@Roy N.
All valid points. I yanked out the oil and put in an on demand combi propane boiler for DHW and hydronic in floor radiant heat in my primary residence. Insulated and sealed to the gills and would highly recommend it to anyone who is doing a rebuild to the studs.
The property I am buying has forced hot air and I'm not going to rip out the ductwork, so new heating systems will need to be FHA. I love the efficiency and energy savings of a dual propane and heat pump system, but since I would like to keep the tenants paying the heating bill, I don't think it would get me any additional rent to justify the cost.
The plan as of right now will be to test the units at inspection and hope they will last through the winter. 4 of 6 units have had tenants in them for many years, so I think its safe to assume that they had heat last winter, and I will be dropping by to ask. Come spring, I will have a plumber/hvac tech rough in all 6 gas lines for propane and then replace the furnaces in the summer/fall. This will allow me to pay for the upgrades with the rental cash flow and stagger the costs so I don’t need to pay out of pocket up front. Additional benefits would be no need for chimneys and no chance of CO poisoning, less chance of environmental damage from oil tanks, and less ongoing maintenance. Anyone see any flaws to that logic (other than the obvious potentially dead furnace)?
My main concern was that there may be some sort of propane cost bias from the tenants. My math tells me that it’s roughly the same total cost for heat due to the higher efficiency of the propane vs the cheaper cost of oil fuel.
Thanks!