# Tankless water heater?



## tmillerrn (Feb 7, 2014)

Hello all. Finally my dreams are becoming real as I finally got my 504 sq foot cottage on my property. Now to start fixing it up! I am considering a tankless water heater. My cottage will have one utility sink (kitchen), and in the bathroom a sink, almost full size tub (I am fashioning a galvanized steel horse trough into a tub), and a shower. All in close proximity to each other and where I want to install this device. Should I get a whole house device, or a point of service unit for the kitchen and one for the bathroom (I have seen POS units that can handle a shower and a sink).

Anyone have experience with these? I live in central OK, so winters aren't horribly bad. Well water. I like my baths and showers hot, too!


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## mreynolds (Jan 1, 2015)

The POS units (some anyway) will take care of a shower unless you like it real hot. Have one in my work trailer. But to get one that works good you will need two circuits for it. The one 220 unit will not do it. So if you need two that's four circuits. 

If you get a single unit it will work better imo. The only drawback is when it goes so does all the hot water until you can get it replaced. But if it were mine that's what I would do.


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## farmrbrown (Jun 25, 2012)

That small a house, one will be fine.
An option you may want to consider is one that is NG or propane, no worries en=ven if the power goes out.:thumb:


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## Bottleneck (Apr 22, 2014)

Are you sure that the propane ones aren't pilot-less? If they don't have a pilot, they would use and electronic igniter. I want to say that I have heard the gas heaters are more reliable.


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## farminghandyman (Mar 4, 2005)

a small 10 to 20 gallon tank heater would do one or two persons fine, no one may not be able to take a 45 min shower but it should more than adquadatly provide all the how water that one needs, under normal cirmstances, and with just a little planning should not be a problem any time,


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## NorthwoodsMike (Jun 10, 2013)

Some gas models have an ignition that is powered by water flow. Others have blowers that need power. Are you on a well? Hard water can create problems as it can cause buildup. 

At our cottage, where we used to live full time, our family had a 15 gallon electric heater. We did swap in a bigger element for quicker recovery, but it worked great, and was very simple. If the element ever goes, $15 later will have us back in business.


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## doc- (Jun 26, 2015)

Lower over all energy cost of tankless water heater may not be offset by higher initial capital expense & don't forget repair/replacement costs when hard water ruins it.

Disadvantage is long warm-up time making it inconvenient & more expensive when a small amount of hot water is needed quickly, as in shaving or just washing hands.

Not what it's cracked up to be. Think twice.


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## bigrandy (Jul 21, 2003)

I used a 175 dollar electric tankless water heater in my old farmhouse for years we didnt have the best water pressure which I think helped


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## cindilu (Jan 27, 2008)

Following this thread because I have the same questions and doing the same project. Even down to the galvanized horse water trough for the tub. So good questions and looking forward to reading your answers as well.


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## cowbelle (Mar 5, 2009)

I have a propane one, by Aquastar, and have loved it for about 5 years. Mine has a pilot, which has blown out a few times - I'm sure it has to do with poor installation. My daughter has a pilot-less one, also propane, and also loves it.

Mine is in between the kitchen and bath - approximately 10' to each faucet. The delay in getting hot water isn't great - if needed, I just catch it for watering plants. Water is plenty hot!, and it is adjustable.


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## Bottleneck (Apr 22, 2014)

When I worked on a harvest crew, the trailer we lived in (a converted 52'reefer) had a propane tankless. It did a great job of heating the water, but if somebody else even touched a faucet or something. The temperature settings were absolutely wild. This was about 8 years ago though. Do the new ones do that too?


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## potter28 (Sep 10, 2014)

Not worth the money, even the new lp gas on demand water heaters will only give you about 4 gpm. So what that mean is u can take a long hot shower if the showerhead is flow restricted, if someone runs the dishwasher or does a hot load of laundry at the same time u will have a continuous warm shower. They are expensive to buy, service and replace. A simple 30 or 40 gallon electric water heater would work the best. Even from a cold start of the heater you should have hot water in 20-30 minutes, parts are few and cheap. Never needs replacing unless it leaks from the tank.


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## coyote556 (Jun 7, 2014)

I had the Bosch in my last house. It worked real well. You need a 200a panel. I had to run three separate 40a circuits to run it. We were real happy with the unit. It took a little tweaking to get the temps right upon initial install, but it was good.

One other thing you should know, do not install one unless you have a water softener. Hard water will destroy on demand unit.


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## beenaround (Mar 2, 2015)

I'd only use a tankless if a tank wasn't possible. I use a tank and a tankless of sorts, same deal as a tankless but is inside my wood fired boiler/heat. It's supposedly big enough to go on it's own, but I have it feeding the tank and the tank the house. Can't do that with a tankless heater. Round here the boiler is up to temp about 7 months a year. Means I'm not using any energy (you know what I mean) for domestic Hot Water that long.


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## Otter (Jan 15, 2008)

I have a mini-tank and LOVE it. Cheap to buy, easy to work with and service. You can't take a half hour shower, but you can have a nice hot one for 10 minutes, and the water will be ready for the next person by the time you're done brushing your hair and teeth.


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## Lisa in WA (Oct 11, 2004)

We've had a propane tankless aqua star for 14 years and love it. It's the one that is ignited by water flow.


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## tmillerrn (Feb 7, 2014)

So after even more researching, I have decided that my well water, which seems pretty hard, would be bad for these type of units. I even read it could void the warranty on some. My mom lives on my property and we have had to replace her heating element after only 8 months due to the hard water, in her regular water heater. I don't have gas out here. Just electric. I also a little scared of propane (stupid reason....). So I bought a 38 gallon, low boy electric water heater. Nice size tank, but takes up less space. For me and two kids, should be fine. Up until now, a 40 gallon tank at my parents cabin for 5 of us (running everything I mentioned as well as almost CONSTANT laundry, has worked well. Never run out of hot water....even after washing dishes, doing a few loads of laundry, and taking a long shower! I might consider propane in the future , but I have no experience with it at all and wonder how much it would cost versus electric water heater.


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## farmrbrown (Jun 25, 2012)

tmillerrn said:


> So after even more researching, I have decided that my well water, which seems pretty hard, would be bad for these type of units. I even read it could void the warranty on some. My mom lives on my property and we have had to replace her heating element after only 8 months due to the hard water, in her regular water heater. I don't have gas out here. Just electric. I also a little scared of propane (stupid reason....). So I bought a 38 gallon, low boy electric water heater. Nice size tank, but takes up less space. For me and two kids, should be fine. Up until now, a 40 gallon tank at my parents cabin for 5 of us (running everything I mentioned as well as almost CONSTANT laundry, has worked well. Never run out of hot water....even after washing dishes, doing a few loads of laundry, and taking a long shower! I might consider propane in the future , but I have no experience with it at all and wonder how much it would cost versus electric water heater.



That's good info on here.
I'm taking the opposite path with a similar situation at my Mom's place and I'll post back on this thread if she has any issues.
Right now, we're still waiting on the plumber to come out and install the tankless heater.........it's only been a month.:hammer:


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## chuckhole (Mar 2, 2006)

At my place in the country, I have a 30 gal LPG water heater with piezo-electric pilot and really like it. I also have a 3-gal under the counter electric water heater for a sink and like that too......for what it is. At my house in Houston, it is all electric since no gas is available. I hate cooking with electric but the 50 gal water heater is no trouble either.

The main thing is that you drain and service your water heater at least once a year to get the mineral deposits and sediments out and if it gas, wire brush the burners, etc. Gas or electric, they work better with maintenance. So, other than being partial to cooking with gas, lets take a look at the energy costs.

According to the US Department of Engery's Heating Fuel Comparison Calculator, the price per Million BTU's of heat (June 2014) is as follows:

#2 Fuel Oil @$4.02/gal: $28.99
Electricity @$0.12/KWh: $35.13
Natural Gas @$1.00/therm: $10.02
Propane @$2.93/gal: $32.11
Wood @$200/cord: $9.09
Pellets @$250/ton: $15.15
Corn @$200/ton: $14.29
Kerosene @$4.42/gal: $32.77
Coal @$200/ton: $8.00

I am a bit disappointed that LPG is not significantly less expensive than electricity like CNG is. But transporting electricity on your property is also expensive. Running heavy wire for larger circuits any significant distance can also be substantially more than the cost of gas SSFT (stainless steel flexible tubing) or copper. So much to consider. I like the idea that if there is a power failure, I can still heat, cook and have hot water. And my neighbor has a backup whole house generator that runs on LPG. Mine runs on gasoline.........it is what it is I guess.

We are in the process of building our barndominium..........and I am going tankless. And I am plumbing my connection points for the stove, HVAC, water heater and washer/dryer for both electric and gas. I want to be prepared for which way the wind blows in the future.


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## NorthwoodsMike (Jun 10, 2013)

Chuckhole don't be too disappointed. The LPG numbers for 2014 were messed up by a big shortage. At times it was $6.90 here. We switched to electric those months. 

Propane this past winter maxed out at 1.90 around here, making it over a third less than your diagram. Usually it's much less than even that!


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## tiffnzacsmom (Jan 26, 2006)

I have one in my trailer and it works well with three of us. We just installed one in my rental property yesterday. I ordered a Rheem off of Amazon for around $170


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## mousebandit (Feb 14, 2007)

I will be trying to fix an Aquastar propane tankless type soon. We're moving home, and it was listed on craigslist back home as working intermittently, and he only wanted $100 for it. So, I got a buddy to go pick it up for me, and as soon as I get home I'll be googling and youtube-ing all things aquastar and tankless heater repair and maintenance, LOL. 

My application would be in an off-grid cabin, so demand would probably be mostly dishes and bathing/shower needs. Right now, on our current property, the water supply is from a well, but I'll also be working on a rainwater cachement system and eventually water will hopefully either come from that, via gravity flow, or from spring water if we end up getting a different property.  

I'll keep ya'll posted, but in the meantime, anyone with experience with these suckers that have tips or suggestions (or warnings, LOL) they want to share, I'm all ears! 

Mouse Bandit


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## Ozarka (Apr 15, 2007)

The cost of 3 double-pole breakers and all that mess of 6-3G cable and the high purchase cost of the tankless heaters cancels out any supposed advantages they have over a tank. From the chart, gas is cheaper than electricity, even if it's propane. Wrap whatever kind of tank carefully with 6 inch fiberglass batts. Purchase a water heater timer from an electrical supply house, have it installed by a licensed electrician. Sorry, but whole house generators and solar electrical systems kinda rule out ANY electrical heating appliances. Especially the emergency heat strips in heat pumps. but that's a while 'nother thread...


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## Nevada (Sep 9, 2004)

farmrbrown said:


> That small a house, one will be fine.
> An option you may want to consider is one that is NG or propane, no worries en=ven if the power goes out.:thumb:


On the topic of electric or gas tankless water heaters, you can forget electricity. In the first place, they don't last long because the heating elements burn out quickly. Also, you need huge amperage to operate an electric tankless heater, requiring a 100 amp service for each 3 GPM. For an average house with a 6 GPM heater you'll need a 200 amp circuit, just to operate the heater. Often you'll need to install a new load center to accommodate an electric heater large enough for an average home.

Simply put, if you can do it with gas (natural gas and propane are both fine) then don't do it. You might consider a dedicated electric heater for a small sink, but if you're thinking of showering then you need gas.

To size a tankless heater you'll assume 3 GPM for each simultaneous shower, plus 3 GPM for a washer or dishwasher. Sinks are incidental, so don't count them. So if you wanted to be able to have two people showing at one time while running the clothes washer, you would need 9 GPM of heathing capacity (3 GPM for each bathroom, plus 3 for the washer). Multiple tankless heaters can be installed either in parallel or series if you need them. Parallel is common for just increasing hot water volume, and series is common when the objective is overcoming very cold incoming water temperatures in some climates during the winter.

You may also need to install a new gas service for a tankless heater. Conventional gas water heaters don't need a large service because they have all the time they need to recover from hot water usage. Tankless heaters require the heater to make hot water in real time, which requires a lot of gas during usage. A 3 GPM tankless water heater requires about 80,000 btu/hr, while a conventional gas water heater only requires about 25,000 btu/hr. If you have a 1/2" natural gas line to your water heater now that's longer than 20 feet you'll need to go to 3/4" pipe for a 3 GPM tankless heater, and to 1" pipe for a 6 GPM tankless heater. Check this table for pipe sizes.

http://www.engineeringtoolbox.com/natural-gas-pipe-sizing-d_826.html

Pipe sizes specifications for propane are smaller than for natural gas. Google for a chart on propane pipe sizes.

Now, for the types of heaters available. First is condensing vs non-condensing. Condensing tankless water heaters cool exhaust gases to the point where combustion water condenses. Condensing heaters are very efficient, but pricey. If you don't mind paying $1,000 for a water heater (without installation) then consider it, otherwise you're stuck with non-condensing.

Then there are modulated and non-modulated tankless heaters. That refers to the heater's ability to throttle water flow and flame intensity to maintain temperature. If you have 110v current available then you will want a modulated tankless heater, since water temperature is controlled much better. You can tell non-modulated units because they don't have a power cord and take two D cell batteries for ignition. Non-modulated heaters are OK in a barn or cabin where no power is available, but you'll want modulated for a home.

Finally, don't get screwed. Look at eBay for deals.

******
PS - When you go to install your tankless water heater you'll need an isolation valve kit. That provides necessary valves, hot-side pressure relief valve, and hose connections for flushing the heater from time to time. Those valve kits are available locally, but are pricey.

http://www.homedepot.com/p/Watts-3-...ater-Valve-Installation-Kit-0100156/205078015

You can find those for about half that at eBay, delivered.

http://www.ebay.com/itm/261402587079

Note that isolation valve kits are available for either threaded or sweat connections. Be sure to order what you want.

Obviously it pays to plan ahead for a tankless project. You should know when the life of your conventional heater is getting close to the end, and it won't hurt anything to have a tankless heater stored for a few years. Upgrading gas pipe can be done at any time. That could be the biggest part of the project. If that's already done when your conventional water heater does then the job will go a lot easier.


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## Nevada (Sep 9, 2004)

farmrbrown said:


> That small a house, one will be fine.
> An option you may want to consider is one that is NG or propane, no worries en=ven if the power goes out.:thumb:





potter28 said:


> Not worth the money, even the new lp gas on demand water heaters will only give you about 4 gpm. So what that mean is u can take a long hot shower if the showerhead is flow restricted, if someone runs the dishwasher or does a hot load of laundry at the same time u will have a continuous warm shower. They are expensive to buy, service and replace. A simple 30 or 40 gallon electric water heater would work the best. Even from a cold start of the heater you should have hot water in 20-30 minutes, parts are few and cheap. Never needs replacing unless it leaks from the tank.


Tankless heaters are competitive if you stay away from condensing models and buy smart. As I said before, you want a modulating tankless heater, which will throttle water flow and flame intensity to control temperature. Modulating heaters are the ones with a 110v power cord (not the ones that take 2 D-cell batteries). Here is an 8 liter/min (2 GPM) modulating model for about $90, delivered.

http://www.ebay.com/itm/331616962779

Mine is a similar 12 liters/min (3 GPM) model, but it's out of stock at eBay right now. The 2 GPM is ok but you'll probably need a pair of them for a small home. You can buy larger units, and even find them locally at Lowes or Home Depot, but they're very pricey.

Conventional (tank) gas water heaters run about $350. Admittedly, swapping a conventional water heater for a tankless can be a big project, particularly if you need to upgrade your gas pipe size. But if you can do it for anywhere close to the same price as a conventional heater you're ahead of the game, since tankless water heaters last up to twice as long as tank heaters (tankless last for 20 to 25 years).

For heating capacity, figure about 3 GPM for each simultaneous shower, plus another 3 GPM if you want to run the washer at the same time you shower. I have a 1-bath house and live alone, so 3 GPM is fine for me. You may need 6 GPM or even 9 GPM. Buy what you need or you'll find yourself short of hot water.

For the 2 GPM units linked above, you'll probably want 2 or 3 units piped in parallel for an average home in a mild climate like Oklahoma. You'll need a 1" natural gas service to the heater area (smaller for propane), and an isolation valve kit for each heater. These heaters come with flu pipes, so you save there. Mount them on an outside wall to make venting easy. The price for three 2 GPM heaters & three isolation valve kits will be competitive with a conventional heater and last twice as long. For a 1 bath home you'll get by with two heaters.


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## tmillerrn (Feb 7, 2014)

Lol! Info overload! Actually, all good info. I don't have the option of gas. I don't have a propane tank. Just good ole electric out here. But with my extremely hard well water, I did decide this wasn't quite the good idea I thought in the beginning.


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