In the electrical trade the only time there is a reference to start and running amps is when dealing with motors. The running amps is always lower than the starting amps. A 78 amp electric furnace will take a 100 amp service for it to operate and be within the electrical code guide lines.
Minimal 100. Depends on load draw of home. Can be 200 amps or 400 amps as well.
Almost any average size home today will requre a 200 amp service panel.
Heck NO if it a gas unit or Uses Bunker C
The power required to run a basic computer will be 1.35 amps for startup and .7 to .9 amps continuous. The power requirements to run an 17" monitor will be 3.5 amps startup and 1.5 amps continuous.
22o voltage
It depends on the amperage's of the appliances. You should be able to draw, Amps = Watts/Volts, 2500/120 = 20.8 amps at 120 volts.
You should not run gas from the furnace to any appliances.
If your furnace is opperating correctly and the vent is in good opperating condition, You can run the furnace non stop forever.
It depends on the ambient temperature and the setting of the thermostat.
Not if the furnace exceeds 5000 watts.
None.