I currently have a 3200 Sq. Ft. house with Natural Gas heat for first floor and a heat pump in the attic for second floor. House was built in 2002. HVAC is original and was never serviced by previous owners.

Current setup: 2nd floor (1400 Sq ft) heat pump is a 13 Seer Goodman unit (2 ton) connected to a 2.5 ton attic air handler with 2 - 4.5KW strips backup. Honeywell VisionPro 8000 Thermostat.

1st floor (1800 Sq. ft) is 92% Goodman gas furnace with 3 ton standard AC unit. Honeywell IAQ Thermostat

Current system handles house well (comfortable, keeps up fine). House is very well insulated for Maryland. (Heat pump looses refrigerant, gas furnace had a cracked secondary combustion chamber) - looking to replace both systems .... last month 3000KW electric usage, natural gas usage not that bad (also covers fireplace, hot water heater and stove).

My yard size (4 acres - wide open) would support a Geothermal system (horizontal system may be preferred due to cost and efficiency). Soil is clay.

I am considering a system with one combination geothermal unit/air handler for the 1st floor (~3 ton unit in basement) and a second split system with geothermal unit in basement (~2 ton) with air handler in attic.

For backup, I am considering a high-effeciancy gas boiler that would be zoned and connected to a hydronic coil in the basement air handler and another hydronic coil in the attic air handler.

Another option would be to install high efficiency gas furnaces as the backup to the geothermal systems (instead of the hydronic systems).

Looking for pros/cons of such systems.

Our local HVAC company can install any/all of these (our choice).

Current Heat Pump system w/electric backup is sufficient but expensive to run during December through February with the temps here in Maryland.

Thanks in advance for suggestions/ideas.