Roof and attic insulation are key factors in controlling the heat load.Commercial HVAC sizing is based on that plus the addition of heat from air supplied from the outside to replace "stale" air indoors - local ordinances often require specified amounts of air replacement - in an occupied space and also from the number and activity of individuals expected to occupy that space.

@Jorge Leon State Farm seems to have some of the best rates this past 12 months in the 1-4 units space. 

Limited space for expansion ensures a housing shortage, driving up property values and rents.

As far as renting garages or extra space my insurance will not allow me to rent anything to a non-resident.

- Mark

Definitely second this - if you were thinking of taking 65% for yourself I would imagine you're pretty new to the STR management space (not a criticism, just an observation).

We can discuss it if you are looking for space for residential assisted living. 

Instant water heaters take up less space and come in electric or gas versions.

I marked location of retention wall in original picture.

This house is currently a 2/1 but with the additional 480 sqft of living space (main bath, dinning, walk-in closet).