Bought a house built in 2003 a few years about a decade ago, has an older Water Furnace Premier 56 system. Recently noticed a spike in my electric bills, turns out there's a leak in the evaporator coil. $2060 to replace the coil with a new aluminum one. However, the repairman made a good case that with R22 phasing out, the 30% tax credit, and the new models having double the efficiency of my old one I'd be better served to replace with a newer model. Company specializes in geothermal. House is a 2733 sqft ranch in Cleveland, Ohio, horizontal ground loop. I'm leaning toward the replacement options he quoted, but he gave a few options which I don't entirely understand: First is to put in a 5ton Water Furnace 5 series dual capacity with hot water assist, 20KW aux heater, digital thermostat. Reuse the existing two-pump pressureless flow center. $14,000 ($9800 after tax credit) Second is to do the same but replace the pressureless flow center for an additional $1900. Third option is to put in a 5ton Water Furnace 7 series with hot water assist. Comes with a touchscreen thermostat and variable speed dual pump flow center. $18600 (13,020 after tax credit) I think I understand the tradeoffs between the 5 vs 7 series (quieter, more efficient) but it seems unlikely I'd break even on the $3200 cost difference. On the other hand, I have a 16 year old flow center which I assume has a limited life span, and the additional cost of replacing that brings the costs a lot closer together. Did they suggest replacing the flow center as an option because it has a limited lifespan? What are your thoughts on these options?