Need help getting more heat from stove into room/house.

[KennyK]

Hi all,

Just got the Jotul F100 up and running and am totally enjoying it, but I think there may be ways to get more heat into the stove room and therefore other parts of the house. My stove is sitting on the hearth with just the rear legs in the firebox (see pic below) and has heat shields on three sides. I have about 14 inches of depth in the firebox behind the stove and that is where a lot of heat seems to be getting trapped (it's warm and toasty when I put my hand back there!). I have an insulated blockoff plate, but the company that did the liner install didn't seal that off completely with high temp silicone (it's just kind of wedged up there), so sealing that may help, but I want to wait to do that until after stove inspection in case inspector wants to take a look, and I'm not sure that's the main issue. I have a ceiling fan in the stove room that I'm running in reverse, which helps and I put a box fan facing the stove, which also helps, but I wonder if there are other better solutions. The last two nights I've gotten the stove room up to 71 degrees and would like to get it warmer (and think I can). Some things I'm thinking about are getting an ecofan and perhaps even place it blowing behind the stove into the firebox to blow air out of there. I seen some people here say these don't do much, but these two seem to get some good reviews:
https://www.amazon.com/dp/B0762PR6XT/?tag=hearthamazon-20

https://www.amazon.com/dp/B012U9E3JW/?tag=hearthamazon-20

I also wonder if there's some sort of a blower I could do, though I prefer the idea of no electricity like with the ecofans.

Thoughts?

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[HomeinPA]

If it's all masonry behind the stove maybe a piece of sheet metal from side to side, hearth to lintel, wrapped behind the stove with Roxul insulation behind it to reflect the heat back and/or keep it from being absorbed by the masonry behind it. Paint the sheet metal flat black.... or pink, whatever you prefer.

 

[lsucet]

I will try to seal that area that you mentioned before. you need to stop heat loss there. Ecofans is hard to tell how much will help but something is better than nothing. in my experience, ceiling fan in the same room of the stove unless if far away cause is a big room don't help much cause is pushing the heat back to the stove and not letting too much heat out from hearth. Possibly i am wrong but that is my experience. A fan at floor level blowing to the stove room can make a better job in my opinion or ceiling fans in far rooms. try reverse of forward, what works for me maybe don't work for you, but for sure i will seal that area as soon as possible. Any gap in that area will prevent the heat to expand into the room. Hope this help

 

[KennyK]

I will try to seal that area that you mentioned before. you need to stop heat loss there. Ecofans is hard to tell how much will help but something is better than nothing. in my experience, ceiling fan in the same room of the sove unless if far away cause is a big room don't help much cause is pushing the heat back to the stove and not letting too much heat out from hearth. Possibly i am wrong but that is my experience. A fan at floor level blowing to the stove room can make a better job in my opinion or ceiling fans in far rooms. try reverse of forward, what works for me maybe don't work for you, but for sure i will seal that area as soon as possible. Any gap in that area will prevent the heat to expand into the room. Hope this help

Thanks! What do you think about using a blower like this (or some other similar blower): https://www.amazon.com/dp/B005O8HNMQ/?tag=hearthamazon-20

If it's all masonry behind the stove maybe a piece of sheet metal from side to side, hearth to lintel, wrapped behind the stove with Roxul insulation behind it to reflect the heat back and/or keep it from being absorbed by the masonry behind it. Paint the sheet metal flat black.... or pink, whatever you prefer.

Thanks! The masonry in the firebox (sides and back) is all covered with a thick metal plate (perhaps cast iron). I'm not sure if that makes too much of a difference and I did think about what you suggested of closing that all off with sheet metal. My brother has an old surround that he's no longer using from an old Vermont Castings stove he used to have that I may be able to modify for the purpose, as it already has a whole cut for the stove pipe to go through. Or if that doesn't work, might do as you suggest.

 

[lsucet]

Thanks! What do you think about using a blower like this (or some other similar blower): https://www.amazon.com/dp/B005O8HNMQ/?tag=hearthamazon-20

For more that i will like to give you an input on it, I have to tell you that i have no experience with something like that. Possibly other member will chime.

 

[begreen]

I also wonder if there's some sort of a blower I could do, though I prefer the idea of no electricity like with the ecofans.

I have tried one of these cheap fans on Amazon. They are from China and not too honestly represented. I am dubious of the cfm ratings. The fan I got was wired backwards too. I had to reverse the wiring. It's performance next to the old Caframo is anemic.

The first one that you listed looks a little better. At least they provide full specifications. The second one looks tiny.

 

[HomeinPA]

Thanks! The masonry in the firebox (sides and back) is all covered with a thick metal plate (perhaps cast iron). I'm not sure if that makes too much of a difference and I did think about what you suggested of closing that all off with sheet metal. My brother has an old surround that he's no longer using from an old Vermont Castings stove he used to have that I may be able to modify for the purpose, as it already has a whole cut for the stove pipe to go through. Or if that doesn't work, might do as you suggest.

If there is already a plate in place maybe just pull it out a bit and insulate behind it to keep heat from transferring to the masonry. Combine that with sealing the damper area (use the roxul insulation again) and that should keep all the heat inside.

As far as a fan....I don't know what the layout of the rest of the room is but I would go get a small tower fan and place it off to one side, slightly forward of the stove, possibly beside a chair or end table and direct the air towards the stove. It'll blow around the back and out the other side and front and you have an inexpensive blower.

 

[Ashful]

I tried heating for several years with Jotul Firelight 12’s (predecessor of current Firelight 600) in fireplaces, and learned a few things. The parameters were a little different than yours, but I suspect there are some commonalities.

My fireplaces were all masonry, and on an exterior wall. Meanwhile, the cast iron Jotuls are highly radiant heaters. A large part of the heat radiated off the sides, back, and top of the stove was soaked up by the masonry of the fireplace surrounding it. I could see this by measuring the temperature of the stone work, both inside and outside the house.

I figured a heat shield, spaced an inch off the masonry, would go a long ways toward improving the situation, but I sold the stoves before getting to that. I replaced them with cast iron clad steel stoves (similar design to Jotul F50, I believe?), and my ability to put heat into the house improved dramatically. I also don’t get my stone work searing hot, anymore, while dumping heat into my back yard.

Even with the convective stove, I still run a fan on the stove, to move heat out into the room. This makes a huge difference.

It sounds like you have a steel firebox, which should be better than my masonry fireplaces, but perhaps your suffering a bit from the same radiant heating phenomenon.

 

[KennyK]

I have tried one of these cheap fans on Amazon. They are from China and not too honestly represented. I am dubious of the cfm ratings. The fan I got was wired backwards too. I had to reverse the wiring. It's performance next to the old Caframo is anemic.

The first one that you listed looks a little better. At least they provide full specifications. The second one looks tiny.

I got the first heat powered stove fan I linked to in the mail today, and it's definitely helping a bit. I've been playing with the placement on the back side and back middle off the stovetop as you see in the pics here. What I've noticed (from feel not an official reading) is the area behind the stove in the firebox seems to not be quite as hot, which I believe is because the fan is getting some of the trapped hot air out of there, and moving some more heat from the back of the stove into the room. I'm now running this instead of a box fan, which is nice because there's no noise. This said, I'm still not getting the temps I want in the room. With the stove running at around 500, the stove room is at 73 or 74. I'm wondering if a second one of these fans might be a good idea and I can put one one either side of the back of the stove.

I am also debating HomeinPA's idea here:

If it's all masonry behind the stove maybe a piece of sheet metal from side to side, hearth to lintel, wrapped behind the stove with Roxul insulation behind it to reflect the heat back and/or keep it from being absorbed by the masonry behind it. Paint the sheet metal flat black.... or pink, whatever you prefer.

As HomeinPA wrote, I'm thinking to run sheet metal with roxul behind it behind the stove with a 6" hole for the stovepipe, like a blockoff plate, but covering up the whole firebox opening. If I do this, can I put it right up by the back of the stove, around where the stovepipe collar is, or do I need to leave some more space between the stove and the sheetmetal?

Thanks!

 

[KennyK]

Question: I am going to make a steel piece with roxul on the back to block off the firebox in my fireplace that seems to be trapping a lot of hot air. Can I put that steel right up against the back of the stove? I was thinking it would touch the existing heatshield on the back of the stove, with a hole cut out around the six inch pipe that exits the stove. Is there any reason I'd need to leave an airspace between the stove and that steel? I'll be using 22 gauge steel.

Would I attach the roxul with high temp silicone? I saw a few different kinds of roxul - do I need the roxul "safe 'n sound"?

Thanks!

 

[Ashful]

Not an answer to your question, but I have to ask... wouldn’t it be a lot easier to just put a blower kit on that stove, or a fan to move the heat out? I have my stoves in deep fireplaces (one is almost big enough to park a SmartCar in it), and I have no issue moving the heat out with the blowers running on low.

 

[KennyK]

Not an answer to your question, but I have to ask... wouldn’t it be a lot easier to just put a blower kit on that stove, or a fan to move the heat out? I have my stoves in deep fireplaces (one is almost big enough to park a SmartCar in it), and I have no issue moving the heat out with the blowers running on low.

Ashful, your question, and perhaps some guidance from your expertise is greatly appreciated! Perhaps your suggestion would be easier, but I need a little help in navigating what kind of blower or fan. I did get an eco fan and it is definitely getting some of the heat out of the fireplace area, but there's still a lot trapped back there (putting my hand back there is like going into a toasty sauna!). I have the fan to one side of the stove and wonder if I should get a second for the other side, or if I'd be better buying a blower. If a blower, I'm really not sure what kind would be good for my Jotul F100 - any thoughts? I linked to one above in this thread that @begreen said was poorly made. Any suggestions for something good would be appreciated. My thought on the steel plate behind the stove was taking @HomeinPA's suggestion. I thought it would stop a lot of the heat from just hanging out behind the stove and then my little (and very quiet) eco fan alone might do the trick. That said, I'm up for anything that will best get the heat out into our living space (and preferably not be too loud). Thanks!

 

[Ashful]

I’d post a separate thread titled something like, “blower for Jotul 100”, to get a more targeted response on that question. It will catch the eye of the Jotul 100 owners.

When I ran Jotul 12’s, I found that a lot of heat was radiating off the back and sides, and being soaked up by my stonework. Part of my solution was to put a simple square (about 24 x 30 inches) on the back wall of my fireplace behind the stove, using those 1 inch ceramic spacers designed for stove wall shields. This acted as a simple reflector, and dramatically reduced the amount of heat soaked up by the wall. Then I placed a small desk fan on the floor, across the room a ways, pointed toward the stove. This pushed cold air along the floor toward the fireplace, which would displace the hot air which ends up trapped in the fireplace. With a block-off plate up higher in the fireplace opening, that hot air would just roll out, as the cool air being pushed by that fan displaced it. I found that to work very well, but since my stove was all the way back inside the fireplace, I still had enormous losses from the sides of the stove radiating into the masonry on either side of it. I didn’t want to repeat the reflector shields on the sides (cosmetic), so I never dealt with that.

I’m not saying any of this is better than your solution, but it’s another option to consider. It’s also easier, and less visually intrusive.

 

[KennyK]

I’d post a separate thread titled something like, “blower for Jotul 100”, to get a more targeted response on that question. It will catch the eye of the Jotul 100 owners.

When I ran Jotul 12’s, I found that a lot of heat was radiating off the back and sides, and being soaked up by my stonework. Part of my solution was to put a simple square (about 24 x 30 inches) on the back wall of my fireplace behind the stove, using those 1 inch ceramic spacers designed for stove wall shields. This acted as a simple reflector, and dramatically reduced the amount of heat soaked up by the wall. Then I placed a small desk fan on the floor, across the room a ways, pointed toward the stove. This pushed cold air along the floor toward the fireplace, which would displace the hot air which ends up trapped in the fireplace. With a block-off plate up higher in the fireplace opening, that hot air would just roll out, as the cool air being pushed by that fan displaced it. I found that to work very well, but since my stove was all the way back inside the fireplace, I still had enormous losses from the sides of the stove radiating into the masonry on either side of it. I didn’t want to repeat the reflector shields on the sides (cosmetic), so I never dealt with that.

I’m not saying any of this is better than your solution, but it’s another option to consider. It’s also easier, and less visually intrusive.

Thanks Ashful! Do you think if I did my approach, there is anything wrong with having that block off shield right up against the back of my stove, from fireplace floor to lintel, up against the existing heat shield on the back of my stove, and touching the stove pipe? Is there any need to leave some space between this and the stove?

 

[Easy Livin’ 3000]

Thanks Ashful! Do you think if I did my approach, there is anything wrong with having that block off shield right up against the back of my stove, from fireplace floor to lintel, up against the existing heat shield on the back of my stove, and touching the stove pipe? Is there any need to leave some space between this and the stove?

I'd leave a gap. Let the stove radiate as designed, then move that hot air away from the stove into the room.

Think of it this way: The potential downside of touching the insulated sheet metal to the stove is overheating the back of the stove and ruining it. Compare this to whatever upside you think is possible.

 

[KennyK]

I'd leave a gap. Let the stove radiate as designed, then move that hot air away from the stove into the room.

Think of it this way: The potential downside of touching the insulated sheet metal to the stove is overheating the back of the stove and ruining it. Compare this to whatever upside you think is possible.

Very sound advice! Does it matter if the steel sheet touches the black stove pipe? I notice on my blockoff plate (which the company that did the liner install made) at the damper the opening hole is a little larger than the 6 inch liner, and the insulation is touching the liner, but not the metal plate. Also, if I put roxul behind the sheet metal, can/should I attach that to the metal with high temp silicone?

 

[Easy Livin’ 3000]

Very sound advice! Does it matter if the steel sheet touches the black stove pipe? I notice on my blockoff plate (which the company that did the liner install made) at the damper the opening hole is a little larger than the 6 inch liner, and the insulation is touching the liner, but not the metal plate. Also, if I put roxul behind the sheet metal, can/should I attach that to the metal with high temp silicone?

It's fine if the sheet metal touches the black stove pipe. No problem there. It will conduct heat where it touches, but I doubt that would cause any issues in this application.

I'd use spray adhesive to attach the Roxul to the sheet. I've attached a picture of the stuff that came with liner insulation. Just spray both the Roxul and sheet metal OUTSIDE.

Silicone might work fine, but unless you spread it thin and get good adhesion over a wide area of the Roxul, it might just flop down.

 

[KennyK]

It's fine if the sheet metal touches the black stove pipe. No problem there. It will conduct heat where it touches, but I doubt that would cause any issues in this application.

I'd use spray adhesive to attach the Roxul to the sheet. I've attached a picture of the stuff that came with liner insulation. Just spray both the Roxul and sheet metal OUTSIDE.

Silicone might work fine, but unless you spread it thin and get good adhesion over a wide area of the Roxul, it might just flop down.

View attachment 221749

Thanks! Interestingly though, I just looked up this product and it is only heat resistant to 150 degrees fahrenheit, which seems kind of low to me for how hot the metal would get, but perhaps I'm wrong. Here's a link to the product: https://www.3m.com/3M/en_US/company...e-Spray-Adhesive/?N=5002385+3293242460&rt=rud

 

[Easy Livin’ 3000]

Thanks! Interestingly though, I just looked up this product and it is only heat resistant to 150 degrees fahrenheit, which seems kind of low to me for how hot the metal would get, but perhaps I'm wrong. Here's a link to the product: https://www.3m.com/3M/en_US/company...e-Spray-Adhesive/?N=5002385+3293242460&rt=rud

It adhered the mineral wool blanket to the liner, and it's still there three seasons in! The liner gets way hotter than 150.

It actually came with the blanket kit from the chimney supply store. I guess it probably just melted into the mineral wool and formed a permanent burned/melted together bond. If it worked there, i bet it'll work in your application. So long as it gets adhered to start. It's what I'm gonna use on my permanent block off plate.

 

[Ashful]

I'd leave a gap. Let the stove radiate as designed, then move that hot air away from the stove into the room.

Think of it this way: The potential downside of touching the insulated sheet metal to the stove is overheating the back of the stove and ruining it. Compare this to whatever upside you think is possible.

ED already said what I would have said, but he did it better... ‘cuz I’m on Sapphire martini no.2 (thanks, begreen!).

I would be leery of the spray adhesive, myself, but if Ed says it’s working for him...

 

[Easy Livin’ 3000]

ED already said what I would have said, but he did it better... ‘cuz I’m on Sapphire martini no.2 (thanks, begreen!).

I would be leery of the spray adhesive, myself, but if Ed says it’s working for him...

I was skeptical myself of the spray adhesive. Had I not been in a time crunch with the $400/day lift sitting there, I'd definitely have posted the question here, and pondered myself half crazy. But, due to the time pressure, I just bit the bullet, figured, the chimney supply guys who sell hundreds of the liner insulation kits must know what they are doing when they include it with the kit.

Perhaps when the day comes to pull the liner I'll find that it failed. I doubt it, but I can't claim knowledge until I do. I'll have to punt that one to the pros here.

Here's a link to the exact supplier and their picture online. Rockford shows the same stuff in their kits.

http://www.woodlanddirect.com/Chimney/Liner-Tools-Insulation/6-Insulating-kit-25-feet