Most effective way to increase stove efficiency?

[michael]

When answering this question, think along the lines of heating an entire house. I believe that is generally the goal of most who post on this forum. What has been your own experience? Opinions?

An Eco fan may work well in the "stove room", but will it spread heat throughout the entire house.

A ceiling fan will move heat from the "stove room" to other parts of the house, but is that air cooler surface air?

Some have suggested an economical box fan pointed directly at the stove front is the way to go.

Maybe a stove blower is the best single investment for a stove owner?

 

[Sundeep Arole]

There is one option I am looking at quite seriously, though no way to do it this year, possibly next year. It is called a heat recovery ventilation system (aka air-to-air exchanger.) These are designed mostly for providing ventilation in airtight buildings or houses, but rather than simply bring outside air in, they replace a given amount of inside air with outside air in a balanced way, and send the two air streams through a heat exchanger which recovers most of the heat from the outgoing air to preheat the air coming in. I am looking at hooking up a system with the intake in the family room/DR/kitchen area, where the woodstove will heat, and placing the exhaust in the bedrooms. Note in these systems the exhaust is really fresh outside air, pre-heated with the recovered heat from the air that is sent out. These systems can be set at a given rate of air exchange.

My house isn't all that airtight, but in this case my intention is to try and provide adequate ventilation, achieve some minimal humidity control, and ciculate some of the woodstove heat. Some of these systems can also be hooked up so that the heat from the bathroom exhaust air and range hood exhaust is also recovered, but since those things have blowers, it is trickier to duct those things in the intake in such a way as to not interfere with the balanced air exchange the unit is intended to provide.

Downside - well, these aren't cheap, and probably need to be installed by a pro, which makes even more expensive. They also cant just be hidden away in the attic, so you need some place where you can put the system.

 

[Roospike]

Ceiling fans by a big margen , than maybe a stove blower. I have both tho i could do with out the blower if needed i think it helps kick the heat away from the stove for the Ceiling fans to take over. I'm sure box fans and such would be ok if you could get them high enough to do any good. I heat my whole 1800 sq ft house with our wood stove 24/7 and use wood alone for heat. "out with the gas" my wife always tells my son and i ........ i guess it was natural gas she was talking about , right ?

 

[Eric Johnson]

I agree with Dylan. You might get more smoke with a full load at first, but as soon as it clears off, you'll get a longer, cleaner burn. I think it's best, under this scenario, to establish a healthy bed of coals before filling 'er up, though.

 

[wg_bent]

Well, here's a related question:

After a while, there gets to be a lot of coals at the bottom of the stove, and I tend to just let it sit without a reload in order to let some the the coals burn down a bit...otherwise it seems to build up. The owners manual suggests that more frequent and smaller loads burned hotter is best firing technique, but your all suggesting here that larger loads are better.

So, I guess some conflicting input here, but also, when I'm letting the coals burn, it seems prudent to turn the blower down or even off in order to keep firebox temps high, thus keep efficiency up also. Would you all agree with this process?

Here's where the experience pays off that I don't have.

Thanks,

 

[Eric Johnson]

Almost everyone recommends smaller, hotter fires, usually for reasons relating to clean burning and less creosote as a result. Dylan and I are just thinking outside the firebox.

As to coals, IMO, the more the better. If you can reduce a firebox full of wood into a firebox half full of coals, then you're doing something right. If you're worried about squandering the heat with a blower, why not rig it up to a thermostat?

 

[wg_bent]

Well, I guess in thinking about my question a bit more, maybe the stove is already taking care of it. Once the temp drops too low, the blower shuts off automatically.

I was just trying to tweek efficiency of the burn. Just to get out that last .05% of burned smoke! ;-)

 

[Eric Johnson]

I have to empty my boiler ash pan daily (and more often when it's bitter cold) in order to maintain efficiency and relatively clean burning. And the grates have to be kept clear as well. It's not hard to do given the way it's designed, but I don't think it would be possible, for the reason Dylan described, if it didn't have a grate and an ash pan. Also, since I have a forced draft blower for combustion air, coals clogging up the airflow has never been a problem, although sometimes I get more combustion at one end of the firebox than the other.

 

[Rhone]

If I understand your title, you mean what's the best investment to spread the heat from your stove. I have an insert, in the past used 2 stoves. Blowers, hands down if your stove is a convection wood stove. If it's a stove that you can put blowers on, but doesn't have the channels for convection it won't be much different than an eco-fan or fan, etc. Is your stove a convection wood stove that has channels for convection heat, or one you can add blowers to but no channels?

I have an insert with a 150 CFM blower in it. The air coming out my insert is 150-200 degrees, and at 150 CFM it forces all the air in my house every hour fifteen minutes to be heated to 150-200 degrees, then repeats. It heats my entire house easily and gets it up to temp in no time. It also creates an air pattern, where the heat comes out my insert into the living room, swings around the corner to heat my dining room and kitchen, then shoots down the hallway into the other half of my house where it cools, drops to the floor, and comes back down my hallway into my insert to be heated again. Putting a candle at the top of my hallway, and it will blow out from the heat moving to the other side of my house. Put it at the bottom of my hallway, and it will go out there as well but this time from the cold air rushing towards the insert to be heated. That air flow spreads the heat out evenly in my house and I get situations like my living room is 73, dining room 72, kitchen 71, hallway 69, and rooms on the other side of my house 65-67. How perfect is that.

 

[begreen]

I agree with Rhone. A well designed, integral blower system can do wonders for extracting more heat from a stove and it improves room air circulation. I think it heats up a larger volume of air quicker than other methods. The key is for it to be designed into the stove and not tacked on.

 

[Corey]

Based on the allowed answers I will vote for the stove fan. All the other fans are just blowing heat around the room. If you truely want to increase the heat transfer efficiency of the stove, the best way to do that is to blow (relatively) cool room air across it. You want to take the maximum heat out of the stove but still allow for complete secondary conbustion and good draft...so it comes down to what cools faster a cup of coffee sitting on the table or a cup of coffee with a fan blowing on it. I say blow on it!

Corey

 

[Roospike]

When answering this question, think along the lines of heating an entire house.

"ME"? I myself can not see nor have ever seen where a stove fan will heat you whole house. I think some of the answers are going away from the question of whole house heating. I could turn off all my Ceiling fans and just run the stove blower and the room the stove is in will get real hot and all the other rooms in the house get cold. Someone mentioned the use of there stove blower .......... "where the heat comes out my insert into the living room, swings around the corner to heat my dining room and kitchen, then shoots down the hallway into the other half of my house" . Swings around the corner and shoots down the hall WITH A STOVE BLOWER? I need to get me that kind of blower. Wow. I think al lot of people are answering the question of the thread "Most effective way to increase stove efficiency?" with out the "When answering this question, think along the lines of heating an entire house." If not then let me know where i can get one of these whole house heating stove blowers the few has voted for vs Ceiling fans to move air better in there "whole house"

 

[Martin Strand III]

Right off the bat, I have a problem with the original question which assumes one can heat the "whole house" by burning an "efficient" fire in a stove. You know, or should know, stoves aren't meant to do this. They are mainly intended and designed as regional heaters. If your does heat your entire pad, congrats and good kudos to you; you're lucky.

I agree a FULL LOAD of DRY FUEL, beginning with a TOP DOWN FIRE (starts hot, stays hot), in a modern PHASE II STOVE, burning it as HOT AS POSSIBLE WITHOUT OVERFIRING in a CENTRAL LOCATION in your home is about as good as a mortal can do when it comes to burning wood in a metal stove.

Aye,
Marty

When the wind howls, cast downwind.

 

[Roospike]

Right off the bat, I have a problem with the original question which assumes one can heat the "whole house" by burning an "efficient" fire in a stove. You know, or should know, stoves aren't meant to do this. They are mainly intended and designed as regional heaters. If your does heat your entire pad, congrats and good kudos to you; you're lucky.

I agree a FULL LOAD of DRY FUEL, beginning with a TOP DOWN FIRE (starts hot, stays hot), in a modern PHASE II STOVE, burning it as HOT AS POSSIBLE WITHOUT OVERFIRING in a CENTRAL LOCATION in your home is about as good as a mortal can do when it comes to burning wood in a metal stove.

Aye,
Marty

When the wind howls, cast downwind.

I heat my whole house with a PE summit and have never run my stove over the lower 1/3 air supply . I also do not over load the stove , two or three splits of wood is all it takes. This is also done with a 97,000 btu steel stove. Now i cant speak for the 30,000-55,000 btu stove owners. I would think the smaller stove would have to be run "HOT" or full / over loaded to do the same heating thus is why i bought the higher btu stove.

 

[Roospike]

Roo,

Perhaps you should describe your house....age?? size?? insulation?? ambient in which you live.

Dylan

Hi Dylan, 1800 sq ft , 2 story , 100+ year old house ( remodeled ) new blown ins in walls , blown ins in attic 12"-14". Live in Nebraska , in town. Front room and din room front of house with wood stove room size 16' X 29' ~ 464 sq ft , kitchen + den/living room + office + bathrooms back side of house. 3 beedroom & one den room upstairs. Our stove is in the middle of the house next to the stairs . stove is between front room and din room. *NOTE* to Dylan , actually ..... I'm SPIKE ~ Dan and my wife is ROO . LOL

 

[Todd]

I think insert owners are going to vote for the blowers and free standing stove owners will vote for ceiling or box fans. An insert needs a blower fan or most of the heat is wasted by absorption. If you have a freestanding stove in a central location of your house you probably don't even need a fan!

I also agree that hot fires are more efficient. I use to go for the long slow burn, but since I bought a soapstone stove it seems to heat the house better when I fill her up and burn hot, and then after the fire dies the soapstone takes over.

 

[BrotherBart]

Right off the bat, I have a problem with the original question which assumes one can heat the "whole house" by burning an "efficient" fire in a stove. You know, or should know, stoves aren't meant to do this. They are mainly intended and designed as regional heaters. If your does heat your entire pad, congrats and good kudos to you; you're lucky.

Yo Marty. What region other than a whole house is the 1,800 to 3,000 square feet that the designers of these hunks of iron say they are designed to heat?

In our case we are lucky. I guess the stove is heating the 1,400 sq. ft. region down stairs and the upstairs is just along for the ride since the heat has to go somewhere.

 

[michael]

Thanks for all of the great responses! Yes, I think my original question/s were a little wordy. Might be the teacher/graduate student coming out. Still I think it was a good question, because many people have different experiences as to which method works best.

Rhone, my stove is an Avalon Mission convection stove. I haven't purchased a blower yet, but might this weekend. I have tried a box fan with mixed results. I have also thought about installing a couple of ceiling fans. Maybe the combination of a stove blower and ceiling fans is the best solution.

As for heating the entire house, I realize wood stoves are "zone" heating units. Most of us do try to heat our entire homes with our wood stoves though. My living room will maintain a constant 73* while the back bedrooms are at 66*-67*. That's acceptable to me....the wife, not so much.

 

[begreen]

All depends on the layout of the house and what one's comfort level is. Our centrally located pellet insert with blower does this task very well until it gets into the low 30's. Then running the Jotul makes up the difference. But, we have an open floorplan, no long hallways, and upstairs the 3 bedrooms and bath all radiate off of a central hallway landing. Our bedrooms are about 2 degrees cooler, which for me is just about right.

 

[Mo Heat]

I say, it all depends. I wouldn't use a hammer to remove a bolt, etc. You need the right tool for the job.

I have two large levels. Upper level has a long hallway that would require a box fan or door fan to get some air moving. I am a firm believer in using box fans ON THE FLOOR to move cool air towards the stove area. This also forces cross ventilation (air going the other direction) of warm air on the ceiling. A ceiling fan in the great room is the only thing that will move hot air down off the cathedral ceiling. Downstairs in the finished basement, my insert needs a blower to keep high(er) differential heat from leaching out of the external masonry chimney and to maximize heat transfer from the stove surfaces, that are mostly crammed into the fireplace, out into the room. An Ecofan would help balance temperatures at different spots in that large, open room when I'm not sitting right in front of the stove.

All the devices you mention have their place in different situations IMO.

 

[Rhone]

Well Michael, the best way then because you have a convection wood stove is to get its blower that attaches to the front and forces the air through the channels. You'll probably find you need less wood but the blowers take some getting used to (I like the person who said they sound like a window AC on medium).

It may not be worth it by the sounds of things. Your house sounds very efficient if you're getting that kind of even temperature without a blower. I think your wife is suffering from the phenomina I and my wife do. By morning our bedroom is 62 or so (did I tell you our house is very inefficient) and going into the room with the insert it's 68 and feels nice and comfy and I put more logs on. After a few hours we feel cold for some reason even though the room is the same temperature, so we turn up the insert and get it to 70 in there. A few hours later that's not enough we get it to 72, and on and on. Eventually at night my wife isn't comfortable unless it's 80 in there and if I've spent the day there me to. If at any point I go into the bedroom to watch a show, go into the cold basement for a period of time I adjust to the cooler temperature and now going into the living room and getting hit with 80 degree heat takes the wind out of me I feel so hot. I wonder what the name is, regardless if that's what happens to you and your wife a blower isn't going to fix it.

 

[emma]

Hi this is emma my house is a new build and has insulated floors 2.5 in silverback insulation 8x4 sheets, between the rafters i have 4in silverback insulation sheets fitted tight. The attic space has three rows of fibreglass insulation. The exterior walls are all insulated with 8x4 insulation/plasterboard. i have double glazed windows. The house is a dormo house.
The area of the house is 221.73m2 the internal volume is 512m3.
I have 4 x solar vacumned tube panels (4x18 tubes), i know that a panel with 10 tubes can provide 8, 416m2K. i want your expert opinion would a stove with back boiler 16KW along with the solar heating would i have sufficent ambient temperature.

 

[begreen]

Hi Emma, welcome. Can you re-post this in a new topic thread? It is likely to get more attention that way. If you can post some pictures of the house that would be great. I'd love to see them.

 

[fossil]

Howdy Michael - I think perhaps you're using the term "efficiency" when you might really be talking about "effectiveness". There's little or nothing a consumer/owner/operator can do to improve the efficiency of a woodstove...that's for the most part a function of the design of the stove. The efficiency of the overall installation depends on how well thought out and put together it is (stovepipe/chimney configuration & materials). Effectiveness, on the other hand, would involve just how well the stove serves its intended purpose in the specific installation, which is what it seems to me you're really addressing here...does the stove provide a desired amount of heat to the desired area(s)? I have two free-standing woodstoves, one in our house, and one in my workshop. The Lopi in the house has a factory blower kit on it, and I'm completely sold on having it. No, it's not silent, but it provides a terrific benefit. The stove is in a large room with a vaulted ceiling (~18' at the interior peak). Without the blower, the convective heat from the stove would just move immediately up to the ceiling. The blower does a great job of pushing that hot air out from the stove to mix with the room air as it inevitably finds its way up. The variable speed blower combined with a good ceiling fan will make for a system that can keep the space in which the stove is installed as comfy as can be. Woodstoves are basically "space heaters"...they do a great job of heating the area immediately around them. Trying to distribute some of that warmth to other rooms in our homes is a challenge for all of us. We use our installed electric furnace fan to circulate the air...not a perfect method, as the air passes through ducting in the crawl space beneath the house and loses heat dramatically, but during the shoulder seasons at least it's fairly effective. From everything I've learned here and elsewhere, and it's been said in this thread before, what you want to do is move the air from low in the cooler spaces toward the room where the woodstove is located. We're still working on finding ways to do that better ourselves. Good luck! Rick

 

[savageactor7]

I have a fan on the stove QF 4300st but only use it when it get real cold...otherwise it drives you out of the living room. To move the heat through the far reaches of the house house we always have a ceiling fan on...those big blades move a lot of air quietly.