We use two electric heaters. I think they are ceramic type and are rated at 1500 watts. I am not sure how that equates to BTUs. They are zero clearance. No part is hot. Forced air and you wold have to hold your hand on the oulet for a while to get burned. One big problem with the heaters is there operating cost. The electric bill was around $400 a month. It got as cold as the mid 40's several times this past winter. Usually happens when have a cold night (low 20's) and then the sun doesn't come out the next day and it stays below 40. The heaters run all day and the temperature never recovers.
There is a fireplace with an insert. It never heated the room it is in very well and burned a lot wood ever day. Had to feed it a couple or more times during the night the temperature would get low enough for the blower to shut down. It uses a catalitic converter that seemed to wear out in one or two seasons. It is fairly expensive to replace. We only burned seasoned oak.
BTW, I don't trust vry much on YouTube useless I find a lot of other sites and/or books that agree. I have found that you can watch 6 videos on the same subject and find at least twice that many descrepences. Most are small but some are huge.
Richard