hole in the side of the house. I put some new storms on, which has helped when we get the 40 mph winds.

 

[eclecticcottage]

We don't run ours too often, it's noisy and in this small of a house, you can hear it in the bedroom. Just when we need to take the chill off if we let the stove go cold when it's in the 40's, or when the stove tries to creep past 750.