I'm answering your second question first, because I want to get a little more input from Norwegians on the first.
Norwegians don't have central heating like we do in the States (of course, I am generalizing...maybe some do?). The family that I live with have a few different things they use to heat the house. First of all, the first story has heated floors. I believe it's only the first floor, since the heat will rise and warm the second level.
These are the two types of floors they have on the first level. The hallway/tv room and entryway are all heated from underneath. I'm guessing this is electric, but I'm not sure. The floors of the bathrooms are also heated.
The heat is controlled by a temperature gauge on the bathroom wall, and on and off switch.
Next, they have two ovens or fireplaces. These are the main source of heat in the house. One upstairs and one downstairs. You have to build a fire with wood and things to get them started. This one is upstairs:
And this one is downstairs:
Lastly, they have small heaters--two in the new part of the house that is not done--including my bedroom.
These are just plugged into the wall.
That's it. I asked the mom how much their heating bill was for the month...and she didn't know what it was just for heating--but for all electricity purposes (lights, heat, hot water, laundry, etc.) it is 1500 kroner per month, which is about $250.
For the most part, it always feels warm in the house. I guess the time when it might be a little cold is in the morning when everyone first wakes up. We usually eat breakfast sitting by the fire! (Meaning the kitchen table is right next to the upstairs fireplace/oven.) I also don't have heat in my bathroom yet, so it gets pretty chilly in there!! (I do have hot water though.)
I hope this answers all your questions! Let me know if you have more!