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We did a gut rehab of the kitchen in our 1907 twin this summer (including new drywall over 3.5 inches of foam insulation, since the kitchen had always been cold). We also got a professional range, and a big DCS range hood to handle the air flow. The problem is that the “professional” installers put a cheesy set of aluminum louvers on the end of the 10 inch diameter duct leading from the hood through the outside wall; the louvers do very little to stop air flow even when closed. We now have cold breezes blowing through the kitchen, making a mockery of our insulation efforts. What’s the right way to close off the end of this duct?
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Don't know who made the louvered damper for your fan, but Dayton is a quality brand for these. You can obtain a 10x10 Dayton wall damper from Grainger.
*Motorized damper tied to the fan switch?
*Don't most venting systems have a back draft damper to overcome this?Ed. Williams
*i Don't most venting systems have a back draft damper to overcome this? Yes, but 10" directly through the wall (I usually use a remote ventilator) is unforgiving. It shouldn't be done that way - imagine you've just superinsulated your house and now you're going to cut a 10" diameter hole and tack tin over it. Not much different.Not to mention the termination kit for 10" duct mounted on the side of the house.Jeff
*How about having someone remove the hood and manufacture a guillotine-like sliding door behind it ?
*The large vents I use are essentially upgraded dryer vents on steroids. The exterior profile is smaller then you'd imagine, and painted they blend in reasonably well. These are wall, not roof vents.The flapper is spring-loaded, and also contains a thin foam strip on both the door and the body for a snug seal when closed.600 or 1200 CFM blows it open, but the spring slams it shut when the airflow stops.No real R-value to it...but it's the airflow that's the killer, and this door, coupled with the vents own doors, eliminates unwanted airflow.Have you called the installer/builder/manufacturer? What sez they?
*When installing these supposedly great and wonderful range hoods, I've seen where the wall is framed out an additional 2X4 behind the range to accommodate a rectangular stack which runs from the range hood using a boot and exhausts at floor level using another boot, duct, and exterior vent. That way no cold air runs up the stack and you still have a fully insulated wall in behind it.TDC
*Pat,Have you done much work with the exterior to seal the house. I've found with new and renos that if the house is sealed with new housewrap, windows, etc. the natural air flow or air change decreases. If you go an add a range hood (the worst culprit) it can depressurize your house significantly if you don't have any make up air. If you have a regular b-vent chimney (ie. furnace/water heater vented thru chimney) be careful that you don't cause combustion spillage or backdraft. I know in my part of the world...I am not allowed to depressurize my house more than 0.02 in.wg or 5 Pa if I have B-vent (gas company has the right to turn my gas off)... This can all be solved by getting rid of the b-vent and any other chimney (ie. fireplace) and going with a sealed combustion furnace and power vented water heater where you can vent out the sidewall of the house with regular abs or pvc pipe. Check with the mech. contractor.TDC
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We did a gut rehab of the kitchen in our 1907 twin this summer (including new drywall over 3.5 inches of foam insulation, since the kitchen had always been cold). We also got a professional range, and a big DCS range hood to handle the air flow. The problem is that the "professional" installers put a cheesy set of aluminum louvers on the end of the 10 inch diameter duct leading from the hood through the outside wall; the louvers do very little to stop air flow even when closed. We now have cold breezes blowing through the kitchen, making a mockery of our insulation efforts. What's the right way to close off the end of this duct?