For smoking temperatures, for pork shoulders, and beef brisket, ranges like 225-250 seem to be mentioned often. But I'm new at this, those may not be ideal temperatures, or the typical suggested temperatures that you'd often want to reach.
In terms of heater wattage, I can't tell you how much power you'll *need*. But I compared the volume and heater power of a few electric smokers, if it's of use to you.
I used the outside dimensions of my
Masterbuilt 30" (20070910), and a
Masterbuilt 40" (20070311), using specs from their website. I considered that as the total volume of the smoker, pretending that that entire volume is heated (in reality, the actual heated air volume would be less). Note that these smokers go up to 275F, and are insulated.
The 30" smoker has a total volume of 7.8 cubic feet, and an 800W heater. That is 102 watts per cubic foot of volume (W/ft^3).
The 40" smoker has a total volume of 11.9 cubic feet, and a 1200W heater. That is 101 W/ft^3.
By contrast, your dimensions equate to 52.8 cubic feet (as BBQWillie said). If you were using a 2000W heater, that would be only 38 W/ft^3. If you wanted 100W/ft^3, you'd need about 5250W. Which would require 3 separate 110V circuits, each almost fully loaded.
Keep in mind a few points:
- The
Masterbuilt calculations use the total volume of the box. Subtracting wall thicknesses, etc, the actual volume of air they're heating is less. So their effective W/ft^3 is actually a little higher than what I show above.
- Those units are insulated, so that reduces the required W/ft^3. If your box was not insulated, you would likely need additional power, vs what they have.
- With that said, they are also designed for the ability to reach/maintain 275F, hopefully even in cool conditions. If you only needed, say, 150F, in warm weather, you could get away with less power. But insulating your box would seem quite important, as you will have much less power density available, if running on a single 110V circuit.
You mentioned plywood, so this next thought might be very unsafe. But if, hypothetically, your box was all-metal, and had no risk of burning, you might be able to "cheat". A small propane burner, for instance, running constantly, could provide a boost in heat (effectively more watts). And an electric heater element, controlled by a thermostat or similar, could provide your temperature control. You'd always have some heat being added, by the propane burner, but the electric heater would provide the rest of the power, and would help regulate the temperature.
That could reduce your load on the electrical service, while still allowing higher temperatures. Or, if you could supply 220V, you could use something like a roughly 5000W oven heater.
How much stuff are you looking to smoke at once? That is a really big volume, the size will make some things tougher for you, like by restricting the max temperature you can reach.
