Is running the fan on a small insert less than full out a waste of wood?
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michaelryba
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For me, the fire is supposed to a source of comfort, not noise. So I don't run the fan on high too much. But remember, there's only so much heat to be harvested from the sides/top of your firebox. For a given fire, a low fan speed will warm the air from say 70 to 100 F. A high fan speed will warm the air from say 70 to 85 F--but at twice the velocity. Not much of a net gain if you ask me.
The only way to get a high velocity of hot air is to load your firebox up and run it hot. Obviously, this uses a lot of wood--not exactly your goal here.
The only way to get a high velocity of hot air is to load your firebox up and run it hot. Obviously, this uses a lot of wood--not exactly your goal here.
IMHO, max fan speed is maximum efficiency for a couple of reasons:
1) The actual 'firebox' in modern wood stoves is sufficiently insulated from the steel shell so blowing on the steel shell does not create any less efficient burn. IE - secondary combustion will continue regardless of what blower speed you use. If this is a special case and you notice a drop in secondary combustion or a lot of smoke out the flue when the fans are run, you may want to stay on low speed, but I'm guessing that is not the case
2) Extracting maximum heat from the stove requires maximum air flow. The greatest temperature difference will make the greatest heat flow, and the way to get the maximum temperature difference is with lots of air. True, low speed may give 100 degree air and high gives 80, but if you work out the CFM, there should be slightly more btu's in the larger volume of cooler air.
3) The larger air flow should mean less of a 'hot spot' around the stove. The hot area around the stove looses heat exponentially faster than a cooler zone. This heat loss would be minimized if your stove in on all interior walls, with heated space above and (ideally) below as well, but if the stove room has exterior walls and/or especially attic/unheated space above, the rising warm air can loose a relatively large amount of heat. If you minimize the air temp with the blower, heat loss is minimized as well.
On the down side, more airflow usually means more noise and if you are in the breeze, you can feel cooler and stoke the fire hotter which may eliminate any savings from the increased efficiency in the first place.
1) The actual 'firebox' in modern wood stoves is sufficiently insulated from the steel shell so blowing on the steel shell does not create any less efficient burn. IE - secondary combustion will continue regardless of what blower speed you use. If this is a special case and you notice a drop in secondary combustion or a lot of smoke out the flue when the fans are run, you may want to stay on low speed, but I'm guessing that is not the case
2) Extracting maximum heat from the stove requires maximum air flow. The greatest temperature difference will make the greatest heat flow, and the way to get the maximum temperature difference is with lots of air. True, low speed may give 100 degree air and high gives 80, but if you work out the CFM, there should be slightly more btu's in the larger volume of cooler air.
3) The larger air flow should mean less of a 'hot spot' around the stove. The hot area around the stove looses heat exponentially faster than a cooler zone. This heat loss would be minimized if your stove in on all interior walls, with heated space above and (ideally) below as well, but if the stove room has exterior walls and/or especially attic/unheated space above, the rising warm air can loose a relatively large amount of heat. If you minimize the air temp with the blower, heat loss is minimized as well.
On the down side, more airflow usually means more noise and if you are in the breeze, you can feel cooler and stoke the fire hotter which may eliminate any savings from the increased efficiency in the first place.
savageactor7
Minister of Fire
As long as the fan is pushing out heat it's working.
Or are you asking does the wood burn faster with the fan on? <---- No the fan is just moving air captured around the outer shell of the stove and doesn't effect the primary air that controls burning.
Next time the stove goes cold try taking the blower off, host it off with compressed air, spray the ends with WD40. Maybe that'll help quiet it down.
Or are you asking does the wood burn faster with the fan on? <---- No the fan is just moving air captured around the outer shell of the stove and doesn't effect the primary air that controls burning.
Next time the stove goes cold try taking the blower off, host it off with compressed air, spray the ends with WD40. Maybe that'll help quiet it down.
I run the fan on high when warming up the house and on low once it's warm. I have the heat set at 60 while I am at work - once it's 70 in the house - the fan goes low.
Why would you be wasting wood? If the fan is on high (keeping your temps where they need to be) - if would become a suana in my house (1200 sq ft). When the fan is on high you just burn the wood faster (leaving the air open more) getting more heat faster. Once the house is up to temp you close the air more and the fan on low - so it burns longer.
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