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  1. #1

    High Efficiency Gas Boiler with Iron Radiators and Pipes?

    Hi Everyone,

    I live in an older home with hot water oil heat and big old iron radiators. I am in the process of getting estimates on converting to natural gas. My current boiler is pretty new (8 years).

    Two people who have come by have told me that I should just convert the burner given the age of the boiler. Further, one person told me that a high efficiency boiler has lots of condensation that would be a major service nightmare with iron radiators and pipes.

    The man identifying where the gas meter would go also told me that I should do a conversion, and that folks would try to sell me a new boiler when it wasn't necessary.

    So, a third guy was just out this morning who told me that I would be very disappointed in the savings if I didn't go with a new high-efficiency boiler. He told me that the condensation would not be an issue. He also said that converting it would be very inefficient -- lots less than it is currently with oil -- like it would end up being around 70%.

    If anyone can give me any insight on this, I would be very grateful. Thanks so much!

    Kind regards,

    Mary

  2. #2
    Join Date
    Jun 2008
    Location
    Lancaster Pennsylvania
    Posts
    60
    I usually recommend replacement of the boiler with a high efficiency system.

    Some of the things you are being told are true.

    When you convert a oil burner to a gas burner you lose efficiency.
    This is true and it typically is around 70%
    What is also true is that you are going to still save some money with converting from oil to gas. I am not sure what you are spending on oil or gas. But for example
    oil at $3.75 Per gallon burning at 80% efficiency would cost $33.80 to get 1 million Btu's of heat.
    gas at $1.15 per Therm at 70% efficiency would cost $16.43 to get 1 million Btu's
    and gas at $1.15 per Therm at 95% efficiency would cost $12.11 per 1 million Btu's.

    So you can see that natural gas at today's prices cost much less then oil despite the loss in efficiency.

    High efficiency boilers do create condensation but it is all internal in the combustion system and has no effect on the piping or radiation system.

    One place I am not seeing mentioned is what is being done with the chimney if you do an oil to gas conversion?

    If you have an old brick chimney you really should have a liner installed to make sure the system vents correctly and does not damage the chimney.

    One other concern with most oil to gas conversions is that it is not what the manufacturer intended for that system. You should make sure that someone checks with the manufacturer and make sure that its ok to convert it.

    I have always been uncomfortable with the conversion idea, but I am a salesman not a technician
    Good luck with your decision, anyway you go you will save a ton of money going to gas.

    Jordan

  3. #3
    Join Date
    May 2004
    Location
    Frederick, MD
    Posts
    995

    Whoever

    you contract must know how to properly pipe the new boiler. It IS possible for condensation to be created in the boiler if precautions and piping techniques are not followed. And as was mentioned, you will probably need to line the existing chimney (unless of course they use PVC for the intake and combustion vent).
    GO NAVY, BEAT ARMY!

    A DECADE OF DOMINANCE! +2

  4. #4
    Join Date
    Jun 2010
    Location
    Philadelphia PA
    Posts
    2,190

    Hello Mary, so many choices...

    Quote Originally Posted by MaryO View Post
    Hi Everyone,

    I live in an older home with hot water oil heat and big old iron radiators. I am in the process of getting estimates on converting to natural gas. My current boiler is pretty new (8 years).

    Two people who have come by have told me that I should just convert the burner given the age of the boiler.
    On the face of it, sounds like a good idea But at what cost vs new unit?
    Further, one person told me that a high efficiency boiler has lots of condensation geezs < I hope that condensing boiler condeses, that's why its called condensing that would be a major service nightmare with iron radiators and pipes.
    Here is the real issue, are your rads in excess of what you really need. If you can operate the condesing boileer at a temp that uses the low temp (less than 180 degrees 0 and met the needs of your home then condensing boiler MAY BE A GOOD IDEA but if you need the 180 degree wter a good deal of the season then NO IT WON"T ( make sense for condensing)

    The man identifying where the gas meter would go also told me that I should do a conversion, and that folks would try to sell me a new boiler when it wasn't necessary.Ceertsainly a good chance of this being true

    So, a third guy was just out this morning who told me that I would be very disappointed in the savings if I didn't go with a new high-efficiency boiler. He told me that the condensation would not be an issue. He also said that converting it would be very inefficient -- lots less than it is currently with oil -- like it would end up being around 70%. The boiler doesn't care what hydro carbon you decide to burn, so I am having some trouble with his remark

    If anyone can give me any insight on this, I would be very grateful. Thanks so much!

    Kind regards,

    Mary
    There is nothing as good as those high mass rads. Keep them as long as you can. Also the opportunity for reset ( lower ) water temps that match the load is an area that needs a contractor who understands BOILER PROTECTION ( how to avoid condensing with a boiler that is not supposed to condense

    Good luck
    You have got to learn from other people's mistakes! Because God knows you don't live long enough to make them all yourself !!!!!!!!

  5. #5
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,765
    Heatseeker

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