I love that idea... of keeping a journal of wood use and the temp outside. I think i may begin that idea as well... maybe in a low grade way. Like in the morning when i first load it at 6:00 am... I will write down how many pieces of wood i used.. and the temp outside. Then when i get home at night.. again.. how many pieces of wood i use before i go to bed and the temp outside. It may give me some data at least to use for next year in calculating how much wood i will need. As of right now.. I have used the Tarm with no storage and am very happy with house temp. an hot water. keeping house at 70 when we are home ( even night) and 66 when we are all gone for day. I load 3 times a day. 6am,5pm,10pm.... varying size of load to temp. I have used aprox a third of a cord in 25 days. I am estimating higher for the next 2 months. SO even with high estimate... I could be looking at 20 days burning a half cord? This brings me 120 more days of heat using 3 cord? Not bad. I could even handle burning a little more if need be. I am hopeful for this estimate. I have plenty of wood stored... way plenty... which is fine.. at this rate.. I have the next 2 years stacked outside.