People around the world live in various places where there are different conditions. Some people need to heat their houses a lot more than other people do. In North America, you can find many states where winters can be very severe. One of the most cost-effective methods of heating I have ever heard about are outdoor stoves. You might have seen some people using them. In fact, they are the most Earth-friendly solutions a person can think of. If you think of the situation in the world right now, you want to stay self-sufficient and not relay on foreign fuels, such as oil or gas. Using wood instead of oil or gas can mean total independence and being self-sufficient. Americans have a never-ending supply of wood. This means that installing an outdoor wood furnace is a viable solution. If you would like to know how a furnace like this operates or looks like, then feel free to read about the topic. This should give you an idea how you can have one of those on the back of your house. I think that such furnaces are a quite interesting solution and I am surprised that they are not more popular.