I see the City has a Temp occupancy Tax (TOT) of 10%  for renters less than 31 days...not sure if others have found these type of ordinances "writing on the wall" regarding a change in attitude towards rental properties.   

WE have a number of contractor friends & they are always at the mercy of their subs & temps but their reputation is what ultimately suffers. 

Me, I'd be temped to let my mother  take over, and she would go in a completely different direction.  

No mention of the STR in Paradise Valley, AZ used for shooting porn flicks or the gang shootouts in Phoenix, Scottsdale, Tempe & Mesa STRs?

an underground heat exchanger (constant temp underground) would be way too expensive to build and not even advisable in Astoria. gas is a much cheaper alternative to electric here in NYC.

you were in Oakland and the temps there are always  moderate.. being right on the bay..

Temp equipment like a dumpster or toilet or tools from Home Depot. 8.

He recommends installing a three way mixing valve and cranking the temp up to 150 to extend amount of hot water available.

That's pretty much it.Flip the emergency switch to on.Set the thermostat to a warm temp. 70-73F should be fine this time of year.Thermostat will send a signal to the unit to fire up.If nothing happens.

During the winter I used an IR thermometer on it and the others and there was no detectable temp difference inside.???