I have a large home and no money (retired too soon, I guess).
Only 4 people in the house - 3 bedrooms in use, all on different floors.
Multiple furnaces involved. Hot air.

Propane. About 3 bucks a gallon (or so).
Tiered pricing on electricity - about 45 cents for the last kilowatt in the
month and about 15 cents for the first kilowatt (very hard to average as it
depends on many factors not the least of which is time-of-day use).

The question is whether I should buy at Costco 3 space heaters.
Or just use the hot air heat sparingly.

The thermostat setup is the old style, Honeywell, mercury.
It doesn't lend itself to timed automation.
I'm not asking about a timer anyway unless it's the obvious answer.

Just asking one basic question, where the answer can only be "in general".
o In general, is it cheaper to manually turn on and off the heater, or,
o Do space heaters have their place in this cost-conscious scenario?