In a house I had many years ago, with a Natural Gas boiler, I had plastic on the cheap windows to cut down infiltration. When the boiler was not running, the plastic [just plastic sheet, not the good mylar available now] would have bags and sags... when the boiler fired up, the pull or draft on the house was enough that the plastic would puff out into the room, the wrinkles and sags stretched taught. They looked like clear plastic pillows..
I installed a 4" dryer vent from outside to the base of the boiler.. nothing fancy, a screen on the outside to keep critters out, and just set the end of the 4" duct on the floor at the base of the boiler. The difference was immediate.. the plastic sheet on the windows stayed wrinkled and baggy even when the boiler was running.. The only time the plastic would puff out smooth was with a very strong wind... the house had a central chimney about 30' high..
In my current house, with my coal boiler outside in a remote building,, I don't have very much infiltration in my house.. there is no active chimney most of the time.. So I notice a reduction in wind-leaks and cold air infiltration..
I would highly recommend an outside air source for any in home burning appliance.. Coal, NG, propane or oil.
If you attach the outside air duct to the inlet of the COMBUSTION fan,, NOT the air distribution fan, then the stove will not be 'heating' the air, the fire will be consuming the air... The distribution fan inlet will be pulling air from the room, not from the outside air duct.
I recommend a duct over the inlet of the air distribution fan as well, and have this be part of a cold air return system.. most distribution fans are near the floor, and therfore pull in cold air off the floor, this is especially a problem with a basement instalation.. the air on the basement floor is the coldest air in the house.. since you are trying to heat the living portion of the house,, pull air to the inlet of the stove's distribution fans from a warm part of the house, this re-heated air will just get that much hotter, providing more heat to the living space.. This creates a circulation loop from the stoves heated air outlet to the heated portion of the house, and returning back to the distribution fan. This ducting helps to make the stove more like a furnace..