Comment Used one for 15 years in eastern Ontario (Score 1) 203
We loved our heatpump -- provided the bulk of our seasonal heating and cooling for 15 years. Was an air source unit -- cost us roughly $10,000 installed. Would have preferred ground source, but the rock drilling required to sink the collection wells would have added another $40,000 to the cost. The heat collection and transfer process becomes less efficient as the air gets colder -- at -10C (14F) the system shuts off. From that point we had to rely on our electric baseboards. Ground source would have been warmer and we might not have needed the baseboards, but uneconomic. As one can probably guess, replenishment rate governs both sources -- the air is always refreshed so cooling it is not a problem. Being in a rural area we had no close neighbors -- which might be a big problem in a crowded urban area. Too many ground source units in a small area could lead to ground freeze-up which would shut everyone down. Glad that Germany thinks this is a solution -- certainly our experience as long as the power stays on.