https://www.pinterest.com/pin/195343702562355034/

I never stated nor implied that Octopus furnaces were not made after the 1930s, but that they were obsolete thereafter. :-)

And, of course, those Transite and non-woven asbestos ducts do leach out such that a blower would spread ACMs everywhere. No fun at all.

We have a 4,200 s.f. center-hall colonial built in 1890, and substantially enlarged in 1928, with a gravity-designed hydronic heating system (4" ID main risers, 3" ID returns). Now it is served by a mod-con 97% efficient (by actual test) boiler. But heating the well over 300 gallons of water in the system (38 rads) is an ordeal on its own. So, we installed mini-splits last January followed by a visit from our gas/electric utility in April to see if we had diddled the meters. When they saw the equipment, they reported that all was well. Point being they heat and cool with a SEER of 29+. We run the house at a constant 60F for heating, and the six rooms that we use the most have the splits in them. Our combined gas and electric bills are less than $300 per month, on average at $0.14 per KWH, and $0.77 per therm. We use gas for cooking and hot water as well (indirect water heater from the boiler). I suspect that mini-splits in your case could solve the entire heating/cooling issue for less than the cost for the removal of the boiler. Just mothball it and seal the ducts.

Peter Wieck
Melrose Park, PA