There is one property right now that I want to put an offer down for that has a renovated basement with 6 ft ceilings however there are sections that are under the required height limit for some duct work.

Installation of Navien combination boiler / tankless water heater, air handler with ductwork for two-zone HVAC, outside condenser, and Fujitsu ductless minisplit in family room on slab.Installation of 500-gallon liquid propane tank underground and convert from oil to LP.Installation of 1,100 SQFT of 5" x 3/4" French Oak Pacific Grove hardwood flooring with new OXB underneath.

(I budgeted for this in my purchase price)So I see 2 options:1-replacing boiler and radiator:$59002-I thought of taking this opportunity to switch out the boiler only on first floor for a forced air unit, run the ductwork under first floor in basement, and use the first floor radiator upstairs. ( maybe I could sell the remaining ones on CL to recoup some money) I am waiting for an exact estimate but his first thought was in the area of $7000-$7500.

It was an old water heating system that had to go but I didn't factor in enough for the additional duct work that needed to be added for a forced air system.

@Alex Bekeza apparently the ductwork cleaning is only $200.

Removing plywood over subfloors is giving me anxiety.On the positive, It can provide easier access to plumbing, wiring, and sometimes duct work.  

If you aren’t removing all of the ductwork and replacing it, your number for the HVAC is way too high.And washer dryer pairs are usually less than $2000.

The old gravity furnaces on the other hand, I don't hate (except fo the asbestos tape around the duct work and it's not usually a problem if you leave it alone)-- They are very inefficient (60%) but there is nothing at all to break, they work even in a power outage, and they put out serious heat.

Especially when the alternative is retrofitting ductwork or using potentially improperly placed retrofit ductwork.

I realize there's a fair amount of install cost for mounting the unit, wiring the unit, and installing ductwork, but it seems like it could be done for a ballpark of $4k-$5k per unit (I'm using a 2 bed/1 bath with about 750 sq ft as my example).