What Happens When Steam Pipe Insulation Is Removed? It's Worse Than You Think

When I first bought my house the entire basement had zero pipe insulation. We also had zero insulation in the walls and drafty windows. No main vents either so the whole system had to vent through the undersized radiator vents.

I swear it felt like we had radiant floor heating. The basement was in the 90's and by the time the radiators warmed up the floor was already toasty.

I installed 1 inch insulation around the pipes and it made a huge difference. Basement stays in the upper 50's now and with main vents the steam hits the radiators in a fraction of the time. I may go with thicker insulation some day…but probably not.

I'm a huge fan Ray and so I will share that condensate in a main near the boiler does not cause steam to collapse (unless it's cold and lying in a valley of course—not what we're talking about here).

In fact, when those drops of condensate form they usually get turned back into steam by all the hot steam flowing past them. I have seen it with my glass pipes (similar to the illustration you have in your video, except without all that water lying in the bottom).

Yes, as you get farther from the boiler the condensate will flow at the bottom of the pipe, but you are also getting all the condensate from all the radiators at the bottom of that pipe (the farther you go, the more of this "radiator formed" condensate you get. And yet the pipes don't knock, and the system isn't overwhelmed.

I'm speaking of one-pipe here which is the more drastic of the situations (due to all the extra "radiator condensate" the main sees). With two-pipe it's even less of a concern since the radiator condensate follows a different route, not through the main.

If the lack of insulation were important to the operation of the steam boiler, as you indicate in your video, you would experience all this water hammer every single cold startup. But this doesn't happen (at least not in an installation even remotely following manufacturer design). The cold pipe gets warmed gradually by the initial steam produced by the boiler.

And those uninsulated pipes condense WAY WAY more steam during cold startup than they do when they are hot (yes, even when uninsulated). We know that a pipe gives off a little heat, but a pipe alone can't heat a space of any size, you need radiators.

Absolutely, uninsulated boiler room pipes might (might) be putting heat where it isn't wanted or needed, but they do not cause hammer or other harmful conditions.