insulating basement hot water pipes

Discussion in 'HVAC Heating & Cooling' started by Bob in Maine, Jun 30, 2008.

  1. Bob in Maine

    Bob in Maine New Member

    Messages:
    14
    A basic question.

    If I insulate the hot water heating pipes that run from my boiler in the basement to radiators on the floor above, I'll reduce the amount of heat lost from the pipes to the cold basement air.

    However, by doing this, I'm effectively removing the main heat source from my basement in the winter which might lead to frozen domestic water pipes or colder floors above.

    What's the common wisdom about insulating basment heating pipes?
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,937
    Location:
    New England
    Depends on if you want the basement warmer...
  3. jimbo

    jimbo Plumber

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    8,997
    Location:
    San Diego
    Where I grew up in MA, we had single pipe steam heat. The pipes running around the basement, just under the joists, were somewhat insulated, but a lot of the joints were not, and some pipes that were replaced over the years with boiler replacements were not. As a result, the basement temp was comfortable all winter! It was not a finished basement, but the laundry was down there, as well as our "toys"....train sets, ping pong, etc.

    I am sure that from an energy standpoint, it did not make sense. But gasoline was 22 cents a gallon, and the NG was also cheap. And the celing was not insulated, so I think a lot of heat just rose up to the living area of the house, and contributed to a nice even comfy warmth up there!
  4. Bill Arden

    Bill Arden Computer Programmer

    Messages:
    584
    Location:
    MN, USA
    1. How deep is the frost line?
    If you insulate around the basement border and seal it up any air leaks, the basement will automatically keep it at the ground temperature.

    This will also reduce heat loss from the heated pipes by trapping the heat they release into the basement.
  5. Bob in Maine

    Bob in Maine New Member

    Messages:
    14
    The frost depth here is 48" inches below grade.

    The framed floor sits about 2'-6' above grade, so when I stand in the basement, there's about 1'-8" of concrete above grade and another 10" or so of framing above that. The basement floor is about 7'-6" below the framed floor above.

    Unfortunately, since the frost line is deep here, nearly all of the soil outside my foundation wall is is subject to freezing temperatures

    The basement is unfinished, so I don't care how warm it stays, just as long as the pipes don't freeze.

    I'm nervous about insulating the inside of the basement walls for fear of trapping moisture and growing mold. We're pretty close to sea level out here, and the basement tends to be damp.

    I agree that sealing all potential air leaks in the basement is a good idea.

    My gut feeling is that if I insulate the heating pipes in the basement, enough heat from the story floor above will transfer to the basement (through the pine sub-floor and hardwood finish floor) to keep the water pipes in the basement from freezing, but I'm still not completely sold.
  6. D.Smith

    D.Smith New Member

    Messages:
    63
    Location:
    Georgia
    I would think for the most part you would be ok. I remember even in a craw space it would stay above freezing for most of the winters.


    For piece of mind you can place a heater set at a 33 degrees in bsmt to protect against freezing.
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,529
    Location:
    Cave Creek, Arizona
    heat

    The heat you are "losing" in the basement is helping to heat the upper level's floor, so it is not really "lost". If you remove that source of heat, the upstairs radiation will have to operate longer to compensate for it, so your total energy bill may not change, and you will lose the warmer floor and livable basement.
  8. Bob in Maine

    Bob in Maine New Member

    Messages:
    14
    Thanks for the information.

    Very interesting thoughts.
  9. mortimer

    mortimer New Member

    Messages:
    12
    I don't think that I would insulate the pipes. While the cost should not be an issue, you might a fixing a something that isn't broken.

    As an aside, I live in a walk out basement and use a pellet stove to keep it well above freezing.
  10. gvernt

    gvernt New Member

    Messages:
    2
    I Have Insulated my Pipes

    A few years ago I insulated my pipes and noticed a drop in the basement temperature. I have three separate hot water zones and once I insulated the pipes the temperature in the basement dropped a few degrees. The coldest I've seen is 58F in the basement and I live in the northern part of New Jersey. My basement is made of cider block walls (1000 sq ft) and I would say the upper two rows of blocks are exposed to the air outside and the remaining part of the basement is underground. My basement ceiling is uninsulated but I am currently installing a new green insulation on the ceiling which is called UltraTouch (recycle jeans), so my basement temperature should drop futher. I'm not really worried about the pipes freezing since my boiler, water heater and dryer give off enough heat. But let see what happenes this winter.
  11. xroad

    xroad New Member

    Messages:
    113
    I am in central Jersey, same situation. Smaller house, 625 sq ft basement. As long as the air temperature is above the temperature of the basement concrete walls and floor, there will be heat loss to them. The greater the difference in temperature, the greater the loss. I insulated the pipes, the air temp is lowered. The risk of pipe freezing is often not colder air temperature but more of air leak. The pipe near the perimeter of the basement or near a window frame run the risk of an air leak stream of cold blast like a blow torch. It is important to seal all air leaks. Insulatig the walls and floor is another big job. Issues of mold is a concern for me as well. Insulation may cause problem. There is also heat loss from the first floor to the basement ceiling. I never insulate the ceiling because I was afraid of the fibeglass flying around. The chopped old denim jeans is a very good idea. I think I will go that route. It should make the floor in the first floor much more comfortable and the basement even colder. Not insulating the hot pipe will make your floor warm but at a cost. I do not believe heating space I am not using. Put in a few electric heating dish in the basement. When you go down there, you will need to turn on the light. Wire the heat dish to turn on with the light.
    Last edited: Oct 12, 2008
  12. jimbo

    jimbo Plumber

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    8,997
    Location:
    San Diego
    Generally, heat does not radiate DOWN.
  13. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,937
    Location:
    New England
    Heat radiates equally in all directions...convection moves the hotter air up. If heat only radiated up, we'd be in a very bad state without the sun...which way is up anyways? Gravity doesn't affect radiation...
  14. xroad

    xroad New Member

    Messages:
    113
    Heat radiates from hot to cold.
  15. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,937
    Location:
    New England
    If you want to get technical, there is no such thing as cold...it is the absence of heat. Energy levels move to attain equilibrium, all things being equal.
  16. maintenanceguy

    maintenanceguy In the Trades

    Messages:
    107
    Location:
    Pennsylvania
    No, heat will be transferred from something hotter to something cooler (law of entropy) but heat RADIATES in all directions equally and is not aware of the temperature of the target.
  17. xroad

    xroad New Member

    Messages:
    113
    You are correct, I stand corected. I feel so old, HS and college physics was such a distant past.
  18. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    If you don't insulate the basement walls then some of the heat given off by the piping and the boiler is lost to the ground. There are charts somewhere that graph all this. Very confusing but the gist of it is that it is marginally better to insulate the pipes than not. Naturally it would be better to insulate the pipes and the foundation. The energy code requires basement floors to be insulated now also so if you keep the pipes bare in that case you get even more heat migration through the foundation.

    I like to insulate all hydronic piping because I want as much of that heat from the boiler, into the baseboard as possible so that I can maintain a set delta t. This makes the boiler and system more efficient. Yes we're talking a few bucks not a fortune but every little bit helps.
  19. crater

    crater New Member

    Messages:
    49
    Isn't a controlled or conditioned space better than a none conditioned space?

    opinion of a Certified Green Professional (me)

    Insulate your pipes for max efficiency and then tend to the space requirements by conditioning the space(basement)

    Also repair air leakage to maximize the efficiency of the space. Types of Air handlers should be able to take care of the humidity(moisture) problem then insulate walls with closed cell styrene insul board if still Leary of moisture.

    Thinking of heat loss in this way as "beneficial radiant heat" is crazy.
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