Ok guys brand new to the forum here but i have been lurking for months. We finally purchased our new (old) house which came with a wood stove area and also a heatilator fireplace. We have been heating with a huge nashua wood stove "NFP2" and it heats the house great! The only problem is that we have a pretty huge house and on the other side of the house its a good 5-10 degrees cooler. We have tried all types of fan set ups and different things and nothing has worked. Across the house though, there is a heatilator fire place. It sucks! my plan is to remove the glass and the doors and install a nashua insert. my question is how can i tell if i have a "masonary fireplace"? The heatilator vents into a clay tile chimny and below the fire place is a clean out the goes down into the basement. When i go into the basement and/or the attic it seems that its all cinder block from the basement all the way up into the attic. I saw a video of a guy on youtube installing an insert doing what i want to do. My only concern is that I dont know how to tell the difference between zero clearence and a normal fireplace. Any info would be greatly appreciated