Don't forget the $10,000 in controls to manage all the zones and run the variable speed pumps. And an electrician running all the Tstat wires.
Not talking adding extra zones or controls.
Just that if there were already multiple loops,
and the loops were per-floor,
then maybe set the upper floor circulators'
giggle switches to LO,
because heat rises and the upstairs loops don't need
the same volume circulating as the downstairs.
Good friends/former colleagues were typical skinflint
MIT undergrads in the 60's, renting normal apartments in Cambridge.
Heat was included in the rent,
but the apartment's thermostat was in a locked box,
and the thermostat was set to "cryogenic".
Being MIT students, they solved the problem:
whenever they felt chilled in the winter,
they just sat an ice pack on the thermostat.
Viola! Toasty warm!
Whenever the landlord snooped around,
they'd just toss the ice pack back in the freezer,
and watch him puzzle over how the apartment was
like a sauna, but the thermostat was bottomed out
and there was no sign of the lock being picked.
but either way, still a good idea.
(If it was hot water, which we are told it ain't - it's steam).