I don't understand. How close will the vent be to the water pipes? Can you provide some more details?

I cannot imagine that having even a duct open to the outside would affect adjacent water pipes if proper insulation is used. And the duct will not be open, it will have a damper at the fan and at the exit to the house.

? Never heard of this constraint, and I live in Maine. Let us know what you find out.

A little more detail, as requested. The water pipes are copper supply in an exterior wall. They would be pretty close to the water pipes, I'm not sure exactly how close, but either within the same between beam span or one over.

The installer, who I credit for not wanting to leave me with a difficult situation, was talking about "radiant cold" which I'm pretty sure isn't how cold operates... but I see his point. Just surprised that insulating the pipes and duct work wouldn't manage things.

The hood itself is a pretty heavy duty one, not sure of the cfm, but it is a 36 inch maytag a going over a 30 inch gas stove. Yes, odd, but it takes care of a spacing issue. The vent that comes out is rectangular, but can be converted to 6 inch round.

The home is vinyl sided, with I think some of that styro type exterior cladding behind it. The interior wall is plaster lathe. it is on the west side of the the house.

Is there no insulation in the wall?

Would it be possible to move the outlet vent to one side, so there is a stud separating the vent from the plumbing?

I live in North Dakota, and understand a little about cold weather. If your pipes aren't freezing in the wall now, I really don't see them freezing next to a range hood vent. We run our plumbing lines in through the floor instead of the ceiling, and not on exterior walls.

robbcs - you are right that pipes in an exterior wall aren't really the state of the art in construction these days! But its what we've got. The house was built in the 1930s.

Weedmeister - absolutely no insulation in the wall...

Like all of you, I a surprised that the addition of a vent wrapped in insulation and a well sealed outlet would cause such problems.

Is there anyone out there who has actually done this? Run a stove vent through an exterior wall that has no insulation and copper supply pipes?

Can you add insulation to that wall, or at least around the plumbing?

You might wish to cross post this problem on GW appliance forum too.

Could you add injectable foam insulation to the wall if enough room?

We're in MN in a hundred year old house we've lived in for nearly 30 years. We haven't done what you are contemplating, but I can see what the guy may be referring to. If you introduce another opening into the wall, even if you wrap those pipes in insulation, they would still be exposed to that very cold air since the rest of your wall space is basically an uninsulated void that could reach potentially be very cold IF an extreme cold snap came. Our kitchen plumbing is copper and on an exterior wall, but when we first moved in many years ago we insulated all of the walls in the house. Nonetheless, when we are anticipating really cold weather like twenty below, we open the doors in the sink cabinet so the warmer room air will get into that cabinet space and keep things a bit warmer than if the doors were closed. The problem comes if the water is not flowing through the pipes (think being on vacation). Some people around here if super cold weather is anticipated might also leave their faucet running at a slow rate all night to keep things moving. It is not as much a problem during the day because the sink would be constantly used during normal activities.