i have used both types. the in block type is very difficult to install yourself. the hose type is pretty easy. the in block type is generally thought to be superior in operation. i dont know about the cost to use. i would think if you look at the wattage that will tell the usage story. ie if both are 1500watts for example they would cost the same to operate. the cost to operate if used daily is noticable on my bill. i have found that unless it is extremely cold they will work fine to plug in an hour or so before wanting to leave.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.