Units are sealed and really don't take up that much space (see picture). I've got my in the mechanical room crammed between the furnace and hot water tank. The mechanical room is convenient as easy access to a supply and drain (then really good at least for me as my mechanical room seconds as a my basement fish room).
See no reason couldn't go in garage if it wouldn't freeze.
With the kit your looking at, it's basically 3 lines; supply (would be the "
Self Piercing Saddle Valve Water Supply Connection" usually for tapping into a copper supply line) waste ("Drain Connection" to join to a waste line), then the output to a container or bladder. If your output goes to a container for storage it's handy to put it through a float valve (so the container doesn't overfill) then also good to have the "AUTO SHUT-OFF" since the unit would continue to waste water until manually shut off.
Ratio is around 1:4 (1g filtered to 4g waste)
