This is pretty much a "do the math" deal. To convert BTUs into watt-hrs you multiply by 0.2931. So that 5119 BTU unit is drawing about 1.5 kw-hr worth of electricty. Multiply that times your electric rate to get your actual cost. 8 cents would then equate to a rate of about 5.3 cents per kw-hr, and that's pretty low by today's standards. But a room heater drawing 1,500 watts is pretty typical, and I bet that's exactly what this one is.
Now you need to determine whether or not a 1,500 watt heater is enough to heat a room and the answer is "it depends". That might be enough to heat an average size room if the ambient temp. is modest, low drafts, good insulation, etc. How heat is delivered can make a big difference also. Radiant heat might be most effective, because with that method you are heating objects instead of the air mass. But the objects need to be fairly close to the heat source to feel comfortable. Forced air or convective heat often feels better, but that means heating the whole space and it might take a higher power input to do that to the same effective temp. 1500 watts is about the upper limit for a space heater that plugs into a standard 120 volt wall outlet. That translates to 12.5 amps and a household circuit on a standard 20-amp breaker can only sustain max. 16 amps continuously. You probably have other items plugged into that same circuit as well.
I can't see where the Heat Surge is any better than other space heaters, and that's not to knock the Amish, a group I respect in many ways. The units are expensive ($250 ea.?) and you're paying a good chunk of that money for the fine woods and craftsmanship and the "fireplace" aura. But in terms of heating efficiency there would be better options IMHO...
AFTERTHOUGHT: I just saw a 2-page ad from a Sunday supplement. I got a real chuckle of the image of several of these units loaded into an Amish horse-drawn wagon, like they're being hauled home. You can bet the Amish aren't buying these! Most don't have electricity, at least not in the main house (in the milkhouse, maybe), and to be sure they always do their homework before parting with any of their hard-earned $$...!
PPS - $249 is just for the heating unit. With the mantle must cost more...