Alternatives to bathroom exhaust fan. Install only one 1 Outlet fan With the double air flow capacity the single fan in alternative 1 installation at same height on a same wall. And can be done with an appropriate fan mounted outside or with whats called an inline. The first way would be to purchase a dehumidifier for your bathroom. A ceiling fan along with open windows is best to ventilate a bathroom without using an exhaust fan. Plus the steam will be good for the heater dried air of the house. The moisture dispersed throughout the house is hardly noticeable and actually a benefit in the dry winter months.
Ducting Air Circulation and Ventilation Systems – Alternative to bathroom exhaust fan. This versatile bathroom exhaust fan is perfect for rooms of multiple sizes thanks to the Pick-a-Flow Speed Selector that adjusts fan operation between 50 80 or 110 CFM cubic feet per minute. Dont foam over your exhaust fan. I did install a nice quiet energy star fan on a timer but never use it. Removing the fans I see there are ducts but cannot see where the duct leads to. Open a window if it has one leave the bathroom door open use a dehumidifier they do make small counterpoint ones but they arent supper effective use an after shower spray there are waterproof sprays that resist mold and mildew but you have to respray every week. If youre interested Duraflo makes a soffit termination fitting for bath exhaust fans.
The excess moisture and stale air can be passed directly outside the house or vented into the homes central ductwork to be carried outside. Your plan A two bends and out the gable end is fine as an alternative. Generally thats via a roof vent.
This is a general guide to the majority of exhaust fans. Go ahead and foam over the ductwork. A ceiling fan or a pedestal fan. No matter the location of the bathroom you can vent the exhaust fan through the wall.