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Thread: Insulating steam pipes

  1. #1
    DIY Junior Member yellowjacket's Avatar
    Join Date
    Aug 2009

    Default Insulating steam pipes

    I bought a multi-family a few years ago which has steam heat (radiators) for the two apartments on the 1st floor. The previous owner had the asbestos removed from the pipes in the basement and the tenants tell me that the heating bills are through the roof.

    My question is what to use to insulate them. I've seen the insulation pipe wraps with the foil on the outside at home depot. I've estimated that it will cost me $1000 to do the job. I'm not overly worried about cost as I want to keep my tenants happy.

    Any feedback would be appreciated.

  2. #2
    Plumber Winslow's Avatar
    Join Date
    Dec 2005


    If you're not worried about the cost why don't you hire someone to do it, it should be tax deductable.

  3. #3

  4. #4


    Look for fiberglass pipe insulation with "all-service jacket" ASJ. It's white, not shiny. Also, don't buy it at Home Depot. They only stock 1/2" and that's not thick enough. Assuming you have a 2" mains you want 1" minimum thickness. ASHRAE code is 1-1/2". You can also find PVC fitting covers to insulate the elbows & tees. It's especially important to insulate the near-boiler piping.

    While it's not hard to do this yourself, it is hard to make it neat. Also, this insulation gets cheaper when you buy it by the trailer load. A contractor might be able to do the whole job for about the same as your materials cost.

  5. #5
    Plumber jimbo's Avatar
    Join Date
    Aug 2004
    San Diego


    We had steam heat in the house where I grew up. Over the years, a lot of pipe insulation either fell off, or was removed in the course of repairs/add ons, and not replaced. So there was a lot of bare pipe. The house was always toasty cozy. I just assumed any heat off the pipes came up into the house anyway. Couldn't tell you what the impact on the heating bill was.

  6. #6


    It's not just the heating bill. Heating uninhabited space is wasteful, but more importantly, steam systems were designed to run with insulated mains. They didn't put asbestos on the old systems to save money. If you run a steam system into cold uninsulated pipes you will create too much condensate too quickly, resulting in hammer, wet steam, and spitting vents.


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