Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Are these good enough reasons to convert from steam to FHW?

kurtz Member Posts: 1
Hello Everyone,

Thanks for the excellent forum and advice!  I would like to ask if our situation would warrant going from steam to FHW?

For a bit of background on us, we have an oil + 1 pipe steam system now, and the boiler is 30+ years old. We just moved into this 1920's house, and it is around 1900 square feet + 500 sq feet of finished attic space, and is heated by 11 radiators currently (5 for the 2nd floor rooms upstairs plus 6 downstairs).  We have no idea how well things work, as we moved in during the summer.  But, we know oil bills ran quite high on this old system. We would like to replace the current system before the winter comes around (ie NOW) with a natural gas system and are looking at FHW vs staying with steam.

We are considering converting the steam system to forced hot water (first floor) + hydro air (second, third floors).  We're happy to hear any advice.  Here's why would we move away from steam:

1. Piping & boiler location are changing in the basement

a. Some of our current dry return basement piping hangs

down as low as 10" below the ceiling -- given all the complexities of pitch and steam/condensate return flow we're going to have to re-pipe most of the basement-area-underside first floor radiators because of the desire to refinish the basement.  We also have a significant portion of wet return pipe that was once buried in the concrete and was moved to be flush on top of the concrete (old pipe probably failed), which also runs across a doorway and around the basement (you have to step over it).

b. We would like to refinish the basement,creating a slightly raised floor and drop-ceiling.  The wet-return on the floor and the dry-return pipes 10" below ceiling make the refinishing of the basement hard.  Long-story short, we're re-piping the 6 first floor radiators.  If we're already going to re-pipe why wouldn't we go forced hot water?

c. Our radiators are connected across top, but would need a bleeder valve installed and the steam valves removed.  I know it's risky they might leak, the worst case scenario we'd replace all six.  (obviously the caveat here is that we do the EDR calc and make sure the HW at a lower temp can heat the house, and we will!)

2. The second reason we'd consider moving away from steam is because we want to install central AC, at least upstairs, which means we're running new ductwork in the unfinished part of the attic (3rd floor) and putting a vent in each bedroom ceiling plus our 1 bathroom.  That ductwork exists, and the radiators currently cause havoc on 4 small rooms with furniture placement.

3. Zoning, we would like the first and second floors to be on different zones.  If the second floor has ducts, why not just make it hydroair with a FHW pex run to the attic.  This would also remove 6 radiators from the second floor.  Since heat rises from the first floor, perhaps not so bad...radiators FHW first floor, hydro air second floor.

4. Hot water, we always seem to run out of hot water and I can't say I trust the instant ones -- so a superstor type tank is preferred for many reasons (reliability, efficiency, and the fact that they have a have a lot of gallons per refresh). I can't run a superstor off a steam heating system, can I ?

5. Efficiency -- yes, efficiency is important to us.

6. Lastly -- we'd like to put in addition on in 2-4 years, but are not ready yet.  This would mean adding 500 to 1000 square feet to the house (from the 1900 main to 2900 say).  It'd be ideal to put in a system that could handle this.  Isn't this another reason to go FHW/zones/modcon?

My overall questions then:

The idea of FHW first floor, converting the steam radiators, plus hydro air second floor, plus superstor -- bad idea, good idea?? Or am I off base?


  • Steamhead
    Steamhead Member Posts: 16,832
    edited August 2010
    I wouldn't do that

    there are ways around all these issues that are much less risky.

    First, the basement piping can likely be rerouted. A dry return can be replaced with a wet return, and if you use copper there is no problem with running a wet return under a door. We've done it.

    Why do you want to move the boiler? How far do you want to move the boiler away from where it is now? Will it still be close to the chimney? Maybe the new location will solve some of your return issues.

    Hydro-air is basically scorched-air with almost all of its disadvantages. The only advantage hydro has over the usual furnasty is that if the heat exchanger cracks, you'll get a water leak rather than a carbon monoxide leak. Use your ducts for A/C only- moving air is great in the summer but not in the winter, especially when colds and flu are going around.

    You can use a SuperStor-brand tank with a steam boiler. They work well.

    You can control each steam radiator individually using the proper thermostatic air vents. These respond to the room temp and shut off the air leaving the radiator so it doesn't heat up any more, allowing the room to stay cooler.

    Sounds to me like your addition will be just big enough for its own little boiler. So you could put in a properly sized steam boiler now, and put in another boiler later for the addition. That way if one boiler broke down you'd still have heat in part of the house.

    I have a feeling you've been hearing some people who don't understand your steam system and/or just want you to pay them for a messy, expensive, disruptive demo/complete replacement job. If you take their advice, you'd be less comfortable and not save any money.

    Where are you located?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Dave in QCA
    Dave in QCA Member Posts: 1,785
    edited August 2010
    Building a case....

    From the perspective of a person who appreciates older buidlings and all of the great work that went into them.....

    It seems to me that a person can build a good case to do just about anything that they decide that they want to.  You have presented a pretty lengthy list of reasons to support your proposed plans.   Have you also tried to build the case for keeping the steam system with a new, more efficient boiler?  I bet you could develop a pretty lenghty list of reasons to justify preserving the system as it was installed.  Steamhead makes a very strong case.  He is a pro and knows what he's talking about. 

    Also, when you install AC, if your AC system is only doing AC and not heating, it will be easier and less costly to install.  I had a 2100 sq ft 1906 foursquare a few years back.  It had a pretty mucked up hot water system.  Straightening out the system involve replacing radiators that had been moved, moving others back to where they had originally been located.  (the house was the unfortunate victim of being chopped up into multi-family)  Also, had to replace the boiler.

    Put in a new AC system with the air handler in the walk-up attic.  Single return in the ceiling of the upstairs hall.  Easy installation of a ceiling supply in the rooms on the second floor.  Was able to route supplies down to the first floor through chases created in closets, etc.

    When completed, the AC worked wonderful!   The cast iron radiant hot water worked wonderful.  And, the integrity of the house was maintained and a HUGE amount of money was saved. 
    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.
  • Jamie Hall
    Jamie Hall Member Posts: 23,275

    What you are talking about, bottom line, is a complete tear-out of the existing steam system, and installing an all new hot water system.  I would be exceedingly surprised if you could save any money at all doing that.  I'm with Steamhead -- one of the very best in the trade.  Get a good steam person to rework your existing system with a nice new boiler (which will take care of the efficiency issue) and separate air.  And be happy.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
This discussion has been closed.