History of Heat
This post is for Fred.
The BAB has a collection of historical mechanical plants. The building was originally built in 1914 and expanded several times. The first boiler was replaced, but the pad that it sat on is still there.
We think this is where the 1914 boiler lived
The oldest boiler is enormous and a mess. It was originally powered by coal. Tom has plans for the cast iron doors.
Enormous Coal Boiler
The Jacoby folks kept that boiler running until 196o and replaced it with another boiler, powered by gas, that was about a quarter the size of the last one. That old boiler lasted 46 years.
Last relic boiler
The replacement boiler lasted until the printing company abandoned the boiler system and went to forced air. That boiler lasted 28 years.
When we bought the building, most of the cast iron radiators had been removed, presumably sold for their scrap value. That is too bad because the heat from a boiler is very energy efficient and pleasant. What we inherited is a collection of five Reznor XL 170-3 natural gas unit heaters which appear to have been installed in about 1988.
Reznor XL 170-3 that once heated the Red Room
We had a repair man look at the units when the weather turned cold that first year we were working in the place. We were told they all have small cracks in their manifolds. We are still using one in the well-ventilated dock to keep the pipes from freezing, but they all need to be replaced. We pulled the one in the photo out of the Red Room when we converted it to our apartment. The unit heaters lasted about 19 years.
The new system we installed in our apartment is a Unico High Velocity electric heating and cooling unit. We installed a similar system when we added central air conditioning to our little U. City house. We have been very pleased with how quiet and energy efficient it is.
The HVAC unit now keeping us cozy in the apartment
The National Association of Home Builders publishes a Study of Life Expectancy of Home Components.
From that source, we can expect this new unit to last 15 years.
Is this progress?
B. A. B. 
Most excellent! Thanks for catering one of your more obtuse readers. I love the sight of the old coal burner – gosh, if only more of the old radiators remained, a quick burner retrofit to gas might have given the old dog several more decades of use (provided the earlier operators watched the water chemistry). I look forward to seeing what Tom can come up with for the doors! There are also some intersting components and instruments on the old girl that might have some artistic, if not functional elements for re-use or re-purposing..