I have my Olympic wood burning fireplace insert pulled out in order to clean the fireplace flue. This stove was in the house when we bought it and we have used it for over twenty years. This is the first time I have had it out or cleaned the flue, as it weighs a couple hundred pounds and is a monster to handle. I set up a little photo gallery so you can see what I am talking about in this post. My photos are located at http://gallery.me.com/rbarline#100056 if you want to take a quick look.

I need some advice on a few questions regarding problems with down drafting, setting up external air intake for more efficient heating, and the need for a flue liner for safety.

Question 1: What causes smoke to downdraft in high winds? This usually happens when we are just starting the fire (so the flue is still cold and the fire is smokey). My wife thinks it indicates a defect in the seal between the Olympic and the fireplace, but upon inspection there is no space between the fiberglass insulation lining the fireplace (which is a heatilator by the way) and the insert, so I'm not buying it. My theory is that when the wind blows it draws air out of the house through the walls and causes a negative pressure inside the house. This theory is supported by the fact that the problem diminishes as the fire gets hotter (and the flue warms up creating more upward convection pressure to counter the negative pressure). So, am I right about this? If so, this brings me to my next question:

Question 2: What are the pros/cons of installing a system of outside air intake? My plan would be to use the existing ash clean out (which has a door on the floor of the fireplace and one outside at the base of the chimney). I can visualize a sheet metal duct that would be designed to bring air out to the front of the unit so that it would be available for intake to the stove, although there is no "intake" per se. My thinking is that not only would this displace warmed combustion air with cold, but would also allow an alternate source of outside air when the wind blows and creates negative pressure in the house (see question 1).

Question 3: In my situation, where the masonry chimney is on the exterior of the house (and assuming the ceramic flue liner is in good condition), is there a compelling need to add a metal flue liner? I understand that there is one wood wall in contact with the chimney, but it's a short chimney (see photos) so that risk is fairly minimal. Would adding a liner provide any other advantages beyond minimizing the risk of a fire in the attic? For example, would a liner help with questions 1 or 2?

Thanks for any assistance.