The only change somewhat easily possible would be putting newer windows in that are more energy efficient than the current 20 year old windows. The furnace is a high efficiency natural gas unit that's only 8 years old. I'd love a heat pump system, but I can cut A LOT of wood for the cost of one. The indoor boiler in the shop heats the dhw and the exchanger in the furnace plenum to heat the house.Tme to make some changes to the house or furnace then.
The house and shop are both r19 walls with r30 ceilings. The issue simply the mass I'm heating in a cold climate (had an entire month of below 0F last winter). The house is 4100sqft with 14ft peaked ceilings on main floor, finished basement, 28 windows total, and 2 sliding doorwalls. The shop is 35x50 but it's 3 levels and 36ft at the peak. I keep the building heated (via in floor) full time as it's my business. So considering my heated volume and climate, I don't think 20-22 cords per 5-6 month heating season is that bad at all.