Having decided it’s best to maximise the usable space (and thus, not build a typical window frame for the vent), the rest of it is easy planning.
Last night I built a metal bending jig with some bolts, wingnuts, and some punched flat steel bar. I then used it to bend some pieces of metal flashing to make a shroud for the vent hole. Pics:
These are currently just pushed into place, which is why they look like they don’t fit so well. When it comes time to mount them, I’ll use some small screws and silicone, probably. That screw you see is the hanger used to mount the water heater.
The purpose of the metal flashing is twofold: first, a shroud to handle the potential heat output from the water heater, and direct it efficiently out the side of the tiny house. Second, as a magnetic attachment for the rest of the vent. Once the heater is mounted, I’ll build the second half of the vent, which will be like those plastic register deflectors (but made of metal), with magnetic strips to attach it to the water heater and vent shroud.
I didn’t cover that whole gap in flashing, since the far left side will be occupied by the exhaust fan (for the shower), and there’ll be a metal wall just on the side of it anyways. I’m planning on mounting the fan ‘vertically’, i’ll need to chisel out about 1/8″ top and bottom for the feet, and will wrap the feet in felt for vibration dampening before screwing it down. That’ll be covered in another post – I can’t mount the fan until I’ve got the exterior siding for that section cut.
Here’s a close-up of the new filament-style LED bulb I bought: