Yeah, I've sat around more than a few barrel stoves in some hunting camps and I'll guarantee you one thing. They work fine. Maybe not the most asthetic stove you'll ever see. But you won't have a problem with the thing throwing off heat.
You don't need double walled pipe to make a stove safe any more than you need a push button safety on a lever action rifle to make it safe. Wood stoves existed in people's homes for hundreds of years before double walled pipe came out. You do need some common sense in terms of how and where you set up a stove with plain stove pipe. And you do need to maintain it to keep it free of creosote buildup.
But this is a viable option for emergency heat in you home and if you are a hillbilly it might be your only option.
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