The Lost Art of Steam Heating w/ Dan Holohan (PODCAST)

In today's podcast, Bryan talks with legendary Hydronics author and trainer Dan Holohan about the history of steam heating and some practical applications of old ideas. Recently, Dan has been working on more novels, having published two of them over the past few months.

Steam heating is a “lost art” nowadays; it has become increasingly uncommon and has been disappearing since the Vietnam War. Many people who understood steam heating either retired or died after the Vietnam War. Many elements of steam heating are difficult to understand or surprising. (For example, steam pressure has a surprising relationship with velocity: low-pressure steam moves through piping much more quickly than high-pressure steam.) So, Dan Holohan is on a mission to revive that knowledge and teach the newer generations about the lost art.

There are many older steam heating systems still operating today, especially in the older large buildings in New York. Dan learned a lot about steam heating when working on these old systems and optimizing them. Most of the time, he optimized those systems by removing unnecessary accessories, not adding components like steam traps.

Many old boilers used coal as a heat source. Nowadays, many old boilers have been fitted with conversion oil burners with thermostats, but they are still piped for coal. Some systems now have multiple risers or massive vents on the main riser to prevent the thermostats from getting too hot too early and satisfying the thermostat too early. We call that master venting, reducing pressure and allowing steam to move very quickly and efficiently.

Dan also discusses:

  • The 2-PSI standard
  • Transportation metaphors for BTUs in steam
  • Harmful renovations for old boilers
  • Replacement vs. restoration mindsets
  • Gaps in steam boiler education
  • Monopolizing the market if you HAVE the education
  • Boiler piping and venting
  • Two-pipe vs one-pipe steam

Find out more about Dan and hydronic heating at

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.




To continue you need to agree to our terms.

The HVAC School site, podcast and daily tech tips
Made possible by Generous support from