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In need of an education on radiant panels

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by Fred61, Sep 25, 2012.

  1. Fred61

    Fred61 Minister of Fire

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    A friend of mine is currently building a new house in New Hampshire. Knowing that I had installed radiant, he asked me about insulation under the basement slab and any other actions he should take to reduce losses, etc. I was able to help him with that. He then mentioned that he would be installing baseboard heat on the main floor. Knowing that he would then need to maintain a higher boiler temperature, I suggested that he also install radiant on the main floor in order to keep his boiler temperature lower. He went back to his heating contractor (who I believe is still living in the last century) and suggested that he wanted radiant on the main floor.
    After balking at the suggestion, the contractor agreed and said he would quote for radiant on the main floor but he would still need to keep the boiler temperature up because there is a small bedroom suite on a second level (that I was unaware of) and he would need baseboard up there.
    Having read several posts about radiant panel emmiters on this forum, I had come away with the assumption that these emmitters also used lower temperater water. When my friend went back to his contractor he was told that radiant panels needed 180* water to function. He also presented a quote of $30,000.00 for the heating claiming that the installation of radiant panels brought up the price significantly.

    So my question is: Will radiant panels function at the lower temperatures typically used for radiant floor?
    Also: Does anyone have any suggestions on which ones to use and which are the most asthetically pleasing to the eye. Also, The best source to procure these units?
    I did some searching and found several that look quite different from each other. Is there a difference in the way they function?

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  2. Bob Rohr

    Bob Rohr Minister of Fire

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    Sure you can use lower temperature emitters. Most of the manufacturers now rate their products down to 120F supply! Heating Edge, SlantFin, Jaga are some brands. Most any brand of panel rad has a de-rate chart or factor. Remember with panel rads the size goes up about 40% when going from 180-F supply to 140F or lower. There is no "free lunch" lower temperatures require more HX surface area.

    The goal of the hydronics industry is to be able to heat any building with 120F or lower. This drives solar, heat pump, condensing efficiencies and extends wood boiler buffer tanks
  3. Como

    Como Minister of Fire

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    I use radiators. Mine are sized to use 140f heat
  4. Fred61

    Fred61 Minister of Fire

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    I'd use radiators in a minute but no-one will ever convince my buddy's wife to install them. I happened to be in the basement of an old commercial building in a town south of here and there was a wall covered with the most beautiful design cast iron radiators I had ever seen. To me, they were a work of art. If I ever get another chance to get in there I'll photograph them and post them here.
  5. heaterman

    heaterman Minister of Fire

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    He can still use BB on the second level. Just install more lineal feet to make up for the lowered output at reduced water temps. I can't believe how many contractors I hear saying "baseboard doesn't work unless it's it has 180* water in it".
  6. willyswagon

    willyswagon Burning Hunk

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    It's like the contractors that say "Don't bother insulating your furnace room." or "Don't bother insulating your heating pipes between each radiator, that heat is just lost to the house anyway"

    Ya but I don't live amongst the floor joists between my basement ceiling and main floor surface, so why would I bother heating that area.

    As North Americans we have a long way to go to make our houses more efficient
  7. Como

    Como Minister of Fire

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    Houses too large is the main problem, which makes forced air more practical, well with cheap energy anyway.

    If you look outside the US radiators come in an enormous number of designs.
  8. Gasifier

    Gasifier Minister of Fire

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    We have a friend who is a heating contractor. Younger guy who keeps up and tries to educate his customers without pushing things. He does some geothermal, some solar. He likes the radiant panels and says if you are building new, radiant in floor or radiant panels is the way to go. He did the radiant in my concrete garage floor. I love that. I have wondered if it would make sense economically to replace my baseboard some year with radiant panels. I don't know if I would save enough money over the years though. I doubt it.

    I like the older, large radiators. My brother has a very large, old house. It has to be over 4500 sq. ft. It has a large radiator in just about every room. Talk about nice, slow, even, steady heat. He use to heat it with just a natural gas boiler. Until he could no longer afford it. Now he has a large wood stove on the main floor and has cut his heating cost in half. I am slowly trying to convince him to go with a wood burning gassification boiler and further cut his cost. He said he may in the future.
  9. kopeck

    kopeck Minister of Fire

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    When I sized the BB for the room I'm working on I just looked at the chart the manufacture provided and figured what I needed based on the temp water I planned on running. It' all right there...

    I had considerably more trouble figuring out heat loss but once I had that down sizing the BB was super easy.

    K

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