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  1. #1
    Join Date
    Feb 2009
    Posts
    1

    Default hot water baseboard questions

    I know nothing about this(it will soon be obvious). 1978 construction, 1100sqft ranch, hot water baseboard heat. Works ok (rooms farthest away remain cool) but am replacing for better efficiency. Will replace main heating unit (boiler) but wondering if there is need to replace any of baseboard piping, etc. Would really appreciate any advice by those of you who have nothing to gain monetarily by sharing your knowledge.Thanks

  2. #2
    Join Date
    Feb 2008
    Posts
    556

    Default Re: hot water baseboard questions

    meanch:

    Best procedure would be to get at least 4 to 6 estimates from local oil dealers & heating contractors---the cost of the equipment and brand name choice will vary widely among the estimates----this would be the time to ask the installers to check out your system & perhaps make minor modifications to your current baseboard/piping distribution system.

    Wait until the spring or early summer to do the install when the techs are not so busy & will take the time to do a good job.

    Since you are having problems with less heat in some of the far baseboards---this could be caused by a) insufficient length of the baseboard in that particular room, or b) a series loop piping arrangement where the hot water from the boiler goes in a large circle from one baseboard to the next, & the water cools off as it reaches the rooms on the return end before returning to the boiler---often the boiler main hot water supply is split at the boiler & 2 separate hot water supplies are pumped in opposite directions around the cellar thu the baseboards & meet at a center position & then a 1 1/4" main heat return is run down the center of the cellar as a return of the cooled water back to the boiler---read the heating help.com site on piping arrangements used & diagrams--click onto loop hot water piping & diverter tee piping to see how various piping arrangements affect heating patterns in baseboard---read further down to see the diagrams for "splitting the piping loop"---diverter tee arrangements allow each baseboard section or radiator to be partially shut off to control heat in each room, but is less important in smaller homes.

    Sometimes a 2 zone system is installed on the same boiler if bedrooms are upstairs, or more heat control of certain rooms is needed---each zone has its own thermostat.

    Check the square footage of each room & the # of feet of baseboard to make sure each room has enough---each foot of baseboard puts out 580 btu/ft/hr--if you take the square footage of the room, multiply by a heat factor of 40 you will get the heat load of the room (assuming 8' ceilings).

    Thus, a room 15 X 15 = 225 sq.ft. X 40 (heat factor) = 9000 btu/hr heat needed to keep the room warm---if the room has 12' of baseboard: 580 X 12 = 6960 btu/hr heat output, it would mean the room has inadequate baseboard (should be 16' or so)---a lot also has to do with making sure you have adequate exterior wall insulation (R19) and attic insulation (R40)--this can be easily blown in NOW for $400 before you order the new boiler---this will allow you to order a smaller boiler & save $$$---also make sure you have no drafty windows & have storm windows or double pane units.

    Double the heat factor for any bathroom--bathrooms are hard to heat & because of cramped space, long runs of baseboard, or even a radiator are impractical---there are hot water KICKSPACE HEATERS with an elec. fan that fit under a cabinet, etc.---2 or 3 feet of baseboard are sometimes double or triple stacked on top of each other (plumbing supply house) or towel warmer rads are installed---thus for a bathroom of 10' X 10' = 100 sq.ft. X 80 (heat factor) = 8000 btu/hour to heat the bathroom.

    Another remedy would be to install a few more feet of baseboard in the problem rooms or perhaps add a cast iron radiator, which retains heat longer---cast iron rads are best bought from a salvage yard, demolition co. or used plumbing supply & sandblasted & painted at an auto body shop--cast iron rads are always placed direcly in front of a window to offset cold drafts & improve heat circulation.

    The links below have a list of recommended boiler brands----condensing, stainless steel variable output boilers with outdoor reset with an efficiency of 95%, or 3-pass cast iron boilers with an efficiency of 88% are recommended over standard cast iron boilers.

    Radiant floor heat would be another option, at additional initial cost due to installation of staple-up PEX plastic tubing between the floor joists & would require someone knowledgeale in this type of installation---if you intend to stay in the house over 5 years, this should be considered, as it will save fuel $$$ over the long run.

    A 40 gallon indirect-fired hot water heater (if you don't already have one) is strongly recommended over a separate gas or oil hwh---these run off the boiler & burn no additional fuel.

    http://advice.thisoldhouse.com/showthread.php?t=3820
    http://advice.thisoldhouse.com/showthread.php?t=5571
    http://advice.thisoldhouse.com/showthread.php?t=1639
    http://www.heatinghelp.com/heating_qa.cfm
    Last edited by NashuaTech; 02-14-2009 at 07:23 PM.

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