I actually just replaced a 20-year-old AC system that had a link to the hot water system. Installers just removed the water heater link entirely. Said that the

I actually just replaced a 20-year-old AC system that had a link to the hot water system. Installers just removed the water heater link entirely. Said that the extra resistance and energy involved in the exchange cost more than just venting the heat in modern systems with high SEER ratings. No idea if that's accurate; just what I heard.