Vented units tend to be more about ambiance than heat. Ventless units provide more heat, but also put things into the air that aren't so great to breath. I personally would suggest a vented gas stove. There are numerous models on the market that provide both ambiance and heat and which largely negate the drawbacks of both.

Kerosene heaters have caused more fires than CO deaths of course. Kerosene heaters were not that much of a threat in older homes that only had caulk in places to keep water out. Most people who used kerosene heaters when they were popular for home heating were used to alternative heating sources and made sure there was ventilation of some sort. You seem to want to go back to old days when things were more forgiving. Houses were not sealed up near like they are now. I am sure that ventless fireplaces are manufactured to compensate for tighter homes than back in the 80's but there are many different sealing techniques out there. The ventless fireplace you purchase might be fine in your home if all of the warnings and everything are followed. If you helped your friend put one in his home that has Tyvek and spray foam insulation with no CO detector he might be dead in a week. The warnings are out there.. homes are not the same now as they were back in the days before the big sealing and insulating push. Take an 80's kerosene heater and put it in a better sealed and insulated home and watch the CO detector go off. You know what I have had it with trying to tiptoe. I am sure the majority of ventless fireplaces are still designed for 'vented' homes. I am also sure there are some that are designed for very well sealed homes, you might have to add a power vent to change some of the air in the home. I know someone who has one in a newer home and I can smell it as soon as the door opens even if it hasn't been running for a couple hours. They are 'used to it'.. it feels nice, but it smells and does leave a smell. They are not totally happy with it and it will set off the CO detector if you sit the detector on the floor instead of 2' off the floor or whatever it is supposed to be at. Oh and this is an electric home other than the propane fireplace they had added, oh and no they do NOT sleep with it on as they do not trust it. I say go buy one, you will love it I am sure! I am sure it is all BS, I am sure it all is a bunch of people trying to naysay and scam others. They are so great that the only reason companies build vented models is for something to write off on taxes. Everyone in here is full of BS too. BTW I know of stories where there have been power outages due to storms with newer homes where people used a kerosene heater to keep warm and died from it and the heater was inspected and had no failure. The only failure was the house was TOO sealed up. OH this person I know is an assistant fire chief. Like anything else you will get what you pay for.. be it vented or unvented.. but with unvented you might 'pay for' what you get eternally. What am I talking about... I am full of BS. I wish you luck and hope you realize its not all a conspiracy theory.

"...the Northern region...." and "..cold winters...." are not very specific. To people in Florida, Virginia has cold winters. Additional information about climate and your gas and electric rates would be useful in advising you.

Maybe try the home decorating forum.