# Tankless Hot Water Heaters--your experience? **URL:** \ **Category:** Factual Questions\ **Created:** [March 8, 2015, 8:16pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549 "2015-03-08T20:16:52Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [March 8, 2015, 8:16pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/1 "2015-03-08T20:16:52Z")
How much space do they use? (I’d like to reclaim some closet space). Are they prone to breaking? Useful for home clothes washing machines? Electric, or gas? Cost? Any general info, at all? ---
**Author:** ![SHARKBITEATTACK](https://avatars.discourse-cdn.com/v4/letter/s/91b2a8/32.png) [@SHARKBITEATTACK](https://boards.straightdope.com/u/SHARKBITEATTACK)\ **Post date:** [March 8, 2015, 8:25pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/2 "2015-03-08T20:25:39Z")
About the same space as a circuit breaker box. They are more efficient because they only heat the water you need. Also you’ll always have hot water. Unlike if you are the second person to take a shower or right after using the washing machine. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [March 8, 2015, 8:31pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/3 "2015-03-08T20:31:26Z")
some previous discussion here > **[Tankless water heaters -- any experience or advice?](https://boards.straightdope.com/sdmb/showthread.php?t=750178)** > > My 50 gal electric water heater has failed after 60 years of faithful service. I’ve been intrigued by the idea of using a whole-house, tankless, on-demand, electric water heater. It would be nice to reclaim some space in the basement utility area... > **[tankless water heaters - what do you think?](https://boards.straightdope.com/sdmb/showthread.php?t=741818)** > > My water heater is 10 years old. The salesman came to the door with a month of that ten year date to get me to replace it. Do I need to replace it? A replacement would mean more payments. A tankless system was offered but the total cost would be... > **[Why are people still buying tank water heaters?](https://boards.straightdope.com/sdmb/showthread.php?t=710532)** > > I don’t get why there is even still a market for tank-based water heaters. On-demand heaters use less energy, take up almost no space, are less expensive and never run out. Why on earth would someone who needs a new water heater buy the tank kind? ... > **[Tell me about tankless water heaters (need answer fast)](https://boards.straightdope.com/sdmb/showthread.php?t=685360)** > > Existing tanked one appear to be leaking; therefore, I need to buy a new one. Are tankless ones worth it? I know they cost more upfront & have lower operating costs. How long (# of years) until break-even? I understand that they produce hot... > **[Tankless water heaters: opinions wanted](https://boards.straightdope.com/sdmb/showthread.php?t=581285)** > > We’re considering replacing our standard water heater with a tankless heater. Has anybody else done this, and if so, what has been your experience with repairs or problems? Please indicate how long you’ve had it. We are familiar with the small,... ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [March 8, 2015, 8:42pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/4 "2015-03-08T20:42:36Z")
1. A lot less space. 2. All appliances break. It’s just a matter of when. Quality tankless heaters have a good reputation for longevity as they are fairly simple devices. 3. Yes. 4. Gas. Electric tankless units require a truly serious amount of juice. 5. More. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [March 8, 2015, 9:23pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/5 "2015-03-08T21:23:48Z")
From one of the links above: > [@Tankless water heaters: opinions wanted](https://boards.straightdope.com/t/tankless-water-heaters-opinions-wanted/556613/2): > > I have a tankless in my house. > > First off if there is a leak from the pipes you will still get water everywhere. > > In my case I had to upgrade the gas piping from 1/2" to 3/4" this was due to the size of the unit I installed. This was a pain in the ass. > > I also had to relocate the water piping (not nearly so much work) This is because the tank style gets the water in from the top, the tankless gets it from the bottom. > > You will probably also have to upgrade the vent system. > > Overall I am very happy with the converstion, I would do it again. > > Do some serious reading on the installation requirements. Upgrading the gas pipe and the vent might be a deal killer in a basement application. > > If there are any other questions, feel free to ask. I’ve had the unit for many years now and I am still quite happy with it. I bought a BIG unit so capacity is not an issue. I did have a motherboard fail but it was covered by warranty. I did have to take the burner out once and clean it. If you have any questions, ask. ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [March 8, 2015, 9:40pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/6 "2015-03-08T21:40:06Z")
There’s no gas in my condo building, so that’s out. Sorry to bother you. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [March 8, 2015, 9:44pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/7 "2015-03-08T21:44:26Z")
You could always go with [point-of-use electric heaters](http://www.lowes.com/pd_481492-50857-AQM+2-1_0__?productId=4744353). Compact and efficient. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [March 8, 2015, 9:50pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/8 "2015-03-08T21:50:28Z")
Time to check in. After two weeks of no hot water – just a pot on the stove, always simmering – I now have replaced my 50 year old (not 60, my bad) electric water heater with a newer model. I found a plumber who didn’t fear tackling a retrofit, although he spent 4 hours working on it, and I contributed a _lot_ of backbreaking muscle getting the old tank up the stairs and the new one down. Probably not a good idea at my age, but so far, no lasting effects. The old tank was wired with a 20amp, 240v, #12 wire size circuit. Although the modern specs call for a 30 amp circuit, #10 wire, and a separate ground wire (not using the conduit for ground), the installer said the new tank had exactly the same element wattage as the old, so as long as it didn’t blow circuit breakers, it wouldn’t be unsafe. In 50+ years, I can’t recall the breaker ever tripping, and it hasn’t recently, either. The new tank is sized at 50 gals, exactly the same as the old (the plumber said 40 gals was an odd size, and he didn’t have one), but is incredibly only 2/3 the size (volume) of the old. The plumber said that was not due to more compact water molecules ( 😃 ) but better insulation, foam instead of fiberglass. However, the warranty is only 12 years, not 50! With any luck :rolleyes: , I won’t be around to see it replaced. The new tank isn’t as hi-tech as I had planned (no bright LED temp display or wifi interface), but so far, is working fine. I may boost the default temp a little, as I think the default is intended to be safely low, but the numbers on the tiny dial, hidden under a baffle, are too small to read without a microscope. I don’t yet have the final bill, but I think it will be reasonable, considering the outrageous estimates I received. I had the installer put in two valves so disconnecting the tank from the main line would be easier in the future, and I’m willing to pay for this upgrade. So I guess tankless heaters’ time has not yet come. Much like solar, wind power, and electric cars – much promise, less delivery. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [March 8, 2015, 9:58pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/9 "2015-03-08T21:58:47Z")
> [@Chefguy](#): > > You could always go with [point-of-use electric heaters](http://www.lowes.com/pd_481492-50857-AQM+2-1_0__?productId=4744353). Compact and efficient. That would cost me 3 X $150 for the hardware alone (3 sinks, shower, ignoring laundry), plus 200 for each electrical line (who has a spare AC outlet under their bathroom sink?), plus GFCI for all (more ). Total cost – beyond outrageous. Local plumbers tell me they only install these for people who want hot water for instant tea in the kitchen, not for the bathroom sinks. Maybe they’re just not up to date, but none of them will install one unless I beg, and I can’t do it myself. ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [March 8, 2015, 11:44pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/10 "2015-03-08T23:44:47Z")
> [@Chefguy](#): > > You could always go with [point-of-use electric heaters](http://www.lowes.com/pd_481492-50857-AQM+2-1_0__?productId=4744353). Compact and efficient. But not for clothes washers. What kind of costs are talking about, for electric tankless? ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [March 8, 2015, 11:52pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/11 "2015-03-08T23:52:54Z")
> [@Bosda\_Di\_Chi\_of\_Tricor](#): > > How much space do they use? (I’d like to reclaim some closet space). Most of my experience is with gas tankless heaters. A closet may not be the optimal place to install a gas tankless water heater because it needs a lot of air and matching exhaust. It will suck air at a high rate and will cause outside air to enter through window/door crevices and increase your HVAC costs. Check your gas meter to see if it has enough high capacity to supply the new heater - the heater takes a fair bit higher gas flow especially during startup. Make sure you have adequate gas piping to the closet. Depending on the hardness of the water, you probably will need to de-lime every year. Its good if you have space for that near the heater. > [@Bosda\_Di\_Chi\_of\_Tricor](#): > > Are they prone to breaking? Yes. This depends on the brand a lot. Doing DIY repairs/installation usually voids the warranty. You also have to mail order parts (usually not available in local hardware stores) - so you are out of hot water till the parts arrive. You also need trained personnel to do the installation / repair not the usual handyman. Useful for home clothes washing machines? No more or less than the traditional heaters. The tankless heaters have a low flow cutoff to protect overheating. Check this setting - if your washer takes low flow of water, the unit will not turn on. This is also true if you use water from any tap at a low flow rate. > [@Bosda\_Di\_Chi\_of\_Tricor](#): > > Electric, or gas? I do not have experience with Electric. Gas gives you better savings. > [@Bosda\_Di\_Chi\_of\_Tricor](#): > > Cost? Fairly high and IMHO the savings (and the hassles) do not justify the cost. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [March 9, 2015, 1:05am UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/12 "2015-03-09T01:05:12Z")
> [@Bosda\_Di\_Chi\_of\_Tricor](#): > > There’s no gas in my condo building, so that’s out. > Sorry to bother you. I have an electric tankless water heater in my gas-free condo. It supplies the kitchen sink and does a very nice job of near instant, very hot water in a limitless supply. The unit is about 8"W x 12"H x 3"D and takes a 220V split phase 30A power supply. It’s 10 years old and trouble-free so far. The dishwasher & clothes washer are also in the kitchen and are supplied with cold water only and have integral water heaters. I suspect either or both could have been plumbed off this unit too. The previous owner did the installation this way for whatever mysterious reasons. The bathrooms are fed by an electric conventional tanked water heater. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [March 10, 2015, 1:30am UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/13 "2015-03-10T01:30:26Z")
Last Friday, off I went to our local HVAC / plumbing supply house to purchase a gas fired tankless demand style H2O heater. Based on my online research, I felt confident this was the logical replacement option for my worn out electric tank. As it turned out, not only did they change my mind, they wouldn’t even sell me one if I had persisted… They stopped carrying them three months ago, and had dropped all service agreements related to them. Reason being the atrocious lack of reliability they experienced with the tankless units over the years. Number one on their list of problems was an unacceptable rate of (VERY!) premature failure in the heat exchanger. The three manufacturers they had represented were all top rated. These were not cheap-o, offbrand knockoffs. This is an old, well established supply house that also does installations. It is staffed by experienced old-timers and young, smart people. Their advice to steer clear of these things was good enough for me, despite the glowing reports I had read online. Disclaimer: YMMV ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [March 10, 2015, 1:42am UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/14 "2015-03-10T01:42:45Z")
> [@LSLGuy](#): > > The dishwasher & clothes washer are also in the kitchen and are supplied with cold water only and have integral water heaters. Your clothes washer has a built-in water heater? I’ve never heard of such a thing. Every washing machine I’ve seen has to be supplied with hot and cold water. ---
**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\ **Post date:** [March 10, 2015, 2:39am UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/15 "2015-03-10T02:39:20Z")
I believe my Bosch front loader washer has a heater to maintain temp. At least my wife says so and she’s read the manual. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [March 10, 2015, 2:44am UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/16 "2015-03-10T02:44:53Z")
I asked my plumber and he mentioned the issues with venting. He’s concerned the closet my current gas hot water tank is in doesn’t get enough air. Its pretty small closet. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [March 10, 2015, 2:33pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/17 "2015-03-10T14:33:09Z")
> [@Dewey\_Finn](#): > > Your clothes washer has a built-in water heater? I’ve never heard of such a thing. Every washing machine I’ve seen has to be supplied with hot and cold water. Yep. Asko model W660. It’s a Swedish machine designed for those eco-conscious Europeans. It does have the ability to be plumbed for hot water too, but it’s not necessary. It provides selectable wash water temps between 30C & 95C. All rinses are cold only. Although around here the “cold” water is usually in the mid 20C range. ---
**Author:** ![Doyle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/doyle/32/439_2.png) [@Doyle](https://boards.straightdope.com/u/Doyle)\ **Post date:** [March 10, 2015, 4:05pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/18 "2015-03-10T16:05:20Z")
Does anyone know if an electric tankless would still be cheaper than a traditional electric hot water heater? ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [March 10, 2015, 5:50pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/19 "2015-03-10T17:50:49Z")
> [@Doyle](#): > > Does anyone know if an electric tankless would still be cheaper than a traditional electric hot water heater? To operate? Almost certainly. Cost = temperature delta \* time. Keeping unused water hot in a tank all day costs money. Money you’re not spending with tankless. To buy originally, and to retrofit into an existing tanked installation? Probably not. The tankless device costs more to buy and if an electrical upgrade is needed those are pricy. Not to mention some small amount of plumbing rework to boot. Whether the greater upfront costs will be offset by the lower operating costs for \*you \*depends on \*your \*particulars. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [March 10, 2015, 6:12pm UTC](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549/20 "2015-03-10T18:12:39Z")
The vast majority of water heaters fitted in the UK are gas fired ‘combination boilers’. These are usually hung on an outside wall in the kitchen to keep the hot water run to the most frequently used tap as short as possible. They also provide the heat (and include the pump) for the wet central heating. These ‘boilers’ (a misnomer, since they do not boil). Hot water for washing, showering, bathing etc is heated on demand, so it is unlimited. The central heating (another misnomer) is controlled both by a thermostat and all but one radiators (again with the wrong name) are fitted with individual thermostats. These heaters are gas fired with electric ignition and the fan assisted flue works in both directions - drawing air in, and venting the combustion gasses. All the washing machines and dishwashers I have owned in the last 30 years have been cold water input only. The reason is probably that, the hot water supply has to wait for the heater to ignite and then for the cold water in the pipework to be used up before it flows hot. It is far more efficient to have a heater in the machine. The ‘boilers’ don’t boil; the ‘central’ heating isn’t central and the ‘radiators’ work mostly by convection. [Next page](https://boards.straightdope.com/t/tankless-hot-water-heaters-your-experience/714549.md?page=2)