Welcome to our forum.
It's amazing how often this homemade thing ends up costing more in the long run. You're buying parts instead of a whole, which makes it appear cheaper. I went into home brewing beer thinking I'd save money.Right.......... For the money I spend vs the quaility of beer I produce I suppose I may in theory same money. I get really good quality beer for the price of the lower priced commercial stuff. but it can take a long time to recoup equipment costs.Unless you call it a hobby, which by federal law says that you can overspend all you want.
I'm not sure I'd want to mess with a fire to keep a hot tub warm. Tending a fire to keep the sucker heated wouldn't be my idea of fun. Especially in the dead of winter or the humid hot days of summer. No Thanks. I'm with Drewstar. Give me my 240V spa any day.But it is facinating to see what people can create.