This is just a short clip I recorded with my phone of the fire burning in the Osburn 2400 fireplace insert we installed last spring. It measured about 550 degrees Fahrenheit on the top plate. I didn’t think to measure the internal temperature at the time but given that it measures about 350 when it’s about 650 on the inside, I would guess it was roughly 850 degrees inside.
We’re really happy with this fireplace insert. It burns very efficiently and hot enough to burn any creosote buildup off the fire bricks on the inside. It easily heats an 1800 square foot area (the basement) and with the help of a fan, can push some of that heat upstairs.
I doubt it would keep the entire house warm on sub-freezing days but so far without using the heat pump it keeps the upstairs above about 65.