I fixed a kitchen fan exhausting to the outside (yes, always smooth metal - never corrugated). I found that there were very small areas in the fan housing ((that faces the top of the stove) that were not sealing at all ..... since they just wanted it fixed without having to by a new fan I simply used some sticky (back pressure it is called) one side aluminum tape and put small bits around the small holes that were allowing air to be pushed back towards the stove. The sticky aluminum tape did a great job - I didn't stop until there until all the leaks were plugged. It was leaking just about everywhere. I was tempted to get a caulking gun out! She was happy, I was happy...... on another note...many homes do not have air coming into the house! With new high efficiency furnaces (gas) the installers have used the hole at the top of basement foundations to install the 2 furnace vent and intake pipes. Now that they have sealed off that former fresh air vent...many homes no longer have fresh air coming into their home..... no air coming in....no air going out. It was a townhouse and the refused my request to have fresh air enter the home.......?really?.... so I put a covered and filtered vent over a small basement window (all metal with a heavy metal screen to stop creatures as well. I found just having a 2 inch or so opening allowed plenty of air into the house. It was a simple fix.....bit cool in the winter... but with a filter it was actually one step up from the old 4 inch circular hole in the upper foundation.

Thanks for your reply Julie, My range will be located on an interior wall. Venting to an exterior wall, while not impossible, would be difficult, particularly given the low rustic wood beam ceiling in the kitchen. I only have enough room for about 25" of hood and duct to the ceiling, so just making that turn with 10" round duct to vent sideways would take up most of that. I have to believe people have roof-mounted blower systems in snowy areas of the Country???? I can't seem to find information about this on the hood or ventilation manufacturer websites. Has anyone had experience with this?

Here in the Denver area our temps have been colder than usual but overall snow totals are below normal (single digits daytime and negative temps at night). The mountains are getting amazing snow totals and it seems I-70 shuts down for at least a few hours once a week due to weather conditions. We do have quite a bit of snow on the ground now, but our temps are finally up in the 40's today and lots of sunshine so snow will melt fast. They say we'll be in the high 50's, maybe even 60 by Sunday. To those in the midwest and northeast, this beautiful sunshine should be heading your way--I only hope and pray it doesn't cause flooding by melting your snowpack too fast. Although I love living where there 4 seasons (lived in LA many years ago and it just wasn't for us), I will be happy when my crocuses pop up through the lingering snow and show their lovely purple and lavendar faces.

Every case is different, and some routes will be less costly than others. There is nothing wrong with going out a side wall, so long as it doesn't dump cooking effluent onto an open window, a deck, or annoy the neighbors. I just wanted to raise the point that there can be more than one option for routing ducts. A roof penetration always has some risk of leaking. Ice dams are another possibility, but one which proper roofing should ameliorate. A very steep roof should tend to shed snow on its own. In some hip-roof ranches, for example, there is no path from the attic to the house side, as the roof edge and soffit is below the top of the wall of the floor below. Such structures are pretty much limited to roof exhausts. The Wolf, Abbaka, and similar designs are intended to be relatively low profile and not require a curb. The up and down blast blower configurations assume that a curb is used with its bottom sloped to match the roof. HVAC is a HVAC project, but the exhaust duct is not a very complex project if the only issue is connecting duct properly and integrating a cap into a roof properly. It is more of a roofing competence project that small builder and renovation craftsmen should be able to do. I can only wish you good luck in an education culture that depreciates trade-craft and promotes low-employment-demand college degrees for the sake of selling college degrees, even if the result is graduates lacking practical skills living in their parents' basements and owing a lot of money. kas