I purchased and Enviro Empress that has a 3 inch vent outlet. My plan is to use a 3 to 4" adapter then go a 4" direct horizontal vent. There are two reasons for doing this: 1) The place where I bought the stove threw in some 4" pipe and termination for no charge. (new Simpson Dura Vent) 2) I want to have the option to add exterior vertical in the future if I have problems with venting or soot build-up on the house this year. So, my question is: Is there a difference in how a 4" horizontal set up with vent compared to a 3"? Any warnings or potential pitfalls that I should be aware of. I am new to this forum, but enjoy it a lot and did search as much as possible on the forum and through google before asking this question, but I do apologize if it has already been answered somewhere.