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Question DetailsAsked on 6/10/2013

Are tankless water heaters worth it?

I''m thinking of replacing my traditional water heater with a tankless, on demand one. I have no idea if it would be cost beneficial or even a good idea. I am searching for information from someone who has had experience with these type heaters. I've heard that I might need to change out my electrical system, even though it was updated several years ago. Thank oul

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9 Answers

Voted Best Answer

I've seen and heard mixed reviews. They aren't really popular here due to our super hard water which clogs and rots everything it sits in. A company I used to work for tried electric units about 10 years ago in several homes but had to replace many of them within a few years because the build-up from the hard water hindered their productivity to little more than enough supply to run a sink. I've heard better success with gas units since there are no electric elements to burn out and gas can get hotter, faster to get through the deposits on the tubing walls inside the unit.

Standard electric water heater usually take a 30 amp circuit so they are often wired with 10 guage wire. Electric on-demand units large enough to service an entire house usually take 50 amps (or more) from what I've researched in the past. That means they need a 50 amp breaker and will be wired with 6 guage wire. By the time you factor in the initial cost of buying the much more expensive on-demand unit and rewiring for it I'm not sure you'll save money in the long run.

A better and cheaper option would be to put a timer on your standard water heater so it only kicks on during typical demand times. They have override switches so you can turn it to cycle normally when you are off of work or need it during the day/night if not during the preset times. A cheaper point of use water heater at the kitchen sink will ensure you have hot water there even when the main heater is off. This is usually the point that requires hot water the most frequently. Remember that your water heater will hold hot water for over an hour once it has cycled off. Take advantage of that.

Todd Shell

Todd's Home Services

San Antonio, TX

Answered 7 years ago by Todd's Home Services


Am not much of a fan of same, would rather see you invest in an outside air water heater. If you have a way to vent it. An outside air waterheater uses non interior air for the burner ie non conditioned air saving you 2 ways. 1)No waste of heated or cooled interior air & 2) You are not depressurizing the basement and pulling in possible radon gas. Plus if you have a high effieciency furnace you can close that huge airleak in your roof called a chimney. Check with local utility for more verification.

Jim Casper Old Energy Conservation Guru

Answered 7 years ago by jccasper


With your reference to electrical upgrade, I would assume you are considering an electric tankless. Yes an upgrade is often needed. The saving are that you only pay to heat the hot water you use, with a tank, you pay to keep it hot all day, even if you use none.

The first answer wa in regard to Gas type instead of electric.

There's definately saving with either type, I plan go tankless when it's time to replace, or before.


Answered 7 years ago by BayAreaAC


The primary complaint about tankless water heaters is that, unless you pay for a really oversized one, they do not keep up with high demands like clothes washer or tub or shower, or if you have multiple hot water demands going at one time.

The reason hot water heaters are used is because they can heat up and store enough water for an ordinary demand like a shower or clothes washing, and larger ones like 50-60 gallons can handle multiple simultaneous demands. Out 60 gallon heater handles washing machine, dish wahser, and a shower simultaneously without going from hot to warm. An on-demand system heats the water as it flows through the heater, with production of hot water having to equal the total demand at any instant. This they can rarely do - especially gas-fired ones, for which the power is usually much cheaper than with electricity.

Google the search phrase - on demand water heaters

to read articles on the issue, and EPA and EnergyStar program writeups. Consumer Reports also has comparisons and evaluations (though you have to subscribe to read review articles).

Answered 7 years ago by LCD


Yes - we have a gas-fired one for a full household for the past 7 years (3 kids and big dog in the household so we use lots of water a lot) with no problems with plentiful hot water. Very economical and environmentally responsible. Be sure to get one rated for at least 7 or 8 gallons/minute. Smaller ones are great for a separate cottage/suite with a single bathroom and kitchen. If your household likes baths, these are the best way to go. Highly recommend that your shower heads and appliances are high efficiency - hot water provision (at 120 degrees, much hotter than you need for a shower) maxes out at about 3 gal/min. Full size gas heaters need a 3/4" gas line with specific vent requirements - this can get expensive so be sure to get the pricing and install details up front. They generally have an electronic or water-demand-driven igniter so there is no standing pilot. Maintenance is minimal - just have to infrequently check the inlet filter screen and the thermistor (or whatever it's called) that is part of the thermostat. Much less work than annually flushing a tank heater or dealing with eventual tank rust, leaking, and pressure valve blowing. My only experience with an electric one is in a workshop that did not have gas supply and wasn't used much so a standing tank made no sense.

Source: Park City, UT

Answered 7 years ago by Guest_99509743


In most cases, I think the answer is "No, they are not worth it." Cost to buy the units are higher than tank heaters by far. Installation in new construction is not too bad but to retrofit into existing homes can be very expensive for labor and materials. One consumer publication has payback at 20 years, so this is not a project that save money except over the very, very long haul, and that assume gas and electricity pricing stay constant. Another issue is fuel. The savings tend to be far less than most expect because of the high fuel consumption of tankless models. For example, a 50-gal tank heater may have a burn rate of 35,000 BTU or so in efficient models. A tankless model requires at least 165,000 BTUs and are available up to 230,000 BTUs. Thats many, many times the gas needs of a tank model. Those rates may require a new larger gas meter, larger gas lines throughout the home, and venting the combustion. The tank model only burns these high amounts of gas while on but that could easily be for over an hour each day given length of showers, dishwasher and washer cycles, baths, etc.

Source: consumer publications, data plates on several water heaters

Answered 7 years ago by SalisburySam


Tankless, On Demand, Insta Hot, heaters are worth the savings in electricity over a storage type heater due to the absences of standby losses of keeping 40,50, or 60 gallons of water heated all the time. Water is heated instantly the second you open the hot water valve, and electricity is turned off the second you shut the valve. The cost of a new 50 gal storage heater is around $385 to $599, a Tankless 22kW heater will cover all the needs of a 3brm house and 2 showers at the same time, will cost $560 to $677 depending on who you buy it from.

Electrically your house has to have a 200Amp service panel. Your regular heater uses a 30amp 220V breaker, the tankless uses 2 -220V 50amp breakers so you need room in your service panel for another 220V breaker, because you'll be using the space from the old heater.

Larger wire from the breaker to the heater is required, so the closer you can put the Tankless to to the service panel is a bonus. All the info on sizing your heater for your house and location can be found at I have been Tankless for 8yrs and no problems, my neighbor followed 3yrs later , and then his neighbor last year, and all wish they had done it sooner. The Germans have had tankless water heaters for 60 years.

I hope this helps.

Answered 6 years ago by Guest_9189844


I know this is an old question but there are a few errors in the answers. To comply with the warranty of the device, tankless heaters do have to be flushed annually with a solution like white vinegar. just like your coffee pot. On natural gas, they would save a lot of power compared to an electric heater. On propane, they probably just eke out an advantage over electric. I would not use a propane standing water heater due to the cost of energy.

Overall, I think the tankless heaters cost more to operate than a standard electric heater but I don't know about the heat pump models.

On demand heaters do have a few other problems. the biggest is cold slices, you turn the hot water on then off then back on you might get a long shot of cold water since the heater has to run water to determine the heating parameters. This will prevent you from doing those on and off shower things but most people don't do that anyway. I think the biggest problem this causes is with dishwashers and washers. Even if you preheat the water by running it at the sink then turn the water off and start the dishwasher on, the cold slice will fill the dishwasher and it will have to reheat the water. In most cases that is not a problem and is probably more efficient than preheating except with some Bosch dishwashers which tend to burn the control board if the internal heater runs to long a cycle.

The second case is a washer that regulates inbound water temperature. The washer turns the hot water on and off and induces the cold slices. I don't know what, if any, impact this has on clothes cleaning.

I have an electric tank and a propane tankless and use them as needed. The tankless delivers hot water as long as you have gas and water and can fill big tubs effortlessly. If there aren't many people in the house, I often use it. But on the whole, we use the electric far more. It is located in a utility room on the lower level walkout basement which usually needs some heat so the lost heat from the unit is not wasted. If I had to choose one, I would take the electric tank if there were no big jetted or soaking tubs to fill (which require two tank heaters).

If I were going to spend a $1000+ on a water heater today, I would check out the heat pump models first. Start at Consumer Reports.

Answered 5 years ago by TroyV1


Relevant to this question is: Purchasers and owners of tankless water heaters may wish to consult with the latest Consumer Reports (February 2015) for details on the recall of 30,000 units so if they already have installed one they stop using it or if in the market for one, they do not unknowingly buy one onliine.

The recall applies to all single and dual purpose heaters made by COAIRE and also QUIETSIDE brands which are made by DAESUNG CELTIC ENERSYS of Korea. The units were from both Dealers and online purchases in the July 2008 to August 2014.

According to Consumer Reports, users should immediately stop using them and contact Challenger Supply Holdings at 1-800-729-6118 to obtain a free repair. [This information may also possibly inform someone who might otherwise buy one online from some liquidator, unknown source or other questionable party in either the new or used market.]

Source: Consumer Reports, February 2015, p. 21

Answered 5 years ago by SeaJay


I've had 5 propane tankless and 2 electric tankless. Both electric units failed within a year due to hard water and poor control designs. It also takes a lot of amps to heat several gpm.

2 of the propane units are in use as floor radiant heating furnaces. They work extremely well, 4 years and 9 years in service.

3 of the propane units are in domestic hot water use, all in service 9 years. They handle 2 showers ok with unlimited hot water.

All units are Takagi and with the very smart controls and variable burners they have there is no temperature cycling. All were installed with outside air supplies. The only reason for propane (other than the high btu content) is natural gas wasn't available.

There are several excellent brands - Bosch is one, where a friend has 4 in service at a remote camp.

Answered 5 years ago by fgs

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