I'm not sure which section to put this in so here goes...
I'll be remodeling our kitchen in the near future and I've a quandry - there is an existing ducted exhaust in the kitchen but I'm uncertain whether to tie into it or just install a new run straight through the roof. House is ranch with insulated crawlspace attic and range will be on an interior wall. Either way I'll have to get into the attic (respirator.tyvek suit). I'm wondering with a straight vertical run, what kind of damper need to be installed in order to keep heat from escaping all the time.
The existing duct ran off a ceiling fan which, as you can imagine, was worth next to nothing if it ever worked. As we never tried to use the current fan, I don't know if the ductwork is clear or not.
Also, if I'm going to go through the roof, I'll need to get cracking since it's mid-October and will be getting colder soon here in upstate NY.