Open chases in attic floors cause a lot of heat loss in the winter to the attic which can cause ice dams in the winter. This homeowner has a lot of humidity and heat on the upper floor. As hot moves to cold the heat moves down the upper floor from the attic through these big openings. Imagine how much money you lose every year out of these big penetrations in the attic floor. This will be properly sealed off with sheet metal and foam max from Dr. Energy and sealed with fire caulk so its safe to be around the furnace flue pipe.