Put this load in last night 2 year old oak and beach at 1130 and this morning its 830 and i still have 79 in basement and 70 first floor. and its 8 degrees out. stove top still at 350 with fan on low. turn t stat all the way up when woke up at 7 and still get a ton of heat out of the load. just amazes me that almost 10 hours later the amount of heat out of this thing.