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heat loss calculators

Eric_51
Eric_51 Member Posts: 30
Are the programs that bad, going by what i find online my sons room needs 6000btu's.  Right now it is 10 out side and its hot in his room with the heat off and the 360 going.

Comments

  • Gordy
    Gordy Member Posts: 9,514
    Garbage in

    Garbage out. If the information requested is in accurate then the calculation will be.



    How big is your sons room?

    How many exterior walls?

    How many windows? Size, type?

    What kind of heat?

    What inside temp, and outside design temp did you use?

    Do you know the outdoor design temp for your area?



    6000 btus sounds about right for an average size bedroom with one or two exterior walls.....depends.
  • Eric_51
    Eric_51 Member Posts: 30
    edited February 2014
    more info

    so for the little info, had to get my son at school. The room is 10x12x10 with one window that's 12 sf the out side wall is 12f long. Its made of wood 5 inches thick with 1 inch foil covered foam on the inside. it is over a crawl space with no insulation, above it is covered by half roof half room so i figured  normal roof. the heat is hot water baseboard thats turned off, the system is hacked bad from freezing many times before i bought it thats why im  cheaking numbers. i was wanting to put in 3 feet of new bb.
  • Gordy
    Gordy Member Posts: 9,514
    No heat

    To room now and it over heats?



    Why did piping for base board freeze?



    Is the crawl space vented, or conditioned?



    Does piping for base board exist on

    The crawl space?
  • Eric_51
    Eric_51 Member Posts: 30
    more info

    the house set empty off and on for years, the crawl space is cloed to the out side. the walls are 2 foot  stone. the pipes run along the walls but im going to move them to the crawl space. im heating my house with a wood stove in the basement, it uses 2 1/2 cords a year. My water pipes are in the crawl space and they don't freeze even at -20. I want to put new bb in the house with a new furnace with id hw, 4 zones in the bb with valves. when i us the heat los calculators my furnace size should be 48000 btus, going by the sf method i need 150000 btus wow..
  • Ironman
    Ironman Member Posts: 6,365
    SF Method?

    Please explain the square foot method. I've been doing load calcs for about 35 years and I've never seen that in any manual or program.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Gordy
    Gordy Member Posts: 9,514
    Agreed

    If you are talking about x amount of btus per square foot then that's why it's such a high number. That's called thumbing it in.......a no no.
  • Eric_51
    Eric_51 Member Posts: 30
    sf method

    take the sf x conversion factor for house style and climate zone. for me it was 1900x1.25 (old house) x65 for northern pa extreme = 150000 btu also translates to a 4 ton ac unit. made my hvac Friend go ????? That's why i asked the question.
  • Eric_51
    Eric_51 Member Posts: 30
    new boiler

    I want to put in a Biasi b-3 with armtrol 40 gal idhw on own circulator and 4 zone valves in the house on bb. the zones i want to use a variable speed pump. the boiler will have outside temp reset and a controller that can handle everything. i just want to get info on all this stuff before i do it. A lot of $$ to be wrong..
  • Ironman
    Ironman Member Posts: 6,365
    Hee Haw Math!

    That reminds me of Archie Cambell proving that 2+2= 22 on HeeHaw.



    Your square foot method means your house needs almost 79 btu's per square foot at design temp.



    I've worked with some of the oldest, most leaky houses in the country and I've never seen one that came anywhere near that. It would be rare to find one that needs half that unless the design temp was -20 below.



    This "method" was probably thought up by the same guy that said you could size A/C by dividing the number of windows on a house by the number of doors. Or guy that drove by at ten mph and divided how many seconds it took to pass the house in to that to size the A/C.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Gordy
    Gordy Member Posts: 9,514
    Direct answer

    Start with a room by room heat loss.



    This will tell you how many feet of base board needed for the style you choose.

    Size your base board so you can use lower water temps if wall space allows for this. This is not so important since you are not installing a modulating condensing boiler.



    Most base board manufactures have output charts for various water temps.



    No gas available to your property?
  • Eric_51
    Eric_51 Member Posts: 30
    slat fin

    That works nice, my calculations are close. I have to much in some not enough in others, but the heat loss numbers are right for the rooms. my numbers changed on the bb. I'll add some more to the rooms that i can, those rooms are only short by a couple of feet each.
  • SWEI
    SWEI Member Posts: 7,356
    edited February 2014
    I want to put new bb in the house

    Really?  There are so many wonderful options that work better.  Do yourself a favor and design the system for a lower water temperature, ditch the zones, and install thermostatic radiator valves (TRVs) on each radiator.



    www.runtalnorthamerica.com

    www.mysoncomfort.com



    Edit:  See you are looking at a Biasi B-3, which seems to indicate you are planning to use oil.  Assuming you have no NG availability, and looking at the volatility of both fuel oil and LPG markets, I'd give some serious consideration to a VRF air source heat pump.
  • Gordy
    Gordy Member Posts: 9,514
    I agree

    If your going to install all new elements take SWEI's advice. I find radiators a bit more elegant.



    Definitely look at your fuel choices http://www.eia.gov/tools/faqs/heatcalc.xls



    Check your electric rates it may be a better choice. Is cooling an option that need be addressed?
  • Eric_51
    Eric_51 Member Posts: 30
    bb

    Im only changing  some rooms, others have enough or were changed years ago. If i was doing a remodel i would think about the radiators look cool. as for cooling id need wall mount units becouse there is no place for ducts.

    just to do bb is a hassel for the house has a an out side beam of 18x18
  • Eric_51
    Eric_51 Member Posts: 30
    fuel

    The only two realistic choices is oil or propane.I'm already set for oil with the tank inside, for propane id want the tank buried but then that's a lot of work and extra expense. i have looked into Geo but that would kill my small basement with all the stuff needed, the basement is only10x18 with freezer washer and dryer water softener stairs water tank pump ....
  • icesailor
    icesailor Member Posts: 7,265
    Calculating Changes:

    If you are going to do anything like add, subtract, multiply or divide. do as complete and accurate whole house calculation of heat loss as you can. Then, measure ALL installed radiation on a room by room basis. Then, take each heated room and write the heat loss and installed radiation for each individual room on a sheet of paper. Then, look for some constant that someone may have used to come up with what they installed. You may find that there is no constant that you can use to get a balance. There just isn't one. Someone used the pencil at arms length method. Anything you add, put it on a different zone. Otherwise, the space will be too hot or too cold. Seldom just right and in balance with the rest of the house.

    That's what the make zone valves for.
  • SWEI
    SWEI Member Posts: 7,356
    Realistic choices

    Daikin Altherma?



    You can install radiators where you replace baseboard.  If you size them for 140ºF water and then add a TRV, they will behave well at the higher temps you need for the existing baseboard.  As you replace more and more of the BB, you can turn down the system temp and raise your efficiency.
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