# keeping water pipes from freezing **URL:** \ **Category:** Factual Questions\ **Created:** [November 28, 2009, 1:59am UTC](https://boards.straightdope.com/t/keeping-water-pipes-from-freezing/519188 "2009-11-28T01:59:20Z")\ **Posts on this page:** 9\ **Page:** 3
**Author:** ![raindog](https://avatars.discourse-cdn.com/v4/letter/r/2bfe46/32.png) [@raindog](https://boards.straightdope.com/u/raindog)\ **Post date:** [November 29, 2009, 4:17am UTC](https://boards.straightdope.com/t/keeping-water-pipes-from-freezing/519188/41 "2009-11-29T04:17:19Z")
> [@Magiver](#): > > I’ve seen frozen pipes with the thermostat at 70 (you should be familiar with Huber Heights slab construction from the 60’s). That was from cold soaked outdoor faucets freezing into interior pipes hidden in cabinets and walls. My parents lucked out when the pipe burst and the water shot back outside instead of flooding the house. I agree that a properly plumbed house will not have this problem but my experience with post construction “professional” plumbing modifications has been less than inspired. Homeowners will opt for the path of least resistance when it comes to having stuff ripped out. > > I don’t know what the winters are like in Chicago but if I had a house with a basement I would drain the system, shut off the water and lower the heat to 45 degrees. It’s a 10 minute job with a basement sink. Done. The pipes are 100% safe. It may be overkill but when you look at the time involved it’s an easy decision. Murphy can’t come back with a loss of electricity or gas due to utility work in the neighborhood (both have happened to me in the last 2 years). I agree. I suppose he may want water for cleaning, toilet etc. In that event, I’d simply shut the water off each day when leaving and set the WH to “pilot.” Of course, draining makes sure of things. I’m from Chicago, born and raised, but in Dayton now. I’ve found that Dayton is 5-8 degrees warmer, on average, than Chicago. I watch the weather and have lots of family there, and for the most part we get similar weather, albeit a bit warmer in Dayton. ---
**Author:** ![raindog](https://avatars.discourse-cdn.com/v4/letter/r/2bfe46/32.png) [@raindog](https://boards.straightdope.com/u/raindog)\ **Post date:** [November 29, 2009, 4:23am UTC](https://boards.straightdope.com/t/keeping-water-pipes-from-freezing/519188/42 "2009-11-29T04:23:22Z")
> [@old\_joe](#): > > Sorry you are confusing reality with something you read. When i lived up north (near the NWT border not montana) we would get 6 to 8 weeks of -45 to -50f every winter. Yes thats right, -45f. I can assure you that seeing frost on the **inside** living room wall means that its pretty damm cold. this would be a exterior wall that is directly exposed to the outside. So I agree with the poster that said its all about temps outside. > And yes cars really didnt like that weather! I’m the one that said that it’s all about temps outside. :smack: I’m not sure what your point is. In every part of the country furnaces are sized for the weather in that region. A 3000sf house in Atlanta will get a different furnace than a 3000sf house in Montana. If the weather there is such that there is 6-8 weeks of -45° weather, than I can assure you that construction methods and fornaces are installed for that reality. In any event, I think you actually make my point. ---
**Author:** ![raindog](https://avatars.discourse-cdn.com/v4/letter/r/2bfe46/32.png) [@raindog](https://boards.straightdope.com/u/raindog)\ **Post date:** [November 29, 2009, 4:25am UTC](https://boards.straightdope.com/t/keeping-water-pipes-from-freezing/519188/43 "2009-11-29T04:25:57Z")
> [@old\_joe](#): > > Sorry you are confusing reality with something you read. When i lived up north (near the NWT border not montana) we would get 6 to 8 weeks of -45 to -50f every winter. Yes thats right, -45f. I can assure you that seeing frost on the **inside** living room wall means that its pretty damm cold. this would be a exterior wall that is directly exposed to the outside. So I agree with the poster that said its all about temps outside. > And yes cars really didnt like that weather! If I understand you correctly… if there is frost on the inside exterior walls I can guarantee that it is not 15 degrees warmer 15 feet away at the stat location. I guarantee it. ---
**Author:** ![old\_joe](https://avatars.discourse-cdn.com/v4/letter/o/58956e/32.png) [@old\_joe](https://boards.straightdope.com/u/old_joe)\ **Post date:** [November 29, 2009, 5:57pm UTC](https://boards.straightdope.com/t/keeping-water-pipes-from-freezing/519188/44 "2009-11-29T17:57:18Z")
> [@raindog](#): > > I’m the one that said that it’s all about temps outside. :smack: > > I’m not sure what your point is. In every part of the country furnaces are sized for the weather in that region. A 3000sf house in Atlanta will get a different furnace than a 3000sf house in Montana. If the weather there is such that there is 6-8 weeks of -45° weather, than I can assure you that construction methods and fornaces are installed for that reality. > > In any event, I think you actually make my point. My comment was to the post that said that one wall cannot be whole lot colder than the rest of the house. Something about temps equalizing. Frost on the wall would prove that wrong. Its not the furnace at all. All the furnaces were more than adequate for the job. It the construction method, wood studs with insulation between them. The studs act “wick” the cold into the interior of the house. This happens only in extremes of climate. What should happen is foam insulation on the exterior of the whole house, providing a thermal break isolating the walls. But the building code does not require this. If you have never experienced long periods of very cold weather I can understand that it might seem unlikely but as the other poster said I have seen pipes freeze in a house where the thermostat was set to 72 and in fact was very comfy inside. You dont have to assure me that about construction methods and furnaces, I live it every day. Even though i live in the south of canada now its gets -25 (f or c) or lower with 60 to 80 km winds being commonplace in the winter. Again, temps inside the houses were normal shirt sleeve temps and yet you could feel exterior walls being very much colder than air temps. Homes were all built in the last ten years and biult to code.. ---
**Author:** ![old\_joe](https://avatars.discourse-cdn.com/v4/letter/o/58956e/32.png) [@old\_joe](https://boards.straightdope.com/u/old_joe)\ **Post date:** [November 29, 2009, 6:15pm UTC](https://boards.straightdope.com/t/keeping-water-pipes-from-freezing/519188/45 "2009-11-29T18:15:28Z")
> [@raindog](#): > > If I understand you correctly… if there is frost on the inside exterior walls I can guarantee that it is not 15 degrees warmer 15 feet away at the stat location. > > I guarantee it. You seem to like the word guarantee. I dont see whats hard to understand, when i am down in Yuma and I put my hand on the exterior wall its warmer than the wall where the thermostat is located. Try this thought experiment. Imagine a iron bar that goes through the wall, heat or cool the outside end. What happens to the inside end? Same things happens to wood studs in a house. Insulation is “between” the studs, not over them. So If the thermastat is set to 72f and i see frost on the wall I think it would be safe to say that the wall is colder than the air temp. It just occured to me that you are thinking that that whole wall is covered in frost. Not so, only spots. Again, houses with them thermastats set for normal temps had frost on the walls. Nice and warm homes, shirt sleeves temps, comfy… Direct observation. ---
**Author:** ![raindog](https://avatars.discourse-cdn.com/v4/letter/r/2bfe46/32.png) [@raindog](https://boards.straightdope.com/u/raindog)\ **Post date:** [November 29, 2009, 9:46pm UTC](https://boards.straightdope.com/t/keeping-water-pipes-from-freezing/519188/46 "2009-11-29T21:46:08Z")
> [@old\_joe](#): > > My comment was to the post that said that one wall cannot be whole lot colder than the rest of the house. Something about temps equalizing. Frost on the wall would prove that wrong. Its not the furnace at all. All the furnaces were more than adequate for the job. It the construction method, wood studs with insulation between them. The studs act “wick” the cold into the interior of the house. This happens only in extremes of climate. What should happen is foam insulation on the exterior of the whole house, providing a thermal break isolating the walls. But the building code does not require this. If you have never experienced long periods of very cold weather I can understand that it might seem unlikely but as the other poster said I have seen pipes freeze in a house where the thermostat was set to 72 and in fact was very comfy inside. You dont have to assure me that about construction methods and furnaces, I live it every day. Even though i live in the south of canada now its gets -25 (f or c) or lower with 60 to 80 km winds being commonplace in the winter. > Again, temps inside the houses were normal shirt sleeve temps and yet you could feel exterior walls being very much colder than air temps. Homes were all built in the last ten years and biult to code.. I don’t think you’ve read my posts. I’d be interested in your background because I don’t think you fully understand how these things work. The discussion you jumped into dealt with frozen pipes and a person’s question about whether they can expect their pipes to freeze at various setpoints on their thermostats. While most of what you wrote is irrelevant to that discussion, the parts that are support my point—your observations. **Philster** made the point that setpoints like 48° keep plumbers and insurance adjusters busy. Yet you give me an example of frozen walls and shirt sleeve temperatures in the house! That makes my point: If you do not have water pipes on the exterior walls (and most houses don’t!) it will not make much difference how cold it is outside. (assuming you have an appropriately sized and well running furnace) If you maintain 45° in the house the [interior] pipes will not freeze. On the other hand, you make my point when you observe that even when the temperature is “shirt sleeve” interior wall cavities will freeze. So the “problem” is not that the homeowner set the stat too low, but rather some fool put water pipes on exterior walls and than failed to a) heat trace, b) pipe insulate, and c) correctly wall insulate. As to the air temperature and wall; the wall may be cold during extreme cold, and cold to the touch, but within inches of the wall the temperature would be that of the ambient conditions. In any event, the frozen pipes are due to poor construction methods and not a 48° stat setpoint. Your observations are a good example. Building codes do not ensure quality construction. They are designed for safety primarily, and secondarily for things like energy consumption. Code would require insulation in your walls, but not that all the necessary caulking was done, or that the insulation was stapled at the appropriate intervals, or that it was shot with an infrared camera for thermal breaks before drywall was put up. So when you experienced frost “in spots” you were observing shoddy construction. I have no doubt that that wall could have passed an inspection, and “met code.” There is nothing inherent to Canada that necessitates frost on interior walls. But that’s all irrelevant: 6 inches from that wall the conditions were “shirt sleeve” ----72°----right? ---
**Author:** ![raindog](https://avatars.discourse-cdn.com/v4/letter/r/2bfe46/32.png) [@raindog](https://boards.straightdope.com/u/raindog)\ **Post date:** [November 29, 2009, 9:57pm UTC](https://boards.straightdope.com/t/keeping-water-pipes-from-freezing/519188/47 "2009-11-29T21:57:57Z")
> [@old\_joe](#): > > You seem to like the word guarantee. I dont see whats hard to understand, when i am down in Yuma and I put my hand on the exterior wall its warmer than the wall where the thermostat is located. Try this thought experiment. Imagine a iron bar that goes through the wall, heat or cool the outside end. What happens to the inside end? Same things happens to wood studs in a house. Insulation is “between” the studs, not over them. > > So > If the thermastat is set to 72f and i see frost on the wall I think it would be safe to say that the wall is colder than the air temp. It just occured to me that you are thinking that that whole wall is covered in frost. Not so, only spots. > Again, houses with them thermastats set for normal temps had frost on the walls. Nice and warm homes, shirt sleeves temps, comfy… > Direct observation. One last thought and I’m done wasting bandwidth. Your furnace----controlled by the thermostat------is designed to control the ambient conditions, _ **not** _ the wall temperature, or the temperature inside wall cavities. Still, it is possible to have frost on an interior wall and have air temperatures that are 70° six inches away; just as it is possible to have frozen Freon pipes in the backyard when its 95° outside. While the thermostat may be influenced by Btu loss in inefficient or poorly constructed walls and windows, (and drive the furnace as a result) it is quite possible to feel cold at the wall or inefficient windows. Your furnace will have little effect on the walls or windows, or the pipes in those walls if they’re poorly constructed. If the pipes freeze it’s not because the stat was at 50° (as more than one poster noted they freeze at 70°) it’s because you built a crappy wall. ---
**Author:** ![old\_joe](https://avatars.discourse-cdn.com/v4/letter/o/58956e/32.png) [@old\_joe](https://boards.straightdope.com/u/old_joe)\ **Post date:** [November 29, 2009, 11:45pm UTC](https://boards.straightdope.com/t/keeping-water-pipes-from-freezing/519188/48 "2009-11-29T23:45:46Z")
> [@raindog](#): > > One last thought and I’m done wasting bandwidth. > > Your furnace----controlled by the thermostat------is designed to control the ambient conditions, _ **not** _ the wall temperature, or the temperature inside wall cavities. Still, it is possible to have frost on an interior wall and have air temperatures that are 70° six inches away; just as it is possible to have frozen Freon pipes in the backyard when its 95° outside. Yep I agree with you. Thats why I disagreed with this > [@raindog](#): > > If I understand you correctly… if there is frost on the inside exterior walls I can guarantee that it is not 15 degrees warmer 15 feet away at the stat location. > > I guarantee it. seems like we both agree that you CAN have a 15 degree variation between stat and wall locations. BTW I pretty much agree with eveything else you said. ---
**Author:** ![raindog](https://avatars.discourse-cdn.com/v4/letter/r/2bfe46/32.png) [@raindog](https://boards.straightdope.com/u/raindog)\ **Post date:** [November 30, 2009, 4:06am UTC](https://boards.straightdope.com/t/keeping-water-pipes-from-freezing/519188/49 "2009-11-30T04:06:04Z")
> [@old\_joe](#): > > Yep I agree with you. Thats why I disagreed with this > > seems like we both agree that you CAN have a 15 degree variation between stat and wall locations. > > BTW I pretty much agree with eveything else you said. No…we don’t agree and I’m still puzzled what your point is. **Philster** said “…45 degrees near the thermostat means something MUCH less near an exterior wall…How nice. It is a cozy 48 near the thermostat…” It’s not just that that is not accurate, it’s the conclusion he (and apparently, you) draw from this: That it’s the result of a 48° thermostat setting. That’s not true. \*\*\*If the wall surface \*\*\* is cooler **it’s because of the wall construction not because of the stat setting.** **On the wall surface itself** it may be substantially cooler—and maybe even 15° cooler. But he said “near” the wall. There will be some gradient in the few inches----and it is inches----off the wall but the area “near” the wall will be close to the ambient. If the stat is set to 48° the area near the wall be 48°. If the wall is of poor construction-----or if there is a huge differential between inside and outside ambient like the extreme example you gave-----the wall surface will be cooler, but the ambient condition will be quite close to the stat reading. This will be the case if the stat is set to 48° or 70°; the wall will feel cooler. Even if you and I and Philster agree to only consider the wall surface itself (as opposed to the area near the wall) the conclusions you draw aren’t valid: that raising the stat will make that go away. It won’t. But the OP wasn’t concerned about the differential as much as not freezing pipes. In that respect, raising the stat setting would help, but ultimately very little if he sees the type of temperatures you describe. But in the end these 2 things are still true: 1. You can have a cold wall in a room that is—to use your term “very comfy inside”------ near the exterior walls. That’s not because of the stat setting, WHICH WAS Philster’s POINT. 2. You will have very little effect in preventing freezing by raising the stat setting to 60° if the real issue is poor wall construction. [Previous page](https://boards.straightdope.com/t/keeping-water-pipes-from-freezing/519188.md?page=2)