Good for you. That is a nice stove. The long burn times will be experienced when the heating demands are lower. How long will depend on the heat losses of the house and the amount of sq ftg being heated, but greater than 12 hr burns for temps above 25F are realistic to expect. The 30 has the advantage of greater fuel capacity whose burn time is thermostatically regulated which means you can have a larger stove without overheating the space.I really like the Sirocco but my wife is skeptical of the long burn claims and not happy with the way it looks. From what I read it seems that the 30 would work as well as the 20 in our situation- do you agree?