Simple heat transfer equation is defined as:
q = k A dT / s
where
A = heat transfer area (m2, ft2)
k = thermal conductivity of the material (W/m.K or W/m °C, Btu/(hr °F ft2/ft))
dT = temperature difference across the material (K or C, F)
s = material thickness (m, ft)
Basically every material has a specific thermal conductivity and the greater the temperature difference between the two sides of the material the faster it will conduct heat from one surface to the other. That being said it completely depends on how much heat your blower is able to pull off the surface of the stove and change the temperature difference between the firebox and the outside surface of the stove. In some stove designs it may be very negligable however others such as the Dutchwest which I am familiar with it was very noticeable. Allright now who on hearth.com is up for taking all the IR measurements so we can get some hard numbers to throw in this equation (Not It)

After sayin all that I thought I would add that I don't always run my blower. In fact about the only time it runs is when it falls below 30 outside at which point it runs full time. I think the next thing we should discuss is whether it is cost effective to run the blower or not with the extra electricity costs :lol: