Installing an Inline Bathroom Ventilation System
I have a ranch-style house I am remodeling and thinking about installing an inline blower to vent the bathrooms, but I still have a couple of questions.
Is it preferred to vent through the roof or through the gable end?
Is it practical to install a trunk and branch style system with switch-controlled electronic dampers at each bathroom or is there a better approach?
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Check out the Aldes-USA site. They have a multi port system that you describe. What do you mean by practical? I am looking at the Aldes ZRT to bring into a trunk that goes into a heat pump ERV. My design goal is to reduce the number of penetrations through the envelope and control humidity. I am also trying to minimize the number of devices to minimize overall maintenance. So think through how you will replace a fan motor.
In terms of exhaust placement, think of condensation occurring. How will condensate drain from the trunk and what is down hill? The exhaust line should have a small slope so it drains to the outside, if condensation is going to occur. It should also be well sealed to prevent moisture going into the attic, it should flow outside.
Another consideration is to keep the duct as short as possible.
Are you willing to share more information on your ventilation setup? I only know of a couple heat pump ERVs (Minotair or CERV2) and I'm curious how you're setting up the ducting / zoning / controls to have bathroom exhausts work, as I know these units have both ventilation and recirculation modes that they switch between.
My understanding is that this is kind of a six of one, half dozen of another situation. If you vent thru the roof, you have a penetration of the roof membrane, but you also ensure that all vapor truly exits the home. If you vent on the gable end, you may have humid air from the duct rise get captured under the gable and potentially lead to rot.