If you need to have batteries it makes a solar system MUCH less cost effective.

Now that I use 10 year batteries in smoke detectors, it's hard to be sneaky about doing an inspection.

I use keyless locks (push button code) from homedepot they're about $100 and really easy to install and reset, battery lasts a very long time as well I would definitely use them for a vacation rental.

How also, if you store energy in batteries, sell it back to the utility company?

From my screening I already knew about her arrest for battery so I decided to be cautious and humor her.

I've seen websites in Minnesota that say you cannot charge rents against the damage deposit.  

The owner would have to buy for almost nothing and charge rents as if it were the Hilton.

Nothing substitutes for a good battery of questions and following up with references, but do you have any specific advice?

You plug in the receiver into an outlet where you want to be able to hear it, then put the battery operated button outside.

I save $$$ big $$$ every year because my lead tech takes the time to try to walk the resident/tenant through the problem they are having and resolve via phone if possible.My favorite hero call every time, is when it is 20 below and tenant calls with a furnace out issue, turns out it is simply the batteries in the thermostat, many people do not know that the thermostat in nearly all cases (except for a modern nest) are not direct connect/direct wire and are powered via battery.