Because my stove pipe was a similar distance to the top of my hot water storage, I used 1” ceramic insulation blanket. Definitely helps keep the flue temperatures higher.
Still just getting 7hrs from load to a cold stove.
When it got cold last week if I stayed up on it I could get 7-8 hours between loading with it still producing heat. Thermostat set at 72 andbthe house at 70 when I reloaded. There is enough heat and coals that it only took 20 min to have it stuffed full burning.
30 out I can get 12 hours out of it now. I have still got a few puffs this week and they come when I load it and the draft fan shuts down soon after. I’m starting to increase the temp and leave it run 45min to an hour and I will see how that does. They have been in contact with me about how it’s doing. I’m happier just not satisfied yet.