The Wall
Forum / Gas Heating / Mr.
  • Post a Reply to this Thread

    Mr. (6 Posts)

  • Rozie Rozie @ 9:03 AM
    Contact this user

    Boiler sizing question

    I live in Boston, MA and am planning to covert from oil to gas. Have had three contractors come in and am concerned they are recommending over-sized boilers. The local utility offers deep discounts and rebates on the Burnham Alpine line. The utility offers the 80, 105 and 150 Kbtu models.

    Each contractor has recommended the 105, but I'm still concerned they may be over-sizing since over-sizing appears to be a common problem.

    None of the contractors I've talked to has been wiling to do a Manual J calculation. Am I asking the wrong question? Should I be asking simply for a "heat-loss" calculation? One of the three did measure the radiators and count sections. The other two just eye-balled the house. It's a 1200 sf, single-family home built in 1926, frame construction. Walls had insulation blown in maybe 20 years ago; windows are original windows but with storms.

    How do I figure out if the Alpine 105 is oversized for my house?

    Thanks!
    This post was edited by an admin on May 23, 2013 9:22 AM.
  • Robert O'Brien Robert O'Brien @ 9:15 AM
    Contact this user

    Heat Loss

    Do it yourself.app is here: http://www.slantfin.com/index.php/homeowners/ipadapp
    Not a huge penalty going from 80 to 105 with an Alpine,the bottom end is 16K on the 80 and 21K on the 105. Ever wonder why Nat Grid offers rebates on Burnham and no one else?
  • Chris Chris @ 5:01 PM
    Contact this user

    You Cannot Over Size

    A modulating condensing boiler on the top end modulation rate. It's the low end where the problem lies. The boiler will only go to high fire when the demand is there. Think about it the 80 and 105 are the same HX..
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • heatpro02920 heatpro02920 @ 6:56 AM
    Contact this user

    Do yourself a favor...

    And keep looking for a contractor, you want a heat loss done, you want a properly sized boiler, I personally wouldn't go alpine, even with the discounts, check into the Triangle Tube Prestige Solo 60 {from what you have said about your home, I'm guessing that's going to be your guy}...

    You will still get the rebates, but have {IMO} a much better machine...

    There are plenty of good contractors in your area, just have to weed through to find the rite one...

    Another thing to think about is a conventional gas boiler, since you will have such a low heat loss, poke around with the math and figure out what a mod/con is going to save you over its expected life. Then make a better educated decision... I tend to recommend mod/cons for people that spend enough on energy to warrant the added expense.. If you are only spending $1200 a year on fuel {gas not oil} and the mod con is going to save you 15% over a properly installed conventional boiler that's only $180 a year, so after you factor in the added service expense, shorter life cycle, more expensive service and installation, it may not be the best idea to go high efficiency... Just food for thought...
  • jonny88 jonny88 @ 9:18 AM
    Contact this user

    Great point

    Heatpro makes a great point.I know with Nat Grid they offer rebates on Burnham.If you are not 100% on the Alpine try the ES2 with the Alliance indirect put an outdoor reset on top of that and you should have a highly competitive system.
  • gennady gennady @ 10:08 PM
    Contact this user

    Boiler

    Standard efficiency boilers are thing of the past. They are sized to the worst case scenario, and this worst case happens only few days a year. The rest of the time standard efficiency boilers just wasting fuel. Contemporary modulating boilers matching load exactly for any given moment when set up properly. Proper installation is essential but setting boiler properly is even more important. 15% savings is a nonsense number. If there is no saving of 70% or more on oil to gas conversion with mod con then you can ask installer for refund. He did not do his job.
    Gennady Tsakh

    Absolute Mechanical Co. Inc.
    www.AbsoluteMechanicalCoInc.com
  •  
Post a Reply to this Thread