my 2KW rund my fridge, my CPAP machine, a few lights, and can run the furnace (all it needs to do is open the gas valve - we have steam, so no pumps/fans)

That's all we NEED - that said, I'm thinking of putting in a 10-14KW whole house unit - we have NG to the house, and along with the portable as a 2nd line backup, I should be good. The 10-14Kw unit is more a "it's nice" than a "we need"