The kinetic energy of the mass of exhaust gas carries it along the exhaust pipe, and causes a pressure build up ahead of the mass of gas and a partial vacuum behind it. This principle is used in a tuned exhaust system.
Culligan - $2352 ($2053 w/o R/O unit) Culligan Gold Series (10), Good Water Machine. If I were to look at price only, I would go with either the cheaper Ecowater system w/R/O at $2698 or the Culligan system. At almost $4k, the Kinetico system seems greatly over priced.
Costs and energy savings of gas-fired tankless water heaters: Quebec-quÃ©bec based natural gas supplier and, Distributor Gaz, metro mÃ©tro estimates ataround $ 525 the average additional cost of acquiring-a gas fired instantaneous. water heater study carried out by the Canada Mortgage and Housing Corporation (CMHC) estimated at around 230 m3 the annual water heating savings achieved with a gas-fired instantaneous water heater; at a cost per cubic metre of natural gas at $0.30, this represented annual savings of $69.