Lenny; With an 8" system in a greenhouse , I seem to average 100-120 at the hot end and 80-90 at the far end . If I burn hot all day I see 130-140 and 90-110 . In an insulated house it would be more.
For all your Montana Masonry Heater parts (also known as) Rocket Mass heater parts.
Visit me at
dragontechrmh.com Once you go brick you will never go back!