Completely confused about new furnaces. Help me please.

I am at a loss about what to do. We need a new furnace and central air unit. We are on propane in this town which is in a rural county in NW MO. The house is over 100 years old, Dutch Colonial. 1536 sq. feet. Furnace is 40+ year old Amana, not sure on AC. Most of house is off of one breaker meaning a small electric space heater will trip it, until 4 years ago, fuse box was the old glass round fuses. New breaker box installed then and breakers put in but wiring is what was in house when we bought it in 2006. Insulation will be blown into attic when find someone to do it. Main part of house is 12 inch or more walls. This past winter was hard and used 1800 gallons of propane, of which 250 is still in tank, so 1550 gallons of propane. Winter here was brutal, temps consistently below 10 degrees F for weeks at time, 2 months of that, and lower. House is not completely tight around doors, windows sealed with plastic. 2 bedrooms upstairs of which one has vent shut, although not completely due to style. Other bedroom vent maybe 1/4-1/3 open on the wall which keeps room okay. At some point both of those won't be used, spousal unit is 75 and stairs won't be an option anymore. 10 floor vents downstairs. 1 wall vents in each of the 2 bedroom upstairs.

I have spoken to 2 heating contractors for costs and installation. I have gotten conflicting information, and am not sure what they are talking about to begin with in much of this. Hence my plea for help.

Things I do not understand: Heat loss per hour. HE Furnaces run most of the time to heat. Pipe is exhaust/drain pipe out side of house. Can't use the old chimney flue. Furnaces have lockout system now and shut down if load isn't right. Using propane ventless space heater to supplement heat downstairs will not tell thermostat house is warm. 95% of heat made will be heating the house versus maybe 50% of it now going to house. Condensation is a problem with new furnaces, and pipe needs to be run slight angle 1/4in per foot back to furnace. Will furnace running more be expensive on electric. Do they make no 'simple' furnaces now.

One has said will need PVC run across ceiling to wall and out for 95% HE furnace. He did the calculations and said 77,000 BTU 3 ton 14% would be his choice, Rheem brand. He said doesn't see cost effective way to be able to use a 80% furnace that won't have to have PVC pipe run across the ceiling. Has been in business 20+ years. Can put it in first week of May. He came out to make estimate within days of calling him, and got back to me same week with recommendations.


The other said 80% furnace, he installs Lennox, would not have to have pipe run across ceiling to vent/drain outside. And could use the old chimney flue being used now for this old furnace. He is much newer to this whole thing than the Rheem man. He took longer to get back to me about estimate and didn't call to tell me he wasn't going to come day he had said first, he did come week later and look at this, I haven't heard back from him on recommendations at this point or timeline of when could install. He is young and maybe done this under 5 years.

This is a big expenditure of course but main thing is I want to make sure this makes sense to people who understand what is going on. I understand horses, sewing, pets and some other things. The only thing I understand about this is I understand nothing at all.

Any help would be greatly appreciated.