Tankless water heaters

[new land owner]

Making plans for my cabin and I was wondering who is using a tankless water heater and how good a job do they do supplying hot water.  Also I plan to drain the system in the winter between visits and I was wondering how easy it would be to drain one.

Thanks

[phalynx]

I have the Rinai and we absolutely love it.  More hot water than we can use.  We have it turned down and it will still provide hot showers for 2 showers at the same time in the middle of winter (not a harsh winter though)

[rwanders]

  I too, have a Rennai----great performance!  Critical factors to consider include temperature of incoming water and sizing your heater to match. My well water is about 38 and I have a 199,000 Btu propane fueled heater. Also, test your well for mineral content/hardness-----high hardness water can cause some problems over time if not treated.

[glenn kangiser]

We have the Bosch HX125 - since superseded by s new model.

It is great - generates it's own spark hence no standing pilot saving a lot of propane and money per year.  Keeps up with two things at once also -

Keeping the heat turned down from extremely hot reduces scaling on any of these type heaters and you still never run out of hot water.  I find it better to be a bit hotter than you can handle direct when washing dishes for better mixing of cold and hot.

A bit picky on temp adjustment but you will get used to it.  A money saver over tank type.

[MountainDon]

Are you thinking of a propane or nat gas type or electric?


Research how easy it is to drain. Best idea would be to inquire with the manufacturer/distributor and tell them what you want to do. I could be wrong or confused, but I seem to recall reading something somewhere about winterizing some brands being more difficult ot not recommended. It may be that the best way is to provide for blowing the heater out with compressed air. 


One thought... a tankless is a great way to save on the expense of heating and storing heated water as in a traditional water heater. However, if there could be any desire on your part to make use of solar heating for hot water, a tankless heater may not be the best choice. Or, in some applications a solar water heater could be used ahead of the tankless heater, saving on fuel.

[JRR]

I think for a cabin they might work well ...especially if installed "outdoors" as shown in the posted image.  But I see a number of suggestions/advertisements that may show several tankless heaters at "point of use" locations in larger homes ... just under the kitchen sink, inside the bathrooms, beside the washer, etc, etc.  Do these things ever fail and become leakers?  If so, it seems we may be bringing the leaker from the basement or mechanical room ... and bringing it to a really leak-sensitive area.

It just so happens that my 10 year old gas water heater became a leaker (no, correction; it became a gusher!) about a week ago.  Cold showers ever since.  Earth basement was ankle-deep in water before we realized it.  But I sure am glad this didn't happen up in some living area!

Unless someone can convince me these things never leak ... I'm going to stick with the smallest tank heater that will do the job ... and use a circulating pump for the hot water loop.

[MountainDon]

... and use a circulating pump for the hot water loop.

That's what we use in the house. Plus we have a galvanized tray under the tank with a sump pump that's all set up to cover us for any tank leaks that may happen. WH is inside the home in a utility closet.

[JRR]

Don, no surprise ... you got all the bases covered!

[new land owner]

I read this and I am still not sure which way to go.

http://www.consumerreports.org/cro/appliances/heating-cooling-and-air/water-heaters/tankless-water-heaters/overview/tankless-water-heaters-ov.htm

[MountainDon]

Using a tankless heater might require learning some new habits. The article mentions the issue of low flow like for shaving with the heater unable to deliver warm water at a low flow. That was a concern of mine, too. Our situation was a little different though. We were talking replacing an existing heater. We ran into impractical costs for the change from old storage tank system to a new tankless type. Then we were also confronted with a long run from the tank to our bedroom bath. One of the penalties of a one floor rambling floorplan.


If I was building a new home today where we are, I'd look at one of the tank type water heaters Dave Sparks mentioned. (brand name American I believe). They have a built in coil for use with a solar water heater system.

They also have an interesting gas fired "hybrid" water heater. I have not read up on it a lot but it is a small tank with an efficient burner. The claim is to be able to be used with a small gas line (that could have helped our choice) and to be able to deliver up to 189 gallons of hot water for the first hour.

http://www.americanwaterheater.com/products/default.aspx

the hybrid model ....  http://www.americanwaterheater.com/products/pdf/NRYSS00110.pdf

I hope that helps rather than confuses.

[Shawn B]

I'm not convinced that the tankless heaters are worth their price, the claimed efficiency, and the potential maintenance problems, like hard water, and parts availability.  I can buy a standard 40 gallon gas water heater for around $250-$300. The standing pilot light cost around $6-$8 month. Also the burner does not cycle that often if the tank is kept inside the main house, or is fairly well insulated.  If having a standing pilot light bothers some you can buy a model with a I.P.I ---Intermittent Pilot Ignition, and can vent the unit with P.V.C pipe, the only downside is it requires 120VAC. Not the big of deal if you are on grid or if you have a decent solar or wind system as most units draw less than 3 amps. Draining the tank is easy, simply open the valve and drain out a standard garden hose.

I think the biggest benefits of the tankless systems are their small size, ability to wall mount, direct vent.

[JRR]

I ended up installing the least efficient model of 40 gal gas fired that Sears sold ...because they had it in stock ... little woman wanted no more cold showers!  About $415 including state taxes.  I'm sure I could have found cheaper ones.  The new Sears models direct the incoming cold water against the tank bottom at an angle ... supposed to minimize the build up of sediments.  We'll see.

The old unit had lastest several years.  And the house water piping was a mixture of copper, brass, and galvanized threaded joints.  I decided to eliminate the galvanized. A new 3/4" pipe tap was used to clean up the copper threads that had been damaged by the neighboring galvanized.  I also decided to give Permatex "Thread Sealant with PTFE" (80631 -- 14A) a try.  Toothpaste consistency ... easier to apply than teflon tape.  High expectations.  BIG MISTAKE!!  Every joint leaked!  Gas ... cold water ... hot water.  Took every joint apart and went back to teflon tape .... no leaks!!

The first time I have ever been disappointed in a Permatex product!

[DirtyLittleSecret]

I ended up installing the least efficient model of 40 gal gas fired that Sears sold ...because they had it in stock ... little woman wanted no more cold showers!  About $415 including state taxes.  I'm sure I could have found cheaper ones.  The new Sears models direct the incoming cold water against the tank bottom at an angle ... supposed to minimize the build up of sediments.  We'll see.

The old unit had lastest several years.  And the house water piping was a mixture of copper, brass, and galvanized threaded joints.  I decided to eliminate the galvanized. A new 3/4" pipe tap was used to clean up the copper threads that had been damaged by the neighboring galvanized.  I also decided to give Permatex "Thread Sealant with PTFE" (80631 -- 14A) a try.  Toothpaste consistency ... easier to apply than teflon tape.  High expectations.  BIG MISTAKE!!  Every joint leaked!  Gas ... cold water ... hot water.  Took every joint apart and went back to teflon tape .... no leaks!!

The first time I have ever been disappointed in a Permatex product!

Tried that Permatex sealant as well.  Absolute JUNK.  Woulda been better to use JB Weld.

[MountainDon]

 I have had the opposite experiences. I've never used the permatex but I have used Rectorseal products for years and can not remember ever having a joint made using their product leak. That goes for gas, air and water. Every so often I use Teflon tape. Every so often one of them leaks. Not all, just once in a while.

[ScottA]

I use both teflon tape and teflon rectorseal. Put the tape on first with about 3 wraps then a thin layer of dope. Almost never get a leak.

[JRR]

I'll have to give that Rectoseal a try.  I like the concept of a paste ... as teflon tape can be difficult if you are working in limited space.

Have you guys ever tried pre-loading a few feet of tape onto the barrel of a cheap ball-point pen ... then using the pen barrel as a wand to work the tape around a fitting in limited space?

[newzorro]

Also, besides saving you up to 25% on energy costs, ENERGY STAR gas tankless water heaters are one of the qualifying energy-efficiency improvements that are eligible for a tax credit (in the U.S.) IF you make the change January 1, 2009 through December 31, 2010. If you're a U.S. resident, you should read over the tax credit info for 2009-2010 before you choose products.
There (thetanklessheaters.com) is also a calculator that allows you to calculate various parameters of the water heater.

[MountainDon]

 

[John_M]

I'll have to give that Rectoseal a try.

...that might be an interesting discussion if someone overheard only that part of your conversation....