Wet1 said:
Do you really notice much of a difference with the blower on?
Yes, a measurable difference. I've done significant experimentation with blowers (for my setup) and there is a measurable difference in both stove top temperature and room temperature. I can literally prevent my stove from over-firing with a 200 cfm blower. This allows you to run with a higher air setting, burn more fuel quicker, and then extract that heat.
I'd say running my fan at roughly 80-100 cfm the stove runs about 100°F cooler on top at a given air setting and the room temperature goes up several degrees and it gets there quicker. Also, the heat disperses into the rooms further away from the stove much better - maybe as much as another 5 degrees.
From a cold stove start-up what I do is to get the firebox packed and when the temp hits 400 or so I engage the fan at 75-100% depending on how quick I want to heat up the room. Then I continue to run my stove at wide open air and let the temp climb to 600 (if I can get it there - tough to do with the blower on max). Then I can reload the box with another full charge of fuel to the top of the baffles and back off the air setting to whatever I like and back off the blower to the 25-50% range where it becomes very quiet and almost unnoticeable. I will turn it off completely if the room temp gets too high, but I prefer to keep it at 25% just to keep the circulation of the air into the room.
The blower allows you to extract more convective heat from your stove. I've seen #'s ranging from 15-30% and that seems plausible based on my measurements. In my hearth mount case where the stove is partially in the fireplace, the blower makes a big difference. If you have a stove smack in the middle of the room with no obstructions where you already get good natural convection, it isn't going to be nearly as beneficial. We are really just blowing air over a heatsink, but it works remarkably well.