# Why doesn't warm water come to a boil faster than cold water? **URL:** \ **Category:** Factual Questions\ **Created:** [July 25, 2010, 9:34pm UTC](https://boards.straightdope.com/t/why-doesnt-warm-water-come-to-a-boil-faster-than-cold-water/547979 "2010-07-25T21:34:07Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![Finagle](https://avatars.discourse-cdn.com/v4/letter/f/b19c9b/32.png) [@Finagle](https://boards.straightdope.com/u/Finagle)\ **Post date:** [July 26, 2010, 8:08pm UTC](https://boards.straightdope.com/t/why-doesnt-warm-water-come-to-a-boil-faster-than-cold-water/547979/21 "2010-07-26T20:08:25Z")
> [@Fridgemagnet](#): > > And think of that dead pigeon if you’re ever tempted to drink from the hot tap. Not sure where you’re located, but every single hot water tank I’ve ever seen (in the US) has been sealed and fed from the same cold water feed that you’d be filling your pot with. The worst thing you’d likely encounter in the hot water tank is mineral deposits. ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [July 26, 2010, 8:42pm UTC](https://boards.straightdope.com/t/why-doesnt-warm-water-come-to-a-boil-faster-than-cold-water/547979/22 "2010-07-26T20:42:21Z")
> [@Fridgemagnet](#): > > Thoughtfully, they will fill the kettle to the top for their one little cup so that many others after them will get to enjoy the taste of dead-pigeon-floating-in-a-loft-tank, with just a soupcon of Legionnaires Disease. The proper way to explain this is one cockpunch per syllable… Would someone translate this for me? Loft tank? Soupcon? Cockpunch? Even filling in guesses from the context, I don’t understand. Why would water from the hot tap taste worse than from the cold? ---
**Author:** ![Fridgemagnet](https://avatars.discourse-cdn.com/v4/letter/f/22d042/32.png) [@Fridgemagnet](https://boards.straightdope.com/u/Fridgemagnet)\ **Post date:** [July 26, 2010, 8:43pm UTC](https://boards.straightdope.com/t/why-doesnt-warm-water-come-to-a-boil-faster-than-cold-water/547979/23 "2010-07-26T20:43:21Z")
> [@Finagle](#): > > Not sure where you’re located… The UK, where we require the finest possible water for our tea. Except that we really stopped giving a toss a long time ago, and now people who can make a decent cup of tea are on the verge of extinction. We even have an Ig Nobel Award-for-Literature-winning British Standard (the equivalent of the US Underwriters Laboratory) on the subject - [BS6008](http://www.fatsquirrel.org/veghead/wot/BS6008.pdf). I print this out and pin it up in every kitchenette I pass through, in some vain hope that something will rub off. US hot water tanks may be a little different, but still thank-you no, if it’s all the same. Strictly speaking most of the hot water reservoirs in UK homes are of the immersion heater type, a big enclosed copper cylinder that usually resides in an airing cupboard in the largest bedroom. However, this immersion heater usually takes its water from a big tank in the attic, which definitely isn’t sealed, but there’s usually a bit of insulation over the top to keep it from freezing in winter and to strain out the chunkier lumps falling from above. This tank supplies the heating system and the bathroom cold taps (all non-potable), while the drinking water source in the kitchen is a direct feed from pressurised water mains. ---
**Author:** ![Fridgemagnet](https://avatars.discourse-cdn.com/v4/letter/f/22d042/32.png) [@Fridgemagnet](https://boards.straightdope.com/u/Fridgemagnet)\ **Post date:** [July 26, 2010, 8:53pm UTC](https://boards.straightdope.com/t/why-doesnt-warm-water-come-to-a-boil-faster-than-cold-water/547979/24 "2010-07-26T20:53:10Z")
For **CurtC** : Loft = attic; [soupcon](http://en.wiktionary.org/wiki/soup%C3%A7on); [cockpunch](http://www.urbandictionary.com/define.php?term=cockpunch). Try a taste test with water from the hot tap. If you like, do it double-blind and have someone prepare it for you with some cold tap, bottled and filtered water samples too (or whatever), and place the samples in the fridge for a uniform temperature. It should taste a bit flat, maybe with a hint of limescale and notes of copper. And possibly pigeon. ---
**Author:** ![Ms\_Boods](https://avatars.discourse-cdn.com/v4/letter/m/5e9695/32.png) [@Ms\_Boods](https://boards.straightdope.com/u/Ms_Boods)\ **Post date:** [July 26, 2010, 9:01pm UTC](https://boards.straightdope.com/t/why-doesnt-warm-water-come-to-a-boil-faster-than-cold-water/547979/25 "2010-07-26T21:01:05Z")
**CurtC** asked: “Would someone translate this for me? Loft tank? Soupcon? Cockpunch?” It pretty much sums up New Year’s Eve at **Mr F Magnet** ’s house\*. 🙂 \*I speak from first-hand experience. But he’s never fed me any pigeon soup because he’s a vegetarian. ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [July 26, 2010, 10:56pm UTC](https://boards.straightdope.com/t/why-doesnt-warm-water-come-to-a-boil-faster-than-cold-water/547979/26 "2010-07-26T22:56:04Z")
> [@Fridgemagnet](#): > > US hot water tanks may be a little different, but still thank-you no, if it’s all the same. Strictly speaking most of the hot water reservoirs in UK homes are of the immersion heater type, a big enclosed copper cylinder that usually resides in an airing cupboard in the largest bedroom. However, this immersion heater usually takes its water from a big tank in the attic, which definitely isn’t sealed, but there’s usually a bit of insulation over the top to keep it from freezing in winter and to strain out the chunkier lumps falling from above. This tank supplies the heating system and the bathroom cold taps (all non-potable), while the drinking water source in the kitchen is a direct feed from pressurised water mains. Really? Is this actually common? What supplies the tank in the attic? In the U.S. hot water heaters are almost universally sealed tanks fed by the same mains as the drinking water taps. The only real possible risk from the hot water tank is minerals. (And, I know this won’t make _you_ feel any different, but even if there was some biological contamination in a water supply, the absolute best way of dealing with it is, you know, um, boiling the water. A lot of people believe this is part of the reason for tea’s popularity with you Empire-building types) ---
**Author:** ![Penguinlady](https://avatars.discourse-cdn.com/v4/letter/p/f05b48/32.png) [@Penguinlady](https://boards.straightdope.com/u/Penguinlady)\ **Post date:** [July 27, 2010, 12:49am UTC](https://boards.straightdope.com/t/why-doesnt-warm-water-come-to-a-boil-faster-than-cold-water/547979/27 "2010-07-27T00:49:45Z")
> [@MeanOldLady](#): > > > [@Musicat](#): > > > > > [@Penguinlady](#): > > > > > > I was being facetious… > > > > When? When you said the experiment was highly scientific or when you said you didn’t use a thermometer? > > > > This Forum is **General Questions,** where a question is expected to have a factual answer (not that some tomfoolery isn’t expected to liven up the discussion). If you don’t have a serious question, maybe one of the lighter fora would be more appropriate? > > Jeez, relax. I’m sure the **Penguin** does want a factual answer to her question, but was being facetious when she said her experiement was “very carefully controlled [and] highly scientific.” THANK YOU! 🙂 ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [July 27, 2010, 2:36am UTC](https://boards.straightdope.com/t/why-doesnt-warm-water-come-to-a-boil-faster-than-cold-water/547979/28 "2010-07-27T02:36:29Z")
> [@Fridgemagnet](#): > > US hot water tanks may be a little different, but still thank-you no, if it’s all the same. Hot water tanks in the US are sealed and have the same input water as the cold lines. No dead birds, although you might get some accumulated rust in the hot water tank. [Previous page](https://boards.straightdope.com/t/why-doesnt-warm-water-come-to-a-boil-faster-than-cold-water/547979.md?page=1)