[climber_grrl]

Someone asked a question about tankless water heaters in another thread, so even though I'm not a plumber or a distributor or anything more than a researching fool who recently decided on and purchased her own tankless, I thought I'd open up this thread for general questions.

There are some general concepts to understand about tankless water heaters.

First, yes, they are more expensive initially than a tank version. However, based on your heating method (gas or electric) you can make up the difference in the purchase price in a very short amount of time by the energy cost savings (we estimated 13 mo. and we use propane). A tankless is also expected to last 50% to 100% longer than a tank so it amortizes to less per year of service, as well.

Second, there are lots of products on the market and the unit needs to be sized to suit your size family, number of bathrooms, and daily water usage. I found all kinds of good data and stores online, but I kept going back to and ultimately purchased from DesignerPlumbing.com (Compare Tankless Water Heaters). They were very helpful via both phone and chat and had a good price compared to what I could find locally (I'm all for the no tax aspect of the web). We did have a plumber install it, but it was the 1st one he ever installed. We were just too busy and the plumber was already onsite for other jobs.

Third, tankless does not equate to on demand. On demand are those point-of-use units you install under a sink. Tankless is for use for your entire house. Just like with a tank, you need to wait for the hot water to flow through your pipes and come out your faucet. Since there is no hot water just waiting to flow when you turn on the tap, we noticed that it takes longer to get hot water than w/our old electric tank because a tankless requires water to flow at a certain rate (definitely more than a trickle) for a certain amount of time (3 sec I think) in order for the unit to register that hot water is being demanded. Only once the unit kicks on does it start heating water. So, we do have to wait longer, but once it's hot, it's hot for as long as you've got the water flowing at the proper rate.

That's probably enough to jump start the questions, so ask away and I'll do my best to either answer them or point you in a direction where you can find the answer yourself.

[kelly]

Thank you for bringing this topic up! I did some initial investigating on the tankless water heater and was a little concerned about the "not on demand" thing. My sister's remodelled home (which she bought post-remodel) has a traditional tank and a tankless. I'm not entirely sure how they function (eg does one serve the older parts of the house and the tankless the new, or, do they compliment each other across the grid?).

Eventually, we will be adding more bathrooms to this house, and I want a steamshower. 3 seconds doesn't seem too difficult a wait- I have heard longer wait times, however- like 5 mins?? Seems odd. Perhaps someone can comment on their experiences, and if anyone knows how a traditional and tankless work togehter, that would be lovely info.

Thanks!!

Kelly

[J.]

Thanks for starting the thread! My Townhome is all electric so I guess our savings would be different. You mentioned something in the other thread about putting the heater outside. Can you say more about that option? Space is my primary reason for switching.

Many Thanks!

[remodelremodel]

I had a solar hot water heater for 20 years and thought it was great, but when I moved to Washington State from California, I figured solar wouldn't work. I bought an Adtec Electric Tankless. It has 2- 220 electric lines going into it. Unless you have plenty of sunshine, this is the way to go. I have hot water that never runs out. Mine is centrally located and takes the same amount of time to get to the faucet as a regular water heater. Since it's so small you can put it anywhere. When I was in the middle of my total remodel, a long hot shower was my only bright spot. I was told negative things by plumbing stores, ie "When the electric goes out you can't take a shower". I don't usually shower in the dark, so no problem. I've had it for over a year now and I love it. My electric went out for one hour since I've been here. You don't pay for water you don't use. Can't say enough good things about it:-)

[meowkitty]

I very much agree, tankless is the way to go! We started out with a SETS brand electric unit--not the best choice in our opinion...honesty, not the best choice, period (per the husband-figure of the household). We had significant problems with flow and temperature inconsistancy--we ultimately returned it. Our initial choice to go electric was to avoid moving the gas line, however, it was still a pretty good chunk of change to have adequate wiring installed to supply the SETS brand electric model. We've since moved the gas lines and switched to an outdoor natural gas model (Rheem brand)--it is the bomb! It's controlled by a remote control in the house (to set the water temp). We have the temperature set for me--as I take the hottest baths/showers--I merely turn on the hot water spiggot and viola perfect temperature every time. Chuckles, on the other hand has to mix in a little cold water to get his perfect shower temperature. Our unit flows at 5.3 gallons/minute and we have hot water to any faucet in the house in less than 60 seconds. It's consistant and it never runs out...How cool is that!..I definately recommend it!

[my3daughters]

I'm also considering tankless. Currently have a 120 gallon electric which is 12 years old so there will be significant cost savings each year. I called BGE Home yesterday for an estimate. We have gas in the home now so my choices are high efficiency tank or tankless hot water heater using natural gas. I assume I'd have to add a vent for the tankless. The BGE guy said that tankless tends to run $2500-3500 to buy and install versus about $1000 for the tank one. I know that the tankless unit itself runs about $1100 so I guess installation is $1400-2400. Thats a bit steep even if it will save me money in the long run. That sent me back to the drawing board to consider it more. I need to see how long it would take to pay off the difference.

Kate R.

[climber_grrl]

I'll try to answer as much as I can for everyone.

Kelly - What some people do is have a small (like 5 to 10 gallons) reserve tank. It prevents the issue I talked about WRT waiting. By having some water already hot it can shorten the wait time if you only have a tankless. We chose not to do that because I didn't want to have 2 systems for cost, maintenance, and energy efficiency reasons. I also questioned whether it would cause the tankless to not turn on 'cause there wasn't the demand/flow rate. I'm pretty sure that those small reserve tanks can't be used if you want a recirculating pump (a whole other hot water topic).

J - I'm not as familiar w/electric systems as with gas, but I know that gas units can either be purchased as inside, which need venting, or outside versions. What I was hoping you might be able to do is if your current WH is against an outside wall, maybe you could find an outside unit so that you could free up space in the kitchen. Hopefully that's do-able and would only require just a little bit of plumbing re-routing. I don't really know your plumbing or electrical situation so I can't tell you for sure. As remodelremodel mentioned it does require a 220 so you 1st need to find out if you have enough amps left on your service to add another 220 line. You might want to contact a plumber and an electrician to see what kind of options you have. Another thought, are you in a planned community? Do you have strict CC&Rs and architectural review committees? If so, you might be limited in what you can do on the outside of your townhome.

Meowkitty - I think my Takagi has about that flow rate, too, now that it's cold because of the temperature differential between incoming and outgoing water. Even though I live in CA our water is frigid in the winter because I'm not at the beach, but once it's hot, it really nice and there's definitely enough flow to satisfy my high pressure shower desires. Ahhhh.

My3daughters - 120 gallons! Oh my god. You must NEVER run out now. Of course it must cost you a pretty penny to keep all that water hot when you don't need it. The price of the unit sounds about right (although I got mine for just shy of $900 by purchasing it on the web), but that installation cost sounds out of control. Depending on where you place the tankless and how you need to route the venting maybe it makes sense. Because we were remodeling and moving where the HWH lives, we specifically placed it inside a mechanical room, but on an outside wall so that all we had to do for venting was use a 90 degree elbow. Cut one hole, add one elbow. Venting complete. You might want to call some plumbers to get some other quotes for comparison. Oh, the venting pipe itself is fairly expensive 'cause it's specialized, so the more venting you need the more material costs will be. If you give me an idea of where it has to live in your house maybe we can figure out ways to make the venting less of an issue.

Keep the questions coming. No reason to end the conversation now. There's lots more to discuss. Flow rate, temperature differentials, warranties, brands, etc.

[Tigratrus]

What a wonderful collection of useful info!

Added to Important/Useful threads sticky...

I so which we'd gone with one when we redid our system a few years ago. Actually I wish we'd popped for the more expensive geothermal (which can be used to provide free hot water in the summer) rather than air source heat pumps, but tankless seems so much better than tank based in general. How big do they tend to be? It'd be nice to free up some extra floor space...

James

[remodelremodel]

My Adtec tankless water heater is approximately 20" long, 7" wide, 5" deep. It cost $550. and the electrician was another $350. My house was gutted when I bought it, no drywall, no electric, no plumbing. I named my house, "The Big Yellow Crack-House". Because I was starting with a blank slate, it was less expensive and easier to add extras. I also put in a whole house vacuum system with a kitchen baseboard dustpan thing. The vacuum guy was the one who told me about Adtec. I think they are made locally???

[vmole]

Originally Posted by climber_grrl

The price of the unit sounds about right (although I got mine for just shy of $900 by purchasing it on the web), but that installation cost sounds out of control.

That was my first reaction, too, but then I noticed the current heater is electric, and I suspect that part of the tankless installation was running a new gas line, along with the mentioned vent. Depending on where the heater is and where the current gas line is located, it can be pretty easy to rack up two grand worth of plumbing.

Which is not to say that getting a second/third/etc. bid wouldn't be a good idea.