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Conversion from steam to hot water

I purchased an 1873 Victorian for restoration and living and have a steam boiler. I'm considering the conversion from steam to hot water, but I'm concerned that I'll need to destroy portions of the architecture to achieve that. The first 2 stories of the house are heated, the 3rd isn't (yet). All rooms have steam radiators, single pipe feed and the house seems to be pretty warm in the cold weather. I'm not sure how much oil is consumed and I'm afraid to find out. I'm hearing more about converting and using PEX piping as the solution to modernize the system once a hot water system is installed. I'm open minded about installing a new steam boiler but haven't found a qualified installer in Greene County, NY. Thoughts regarding conversion vs. replacement?


  • AbracadabraAbracadabra Member Posts: 1,938
    Conversion away from steam???

    Don't convert or replace.  Use the steam system you have in place. Why are you even considering converting or replacing?
  • BobCBobC Member Posts: 4,409
    Do you feel lucky?

    Before you start down that road consider the following. Those radiators and plumbing have been operating on very low pressure for a very long time, forced hot water operates at 10-20X that pressure. You may find some parts start to leak and you may be forced to open walls and ceilings to repair whatever pops AND the first leak may not be the last one. Second those radiators may not put out enough heat because of the reduced temperature, 180 for hot water vs 212 for steam. If your getting advise from contractors who want to just rip out the steam consider they may mot understand steam so the are suggesting a solution that they are comfortable with and that they are not spending their own money.

    If you change over be ready to rip everything out and replace all the plumbing and radiators and consider how expensive that will be. You could probably pull a hot water loop off that boiler (assuming it has the capacity) if you find you need heat on the third floor and leave the steam system pretty much as it is.

    You said the heat seemed to work well and you were concerned about the operating costs. A properly operating steam system can be very economical. Post some pictures of your boiler and the piping around it so we can suggest ways of making it more efficient.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge

    There are many risks involved in converting to FHW. In addition if you have one pipe steam you would need to run a second pipe to each and every radiator. There are many economical ways to save money without converting. Post pics of the boiler and all attached piping(don't stand to close when taking pics). Also post pics of end of main steam pipes. Also try to get the modal # of your boiler. You can also post pics of your radiators so we can determine if your boiler is properly sized. Include the height of each radiator(from floor to top of radiator.
  • Jamie HallJamie Hall Member Posts: 6,659
    Don't do it

    There is no need at all to make such a conversion -- not that it can't be done; it can, and sometimes it doesn't cost that much more than getting the steam system to work properly.  Sometimes, however, you will find that all radiation has to be replaced, as well as all the piping and the boiler.  Since you indicate that this is single pipe steam, you will almost certainly wind up replacing everything as well as running all new piping.  So why do it?

    Steam is simple, reliable, and very quiet.  You may not necessarily find a qualified installer in your county.  However, there are some very good men in New York City and in Lenox, MA who would, most likely, be able to come and assist you.  Try Find a Contractor looking under the States (New York and Massachusetts)

    With regard to running cost, the difference between a steam system which has been properly maintained and is running well and a new, high efficiency hot water system is minimal -- a few percent.  In your present situation, I can almost guarantee that you will never recover the cost of the changeover.

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-McClain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • Dave in QCADave in QCA Member Posts: 1,660
    edited January 2012
    I have seen the disasters!

    There are a lot of advances being made in hot water and some of the systems can achieve a very high efficiency.  However, the cost of operating pumps is usually left out of the equations.  Also, is the fact that the super efficiency boilers are packed with high tech devices that are prone to fail, sooner or later, and maintenance calls can more than eat up any fuel savings.   Also, one has to remember that the super high efficiencies on hydronic systems depend on operating at a very low temperature.  If you get up above 134F, the condensing part no longer works and the efficiencies drop in the 80-86 range, the same as a good steam boiler.

    I have personally observed the conversion of a couple of good old steam systems.  One in particular was engineered by a mechanical engineer in a big firm that was supposed be competent.  It was a one pipe system, so piping had to be added.  It was an expensive undertaking.  In the end, the system never worked right and there was no way to ever fix it.  The end result was that thousands of dollars were spent, heating costs did not go down, fuel use did not go down, and unfortunately, comfort levels did go down.

    The popular, but erroneous notion in the HVAC business is that conversion is a good idea.  The knowledgeable advice that you will get from the pros that actually know and understand both Steam and Hot-water heat is, DON'T DO IT!
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
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