An idea to prevent pipes from freezing in crawl space.

We have a summer home on the NJ coast that sits on top of an unheated crawl space, (2' high). There are 4 vents into the crawl space. The copper plumbing pipes run throught the crawl space. No heating duct work at all is in the crawl space.
We have NEVER kept the house open in the winter, (i.e. water off, pipes drained, etc.). This winter we will need to keep the house open. I have been making several modifications to prevent the water pipes from freezing in the crawl space.
So far I have installed a new gravity flow wall furnace, (not the best for keeping floors warm), and insulated all water pipes in the crawl space. I plan on keeping the house temperature at 65 degrees minimum to hope that the hard wood floors will transmit enough heat to the crawl space to prevent pipes from freezing. I will also close off the vents once the cold weather approaches.
** HERE IS MY NEXT THOUGHT: I was thinking about installing a bathroom ventillation fan on the main level in the living room and venting it through the floor into the crawl space below. I could place this fan on a timer so that it goes on sporadically throughout the day and night to "push" some additional living space heat into the crawl space. I don't think that this loss of room heat would be a waste as the floor would benefit from the heat in the crawl space.
Any thoughts, ideas, or additional comments are appreciated.
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It sounds like it would be a losing battle. First off, heat from the wall furnace will not radiate through the wood floor to the crawl space below, at least not enough to make an impact of keeping the crawl space above freezing during a period of cold weather. Remember, hot air rises. And I think the bathroom fan idea would be a waste too. A good alternative is to use heat tape around the pipes. Or to install some kind of electric baseboard in the crawl space with a T-stat set at about 45-50 degrees. With a 2 foot high crawl space, it should not take that much energy to heat. What is the square footage of the wall space?
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I wouldn't want to place any type of electrical heating in the crawl space as this is a shore community and frequently prone to flooding.
The heat tape is an idea I thought about for quite some time but have read many horror stories following either improper installation and/or fire following break down of wire insulation over time.
The house is roughly 25' square with a two block crawl space.
I understand that heat rises, but I also add that heat would travel from a warmer region to a colder one as well.
Again, why exactly do you feel the bathroom fan idea is a waste?
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As you say you insulated the pipe(s) in the crawlspace I doubt the fan pumping in heated room air will have much effect. Any air leakage at all would negate the bit of warm air you blow in.
If you can,....insulate UNDER the pipes and allow the floor to transfer heat where it gets trapped around the pipes. or use a pipe wrap heater cable, that has a thermostat to kick in if the pipes get down to 32 degrees.
But the best solution is just to get the pipes out of ANY unheated areas, and/or drain them each time you leave.
As power failures do happen or the furnace could break.
AMUN
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You can fix up a constantly-circulating water current and small pump. You will need to put a return pipe and small valve. It needs some thought but it can be done. I was going to do that on my old house but I moved just before winter (good luck to the new owners!)
Dean
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Sometimes the "best solution" isn't possible as in this case unfortunately.
If the crawl space is sealed to the outside, (as best as possible), the fan would not make any appreciable difference?
Bringing the pipes into the heated area would be ideal, however, placing insulation underneath or boxing them into to the floor above really isn't practical or completely possible to accomplish.
The pipe heating cable makes me very nervous as I stated earlier.
Incidentally, there will be someone living there all winter so the house will not be vacant.
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It might. But if it was sealed that tight, you would get more benefit from the ground temp being about 55 degrees anyway. And keeping out the frost alone.
Sounds like you should be considering insulating/sealing the walls in the crawlspace to keep out the cold to start with.

see above suggestion to just insulate the whole crawlspace

That makes it a different story, if people are now going to be there steadily year round. All the more reason to think about insulating the whole building rather than just one or two pipes.
AMUN
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It would also be blowing in moist air and possibly creating a mold problem.

Insulating hte pipe themselves can be counter productive. While it slows the loss of heat from the water in t he piopes, it will alsway try t reach equallibrium witht he ambine air. Insulation will also prevern any heat from the flooring to reach the pipes to prevent freezing. Boxing them in or insulating the space below makes much more sense to get the heat to where it is needed.

Agree, but there may be some sections where that is best and there is no physical contqct tot he structure.

That helps immensly. What that person can do in freezing weather is periodicly open the faucet to move the colder water out and replace wiht with water at the temperature of it in the ground. Leaving a trickle of flow helps also but adds to the cost. I know of some commnities along the shore where water is expensive but sewer is VERY expensive do to the pumping needed at near sea level to move it.

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The cost of water/sewer is not a factor as we are not metered, (hot water of course cost money).
The fan would be delivering warmer/dryer interior heated air to a colder damper basement. I don't understand why mold would be an issue.
Insulating the interior walls of the crawl space with insulating boards probably would help to "seal-off" the crawl space from the outside environment. Maybe thats something I should consider. I guess I would just need to cut them to size and use a "liquid nail" type of product to secure them to the foundation, correct?
The person living in the house will let the distant most faucet slowly run during intense cold spells as well as leave cabinet doors under sinks open.
I have also read about placing 100 watt lamps near plumbing on timers to add additional warmth.
All suggestions are appreaciated.
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Uh,.....and you afraid of the heated pipe tapes/wraps ????
AMUN
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Have you ever heard of a fire originating from a foundation vent?
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Not yet. But if you let us know the town you're working in, we'll be sure to keep an eye on the local newspapers. <g>
AMUN
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I don't get it. You're afraid of heat tape but want to use light bulbs? Is the person living in this cabin is unlikely to notice that the level of water outside means that the crawl space is flooded? When the crawl space floods doesn't that mean that it is too warm for the pipes to freeze? What's wrong with heat tape?
Dave M.
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I actually never stated that I wanted to use 100 watt lamps. It was just another recommendation that I read about.
I truthfully don't think there is anything wrong with properly installed and regularly checked and replaced heat tape. Regular inspection of the heat tape in this crawl space would be a cumbersome, dirty project that I would like to avoid.
I would much rather not get involved with bringing any electrical current into the crawl space if possible.
In the past there have been several houses burn down from electrical type of events. From what I was told the salt air over time will cause a corrosion to develop between copper splices in electical boxes. Over time with increased corrosion you now get arcing of current rather than direct connections. Arcing generates heat and goodbye house.
Thus.....I'd rather keep electric connections out of the crawl.
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On Wed, 21 Sep 2005 17:41:25 GMT, "David Martel"

Heat tape on a GFI outlet on an AFI circut, that should address any rational fears.
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i use one of those small 10x10 electric room box heaters with a fan in my crawl space.i keep it on low and do seal off the vents to the crawlspace very tight. those heat tapes really arent as dangerous as you think, just replace it every 4-5 years or so. lucas
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You might airseal and insulate the crawl space and install $12 automatic foundation vents with louvers that only open on warm days.
Nick
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I've thought about installing those automatic foundation vents but was uncertain as to how difficult installation would be.
The current vents in my crawl space are nothing more than one cinder block placed "sideways" to allow the openings to be exposed from outside to inside.
I guess I would need to purchase a small circular saw with masonary blade to cut out these vent blocks.
It appears like the foundation vents get mounted from the sides by some type of fastening method.
Ever install any? If so, exactly how difficult a process.
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I had these retrofitted on my house. You make an appropriately sized hole, Slide in the vent and tighten two screws, The screws press against the sides of the hole and secure the vent by friction. I'm uncomfortable with the notion of insulating your crawl space. Since this space regularly floods the insulation will wick up moisture and hold it against your framing.
Dave M.
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