In the South, humidity with AC that hasn’t been used in a while can cause humidity in the walls, in the Northeast Pipes can freeze if the house sat vacant through the winter, in Florida they get wind driven rain which is bad for roofs.

He did not desire the humidity in the garage (laundry hookups are in the garage in this SFH). 

If you don't like traffic or rain or bugs or humidity, central WA would be my choice. 

But mainland US.One thing CA does not have though is HUMIDITY  generally speaking.. 

@Alyssa Lebetsamer there is technically mold spores at some level many places that are damp or humid.

That is bad for the house (humidity) and bad for the A/C unit to run that hard.Was it worth it from a cost standpoint...no.  

Same dumb laws, poor returns, but with more humidity.

I would say no for 2 reasons:1) she might want to make it into a grow room, which will wreck your unit - the humidity and potential water on the floor, plus the smell, etc., will possibly do major damage; and2) tenants who start wanting to change things are never-ending high maintenance tenants and you're better if they leave. 

I've lived in other places and there are so many things about living in CA that are unique and priceless, like low humidity and pretty much zero bug issues. 

High humidity will challenge even the best system, even if it's matched to the house.