First some background: House is 2 stories + finished walkout basement. All 3 floors have hot water baseboards heated by oil fired boiler (~1980 vintage). Upper 2 stories have forced air with a 4 ton heat pump (A/C & heat) which is ~10 years old. There is zero ducting to the basement currently and the air handler is in the attic while the boiler is in the basement. Oil system, both boiler and oil tank, are at end of life and I'm evaluating a geothermal setup as an all-in-one replacement for the oil and existing heat pump. I've had a few contractors out to discuss options and am looking for some input from the community here on I believe my options for geo are as follows: 1 - Replace oil system with oil system (we're too far from gas line, only fossil fuel alternative is propane which should be more expensive for baseboard water efficiency levels). Lower up-front costs, but higher overall costs than a geo system (depending on assumptions) after only 1-3 years based on current consumption of ~$3000/yr in oil. 2 - Totally disconnect all baseboards and go fully forced air. Will require some duct work to get airflow to the basement, slightly concerned about getting sufficient ducting to heat the basement. In the past running the boiler alone, without activating the basement baseboard loop keeps it at ~62-65 all winter which is sufficient for its current minimal use but need ability to heat a little more in the future. Would need to get enough air to the basement to replace the ambient boiler heat at least. The fully forced air system has the advantage of higher efficiencies (it appears base on my geo research) of water to air GSHP systems vice the water to water. Disadvantage of having lots of unused baseboards and copper piping. 3 - Try to feed the baseboards with geothermal (via a WaterFurance OptiHeat) low temperature hot water that can also supply the air handler with hot/chilled water or a unit can has both capabilities like a Synergy 3D that uses a split air handler (which doesn't appear to exist). It seems like that kind of setup would be more expensive with lower efficiency than a fully air system but would have the benefit of continuing to be able to use the baseboard infrastructure. I can imagine it would also be difficult to tune/control the thermostats to get the baseboards and forced air heat to work in concert since getting my existing systems to work together was basically a waste of time. So thats a lot of long-winded background, but i'm really interested in anyone who's faced a similar setup that added geothermal and which way you went and if anyone has any guidance or tips in general they'd like to share. Thanks in advance - Cheers!