I have been looking around at used fireplace inserts within my budget for a while now and came upon a Regency I2100M for sale for $600. It was manufactured in 2000, but was VERY lightly used as a backup source of heat and is in excellent condition. I can't find any specifications on it, but the owner says it wasn't EPA certified, but it is the same thing as an I 2400, just an older model. I was able to photograph and measure an I2400 at a local dealer, and there are some very minor differences, but nothing that leads me to believe that this is anything but a sweet deal. Can anyone confirm that the I2100M is just an older model of the I2400? If the heat output is almost identical, then I think I better act fast before it is gone. Any thoughts?