I'm using an LP gas 40 gallon tank type hot water heater & I think it has a slow leak. I could replace with on demand or tank & I can go with LP gas or electric. What are limitations of on demand for hot water flow? What are operating costs of electric or LP gas on demand or tank hot water heaters? Will a plumber work with electrical hookup turnkey or leave it to me? Any good plumbers in Eagle River,Lando, Conover, Phelps WI area?