> Ground source scales well if you have a large building and a large body of water near by then the payback time is short. But at single family home level it's

> Ground source scales well if you have a large building and a large body of water near by then the payback time is short. But at single family home level it's just not that useful. There is a way: open-loop systems. A few years ago we installed an open-loop ground source heat pump (ClimateMaster brand) for under $6k. Water at 50F is drawn from a preexisting 15 gpm/50 foot well, through the heat pump unit, then dumped in a dry well at around 40F. It uses half a million gallons of water a year (costing <$30 in electricity), but of course there's no aquifer depletion, and closed-loop systems also use energy to pump water. This unit also pre-warms hot water at its coefficient of performance (about "600%"), reducing electric DHW costs. We homeowner installed, so we weren't eligible for NYS incentives. But it cut our annual bill in half vs. the previous heating oil furnace, with a payback period of 5-8 years.