Asked on Jan 07, 2014

Why Would a Hot Water Pipe Freeze but the Cold Water Pips Didn't?

Annette C
by Annette C
So I wake up Yesterday & it's sooooooo Cold in the house, the thermostat reads 52' OMG, are there door's or windows open? No... No frost on the ground that I can see, but so cold I can almost see my breath, lol Go to make coffee, turn the hot water tap... Air.... O no, not again, did I for get to pay the water bill?
Turn the cold water tap, nope there's water coming from that tap, ice water..... Go to the hall bathroom & hit the hot water tap on the tub, it's the first line off the hot water heater surly it will work... Nothing.... Cold water works tho, the sink, the same no hot water tap but the cold taps work... Go to the Master bath, nothing no hot or cold.... Hmmmmm
Thinking the pipes froze..... I hope....
Weirder yet is that if we turn on the hot taps in the other parts of the house, and then just the cold water tap in the Kitchen; water comes out the hot taps in other rooms but it's cold water, lol
Not so much a question as one of the many Humorous, not so funny happenings in my lovely & so comedic life in my 65 year old pier beam home. Thank fully this morning was much much warmer inside my home Tho I still have no hot water or water in the back (shady side) of the house....
I hope you all get a giggle I'm still laughing at the weirdness of it all & hoping I don't have to call a plumber...
65 years young
  28 answers
  • It is because that is the line that go cold enough to freeze, possibly because it is missing insulation at a corner or... As I am not in a mood to retype all the steps for an easy fix...
    • Annette C Annette C on Jan 08, 2014
      @SLS Construction & Building Solutions I know the basic reason is none of the pipes are insulated properly, Just thought it was odd that the hot side froze but not the cold. My guess was that more of cold pip is under the ground with pressure from the city & the hot is completely exposed. It took two days to defrost & what do you know there's a burst pip in the back half of the house, the shady side. Was really hoping that wouldn't happen but am not surprised.
  • Sorry it burst & I catch the irony but there is no difference between the two sides, except for what water they deliver - the hot side doesn't stay hot, it just delivers hot water when it is called for.
    • See 3 previous
    • Annette C Annette C on Jan 10, 2014
      @Elaine Simmons to be out-side with his father, lol He didn't get far & there was quite the crowd when I was able to get out (I'm sure all of market st heard my squeals), hubby had to add more coins to get the door open. They are the new public toilet's in San Francisco, very clean lol (well new in 2003)
  • Lynne Lynne on Jan 08, 2014
    really cute house..i live in a small house that has a basement you have to put a coat hat and gloves in the winter its so cold...i have copper pipe and i put heat tape on them it works, because the last few days in michigan wind chills have been 20 and 30 below. the tape is worth the investment
    • Annette C Annette C on Jan 08, 2014
      @Lynne I'm regretting not weather proofing, the real cold weather just kinda hit us all at once & I was not prepared, lol I still have summer curtains up, split level cafe style in my dining room & kitchen & light sheers on the floor to ceiling windows in my living room. Time to change things up before we freeze or the heating bill get's out of control, lol
  • Change of Art Change of Art on Jan 08, 2014
    Sorry about your pipes. I have no answers, but just wanted to agree with Lynne that your house is charming.
  • Lisa McDaniel Lisa McDaniel on Jan 08, 2014
    Speaking of pipes... I was taught/told that the closer to the water heater that a faucet is, the faster the water would get hot. Is this true, and if so, what would cause it to take 5 minutes ( or longer in winter ) to heat up when it is only 6-8 feet away? BTW, I love your house Annette !
    • @Lisa McDaniel - I got to ask, while the water heater might be close, how is the piping ran? Just because the water heater is close doesn't mean that the fixture closest to it, is in reality the closest. The next question is what type of water heater - if a tank or tankless
  • Annette C Annette C on Jan 08, 2014
    Thank you all for the complements on my home. My first post ever, not my prettiest yard photo but I didn't realize I would have to add a photo to post & it was the fist one I came to so i went with it. As soon as I can get out there with a power washer & paint brush I will take a nice photo, lol Tho as cold as it is in Shreveport right now I doubt I will make it out there any time soon. I love this old house & it's a lot larger than it looks from the curb too. Has a quricky lay out that keeps people guessing. She has all the original windows, moldings & hard wood floors. While it was nice when I bought her, my thought was to return her to what she would have looked like in 1948, that's how I happened upon this web sigh, looking for Ideas. My thought was I could get some feed back on the choices I will be making, see if I'm going in the right direction. I welcome all feed back, I like knowing others views & experiences in home improvement adventures. I'm not a pro & I don't really blog but I'm going to give it a try what's the worst that can happen, I already have burst pips & I replaced the roof & hot water tank last month, lol thanks every one I look foreword to many conversations to come
  • WilliamShreve WilliamShreve on Jan 08, 2014
    Hot water pipes freezing is not uncommon. My theory is you brush your teeth with cold water. Hot water pipes stay stagnant long enough to freeze.
  • Norman Ransom Norman Ransom on Jan 08, 2014
    It is an odd thing but hot water freezes faster than cold. One thing is that hot water lines are not hot except when running or you have a demand system that constantly circulates hot water. The second reason is hot water for most of us is softer than cold. I learned early in my refrigeration career to hook ice makers up to a hot water pipe rather than a cold and have fewer problems with the ice maker and faster cycling.
  • Elaine Simmons Elaine Simmons on Jan 09, 2014
    I read somewhere that when you freeze a bottle of water in your freezer, you should use lukewarm water because it will freeze faster so I think Norm is right.
  • Susan Stodola Susan Stodola on Jan 09, 2014
    Actually, it's BOILED water that freezes faster than 'regular' temp water......but not while the boiled water is still hot. (I know this because we did it as an experiment when we were home schooling.) The reason it freezes faster is boiling water forces the 'air' out and makes it more dense. The air 'bubbles' in 'regular' water work as insulation.....think double pane windows and how the expanse of air between the two pieces of glass work as insulation. I don't know how that computes to your hot water pipe except as some have suggested the water in the pipes was not hot at the time.
    • Annette C Annette C on Jan 10, 2014
      @Susan Stodola LOL one of the boys said that the hot water freezes faster too, but we weren't sure why, the fact that the air is expressed out makes since. I mean that's why we dress in layers, so that the air in the void will become worm. love trivia
  • Sharyn Diaz Sharyn Diaz on Jan 09, 2014
    Known as the Mpemba effect, water behaves unlike most other liquids by freezing into a solid more rapidly from a heated state than from room temperature. Read more:
  • Susan Stodola Susan Stodola on Jan 09, 2014
    For future reference, Annette............not that you can necessarily predict when this will happen again...... we had a similar problem with plumbing running through a crawl space to the kitchen sink on an outside wall.........and here in Wisconsin it gets very cold and even colder wind chill...... .....we found......1) leaving the doors under our sink open helped.......2) leaving the faucet drip......doesn't have to be much.....1 drip per second worked for us........3) having a small fan hanging from the floor joists in the basement blowing into the crawl space where the plumbing was.......we have to be very pro-active to keep our pipes from freezing.
  • Val Val on Jan 09, 2014
    Pipes will not freeze at 52 degrees. Recommend checking into other possible reasons for this problem. Val
    • See 1 previous
    • Annette C Annette C on Jan 12, 2014
      @Judy not only that but there is nothing to protect pipes from the weather changes, the prior owners did the change from copper to PVCP & they did a poor job & only converted what was under the house, not what is in the walls so I have metal to plastic connections. I found some pipes in the same aria that this pipe split that where on the ground, not even covered up with anything. Others that are tacked to the sub-floor are not insulated & have no clear markings showing what they are running to. The water pipes that go to my washing machine are backwards, the cold tap is on the hot side. Buyer beware I guess. I suppose the wall texture over the wood cabinets, tile & wallpaper should have been my first clue. I believed they where first time flippers that where trying to pass the work off as pro. But Any DIY'er could see these people were clueless, the home has a solid form to work with and I've had few problems over all. I really love this place and will miss it when I move on to Washington.
  • Lisa McDaniel Lisa McDaniel on Jan 09, 2014
    SLS Construction & Building- The pipe is ran closest to it. I'm not sure what you mean by "what kind of water, tank or tankless". We get our water from our county. No well or anything like that.
    • Annette C Annette C on Jan 10, 2014
      @Lisa McDaniel there are a few new types of Hot water heaters these days, there are the traditional tanks that hold a number of gallons to heat & then distribute to the house, there are others that are installed in a water line themselves, to a central water line or to a specific water tap, those only heat the water as the water passes through & hold no water in a reserve.
  • Val Val on Jan 09, 2014
    Hi Judy, Oops, missed that rather important detail! Val
  • Val Val on Jan 09, 2014
    Hi Judy, Thank you for your information. Many factors will affect whether or not pipes will hold up in cold temperatures. Where we live we experience deep freezes as extreme as minus forty. Our pipes run under the house and into the basement. They have frozen only three times in eleven years, but never at minus -8C (17 F). In her post Annette mentioned inside temperature only. It would be interesting to know the following: What the outside temperature was, is there a basement, if not were the pipes properly buried, is there a gap in the insulation at ground level, is there pipe insulation in place, to mention a few. The third time our pipes froze I put insulation up against the wall between the joists in the ceiling. Turned out there was a 1/4" hole between the concrete foundation and the main floor framing boards, and that is where the frigid air was sneaking through to the water lines, so you just never know. Fortunately they have not frozen since. Hopefully Annette will be able to solve her pipe dilemma expediently and inexpensively. Val
    • Annette C Annette C on Jan 12, 2014
      @Val we only were without water for 3 1/2 days, lol It took 2 days to thaw, once we could see the split it was kinda clear what the problem was, no pressure to push water out of the hot water tank. (found 2 windows open 1/4 to 1/2 inch in the front & back of the house, nice breeze, didn't find until day 4 when complaining and saw the shears move) The outside temp was only 18' F when the pipe froze & oddly enough the next night was 14 but felt warmer in my home & no other pipes froze, tho we may have left the tap dripping farthest from the intake line. (before I found the windows) We have pier-beam, with 3 open sides & about 3 1/2 feet of dead air under the house, no insulation what so ever. Not even visqueen, lol My first thought was that spray foam, then I thought if there was a problem later I may have a harder time finding the leak if it was sealed in foam, so we found the pre-cut foam toobs. I have to say at this point the pre-cut foam reminded me of pool noodles & the pool noodles are longer & dirt cheap, So I went back to pool noodles & cut them down one side & then slipped them on and ran a bead of caulk to seal the slice. Any new owners should get a giggle at the multi colored pipes under the house, lol
  • Michell Jarrett Michell Jarrett on Jan 09, 2014
    Annette, my house too, is from 1948 or before and I have to keep my water dripping when it gets as cold as it has been this week. All faucets were dripping from about the time it hit 35 degrees until it got above that so for about 2 and a half days. I only did the hot water faucets since the cold will not freeze if only one of the taps per sink are on. To help your indoor temps I would replace the windows with some that look just like the original but are insulated. I like to keep things original as possible but the electric bill pays for the expense after awhile. Your house is so cute. I love the way old houses are really bigger than they appear. The side of your house that doesn't have skirting underneath will make a difference with the pipes freezing, too. Hope you fare well with this. =)
    • See 1 previous
    • Annette C Annette C on Jan 10, 2014
  • Val Val on Jan 10, 2014
    Hi Annette, So glad everything worked out in the end! Val
  • Cathy Cathy on Jan 11, 2014
    our hot water did the same had cold and hot except in the north side of the house bathroom so we poured hot water down the drains and it finally came back on
  • Annette C Annette C on Jan 12, 2014
    It's happened before we just had more warning, I would try leaving the cubbard door open but we don;t have an inclosed subfloor, it's pier-beam & open on 3 sides, I thought about skirting the house but was told that would cause problems with moisture because of the humidity where I live now.
  • Annette C Annette C on Jan 12, 2014
    The end to my debacle was this, the connective pipe (hot water) between the master tub & sink had split, about 24 inches strait through the joint that connects to the sink. Wow water is a powerful thing or is it Ice? There must have been a pinhole because there was the neatest pyramid of ice in the middle of the lake of water emerging from under the house. Fix; 1 survivors weir wood saw. 1 48 inch length of PVCP 1 elbow & 1 couple 1 pot of glue & prep My son was enlisted to go under the house & he thought of using the weir saw when the traditional cutting pipe wrench was awkward to use in the small confines of the crawl space. Took no time at all, actually was faster than his cuts to the new pipe with the proper tool. The whole project from start to finish was about 30 min. Not including the dry time. I have decided that the reason I only had water in the cold taps was that the loss of pressure from the line brake in the hot water pipe was preventing the water to from flowing from the tank it's self. Sound right? So I had two days to melt the lines & one day to fix the problem & one night to let the pips set. Awwwg Four-ish days with no running water, I'm glad I wasn't in the hard hit arias that lost power for days, as we don't have a generator, lol And yes we did wrap the pips
  • Rachel Rivard Rachel Rivard on Jan 12, 2014
    Our hot water pipes to upstairs bathroom froze and split in two places because they are 1/2" copper, but the cold water pipe is 3/4" copper pipe. Both lines run inside bulkhead in garage (former owners did this-really dumb). Once repaired we put electric heating cables on both lines and plan to insulate garage doors. We are not use to -40C weather in Southern Ontario. Lesson learned the hard way!
  • Val Val on Jan 12, 2014
    Annette, that's hilarious about the pool noodles! Wish I'd thought of that! I'm glad you got the problem solved. Have a great day! Val
  • Grant Enterprises South Grant Enterprises South on Jan 14, 2014
    Hot water freezes faster than cold !!
  • Shirley Kalinosky Shirley Kalinosky on Sep 03, 2014
    I own a house in my hometown in NW Penna. Like you, this past January we were there and I hadn't put any heat in the laundry room. The hot water pipe froze and--long story short--the plumber came and replaced a small section of pipe. We turned off the water and put the pink anti-freeze (that is used in mobile home and travel trailers) in the toilet bowl after we drained the tank. We left it that way until mid-April when it finally warmed up. So this year, I may have to put the electric heater lines on the pipes and drain the toilet again, even though I will have the heater on. We have to keep the cabinets open and drip the water too. I don't need to have a flood again. Luck to you all that have to contend with the freezes.
  • Tammy Hixson Tammy Hixson on Jan 17, 2018

    B I U. I am putting hot water down the pipes to see if it works

  • Erin Erin on Mar 01, 2018

    Hi all,

    I am actually searching for answers and came across this post. We live in Ireland, but have our water system set-up like it would be in the US. It’s great when its working, but nobody here knows what to do when it’s not!

    It‘s unusually cold here at the moment (below freezing) and we can’t keep the house warm. The tank is in the attic, which is even colder.

    Our water is working out of all faucets, but the hot water is extremely cold. Is there a chance once the temperatures warm back up that everything will be ok, or is there definitely an issue?

    Any advice?!

    (Annette- your house is lovely!)

    Thank you in advance!

  • Rick Rick on Jun 15, 2018

    Having experienced this many times prompted a thought process that I believe definitively answers this "mystery" at least as pertaining to water pipes.


    - Hot water is less dense because dissolved air starts to release

    (listen to your shower before it warms, the tone lowers as warm water starts to flow - there's more free air in warm water, hence lowering tone.)

    - In as much as increased pressure in a diesel engine raises temperature to the point of combustion, (PV=nRT) in a closed system (closed pipe,) the reverse happens.

    - Fluids are essentially non-compressible but with more air in the hot water, as the temperature lowers, the air compresses and creates a vacuum that accelerates temperature decrease - essentially the reverse of the diesel effect.

    - This also explains why if you let the hot water drip slowly (relieving the vacuum,) it prevents the anomaly.