It depends on the price of pellets and natural gas in your area. In general, pellet stoves are a little more expensive to operate than natural gas, but the cost of pellets varies widely depending on the region. So it's important to do your research before you decide which is cheaper for you.

It is cheaper to run a pellet stove. Pellet stoves are around 80% efficient, while natural gas furnaces are only around 60% efficient.