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Steam Pipe Insulation Specifics

John S.
John S. Member Posts: 260
The general idea of insulating is to keep as much heat as possible inside the supply piping of the system and to the radiators. Uninsulated steam pipes will do several things.

1. Heat portions of the building that were not meant to be heated via convection/radiation from the pipes themselves.

2. Make the steam that is supposed to supply the radiators condense faster, therefore, potentially working the boiler harder than it needs to work to satisfy the thermostat.

The original designer of the system sized the individual radiators based on a heat loss study of the building. Then, the boiler was (or should have been) sized to match the load of all the combined radiators & piping. That being said, the pipes should not be in the equation as far as being an actual heat source.

IMHO, it is wise to insulate all steam piping with an exception. If you find your basement to be extremely cold, then maybe you would leave the header piping uninsulated. Othersie, I would insulate those as well.

As far as wet returns, insulating them won't hurt a bit, however, you probably won't get a return on that investment nearly as quick, if ever. By insulating the returns, you're simply not allowing the returning condensate to go as cold. Therefore, the next time the boiler fires on a call for heat, it will not require quite as much btus to heat that water. (it takes more energy to heat 140* F water to boiling than it does to heat 180*F water to boiling.)

I am not an expert like some on the "Wall" but hopefully you will get some input from a pro as well.

Hope this helps.

Comments

  • Scott Kuchta
    Scott Kuchta Member Posts: 9
    Steam Pipe Insulation Specifics

    I know it's an exhaustive subject that I've seen posted many times, but I still have questions. When I read Dan's book he said "insulate those mains". My pipes were bare so I did. Went to a heating supplier and got the nice fiberglass preformed stuff along with the covers for the 90's and 45's. I started at the boiler and insulated EVERY pipe in my basement that is connected to the boiler right up to the bottom of the first floor. What a difference - I have heat on the second floor now! But then I got to thinking (dangerous) because an engineer here at work said I may have over done it. I have a one-pipe steam system. The house is an ell so I have two "mains" that are big pipe, say 2.5 inches that run most of the length of the two wings of the house. Take offs (still going horizontally) and the very beginnings of the risers (vertical) are smaller, say 1.5 inch. The dry returns are 1.5 too.
    I guess my question is did I do the right thing? Specifically should I have insulated the "near boiler piping", the wet returns and all? Should I have insulated EVERYTHING? Does it even matter? I did not insulate the risers going through the first floor to the second floor radiators because of aesthetics - should I insulate those as well?
    Reading Dan's book, I realize this is a complicated system and I just want those specific questions answered so I know I didn't create any new problems by "fixing" one.
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