Yep, exhaust is vented straight out the security block window.
Not sure what you mean by problems with the air flow messing up the hvac in the house so I'll take a few stabs.
Relative to the environment, the fans produce negligible negative pressure in the room if that's what your curious of. One singular muffin fan I use is about 200cfm, so it's not going to suck the air out of the house, I plan on adding one more, and that should be plenty to take care of superglue fumes and epoxy smells with a better hood setup.
I don't have any HVAC vents running into this room, and I did that on purpose because I don't want any possible fume leakage through the HVAC system, so if that's what you're referring to, I wouldn't be sure, because I don't have a single intake or vent in that room. I doubt the fans would create enough flow to mess with the hvac in any-manner though. I was just concerned with cross-room contamination through the vents.
I use a little space heater when necessary, but it's been -20F outside and only 56F in the room, so need for a heater really.
As for fumes outside, not gonna lie, it's pretty obnoxious if you're standing right by the window / exhaust outlets. If you're blowing your exhaust out anywhere near a neighbor (like within 10ft), you're gonna be gassing your neighbors lol. If your exhaust is below any windows that will be opened in the future, make sure that window is closed before you turn on the fume extractor system.
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