For a rental house the issue is usually initial cost. Since a hot water boiler with one or more circulators is probably the best option you only need to get prices for under floor and baseboard distribution systems.

Absolutely NOT! You want a call in the middle of the night that there is water leaking from the floor? You'd probably find out that they nailed a doorstop through the tubing or had an unauthorized pet have repeated accidents and were trying to replace the floor boards when they punctured the tubing.

Do not waste expensive state of the art technology on vandals that barely pay you a monthly stipend to not sleep in the streets. They WILL find a way to damage it, even if you think it's not possible.

How did the dwelling come to have no comfort heating appliance, which has been required by CA. building code, as long as I've been around?
Before your "carpenters " close the walls and ceilings up, have gas line run for a wall heater, which the plumber can also install and vent.

The previous tenant removed the baseboard heaters that existed in the house originally. He also took all the appliances, the copper pea traps out of the sinks, and some 220 wiring cable from the unfinished laundry room (the electrician was floored, he said the guy had to be pretty ballsy to do it.)

BTW, my carpenters have 60+ combined years experience building houses, they know what they are doing and don't deserve the quotations.

I'm also a "carpenter" with 40+yrs. experience, and put the bags on every day.
I also accomplish both elec. and plumbing, and would have advised you of the pros and cons of both elec. and water driven radiant heat systems as well as alternative systems that would fit easily into your present fuel source systems, obtained estimates for what you select, or both.

And by the way, in those 40-yrs. I've had one warranty call back and that was for painting, thats for the ".

As a courtesy to the other members you two should move your trivial spat to the Conversations section.

Renovator8, instead perhaps you, now having the knowledge that the OP resides in a mild climate zone, and perhaps the subject dwelling which was heated by elec. baseboard devise, might entertain some addition constructive advice.

However let me provide you with some insight for the area.
In the 60's and 70's during the condominium boom some of the multi unit developments employed a dislocated boiler system to provide hot water used in heating and general use. Since the rate of usage was not individually metered, the cost was mutually shared in the form of the association dues.

The prevalent system is the individual 40gal hot water heater where water and fuel sources are also individually metered.

The latter, while not predominantly used in single family, is.

Boiler systems are an exception,

You should be talking to the OP. I rarely read your comments.