Radiant floor/ceiling

[Harold hydronicnetwork.net]

Radiant heat will be very comfortable the way you want to do it. A LOT of heat will be radiated downward, so some insulation will be required to keep from basement roast and the heated tubing will be apparent to the basement. Remember, it is RADIANT heat, so the heated floor of the upstairs will be the heated ceiling of the basement which radiates heat up and down. Get material quotes from your local suppliers.

Also look up the meaning of efficiently, whatever heat you put in will come out – that is HIGH efficiency. Effective is another word that means it will be do the amount you need, that depends upon how much insulation you have in the walls to keep heat inside the building.