There's a crawl space or basement? I assume one story. Ductwork can be installed below with floor registers. You'd have to find a way to get a duct and return to attic.

"I hate individual mini split cassettes and visually they would ruin the beautiful walls."

There are also indoor units that can be:

• Mounted under the floor or above the ceiling
• Mounted in the ceiling
• Set on the floor

These above are Heil products that are also sold under Carrier, Bryant, Arcoaire, Comfortmaker, Day and Night, Keeprite, and Tempstar brands. They're all the same.

Yes a full basement with two rooms finished and the laundry is down there. Thank you @wdccruise I will check into those links. A constraint is not using any heatpump due to extreme cold in winter. Read about dual fuel also but thinking will just be separate furnace and a/c. thanks for the help

"A constraint is not using any heatpump due to extreme cold in winter."

Perhaps you could the heat pump for heating (at all but the coldest temperatures) and cooling with the existing furnace as backup. My Honeywell T6 Pro thermostat (page 9) supports a heat pump with "Gas/Oil Forced Air" as backup and emergency heat source. Depending on the price of fuel, perhaps it would even cost less to heat the house with a new, efficient heat pump.

I have ground source heat pump. I turn off the strip heat, so if it's really cold it takes awhile to heat (I turn thermostat down when I'm away). If you could turn off strip heat in air source heat pumps, your floor furnace could kick in at a preset temperature.

Does this house have natural gas? If so what are the gas and electric rates?

The winter low design temperatures for the Shenandoah Valley is about 15 F degrees. A heat pump would work at these temperatures with back up heating. The backup up heating could be electric resistance heating. If gas is available then it may make more sense to install a gas furnace with an outdoor AC condenser. The installed duct work with provide heating and cooling.

There is a gas floor furnace with a large grate in the main hallway.That is the only heat supply and it simply allows the heat to rise there is no fan etc.If you lived in a house in the 50’’s everyone had this. . Picture below.

Keeping the old gas furnace seems to be the best option since it works and is in place. Original to the 1956 house. Adding the heat pump for a/c and mild cold seems like the best route to get a/c and duct work.

• Heat Pump Buying Guide
• Energy Star Certified Heat Pumps (split systems; at least 15 SEER and 8.5 HSPF)

update: inspection showed the furnace is 35 yrs old and the pilot was not on and the unit appeared to not be in use recently. The people in the house had closed the manual flue in the fireplace and were using gas logs to heat the house !! No CO detector anywhere in the house. What idiots.

So we are going to lower our offer based on this info as well as it needs a new roof asap as well as some other less serious but multiple issues. Thank you for all the info included here. We will be looking at the dual fuel systems furnace with heat heat pump for a/c + heat when temps not too cold. Since there is no duct work and there is plenty of access in both the full basement and the improved attic space which has accessible knee wall storage areas we should be good to go.