In the best of all possible worlds (which does not exist), those manufacturers who sold tens of millions of dollars worth of the things would have to chip in and allow you to upgrade cheap....share the pain a bit. On the other hand, a very efficient unit in the USA might get the 30% federal tax credit and do even better when and if the new Home Star Energy thingy passes. Please take my insider word in this - the OWB loophole was VERY intentionally taken advantage of by the makers.......this is not an issue that was win-win-win, but more of an issue of "I see an opening to make money by skirting the spirit of safety and air pollution regulations". Another interesting FYI. In the earlier time of OWB, you would be very luck to get more than 7 years out of a unit without a lot of leaking and in many cases replacement. I'm sure units have improved and people got smarter about water treatments, etc. - but still 10 years is a valid lifespan considering the history.