Tankless water heater opinions


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Old 11-25-12, 09:04 PM
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Tankless water heater opinions

Looking for advice on what route to go. I have had too many issues with tanks. After I saw the price on tankless electric tanks, I might go that route. I tried to find guides to them, but I cant find decent info that isnt biased to get me to buy their product.

I have a 2 bath 2 story house, no dishwasher yet, but would like one soon, and 1/2in PVC hot water lines in the house. Is there anything else I need to consider when thinking about capacity of my current lines?

I was thinking nothing lower then 2GPM, but if I go more GPM does that mean I can get a little hotter water? Just looking for advice. I got way too frustrated dealing my old tanks... time just cut my losses and get a real setup that works.
 
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Old 11-26-12, 03:23 AM
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While most on the forum don't advocate switching to tankless, I have a client who had a gas unit installed and it was of sufficient size to handle all they had continuously. Upping the GPM won't get you "hotter" water, just more hot water, faster. I would absolutely not install an electric tankless water heater. Wiring nightmare and a resource hog.

What has been the largest issue with tank water heaters that you had?
 
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Old 11-26-12, 05:34 AM
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They sound good but tankless heaters end up being a good choice fairly infrequently.

In your case, the electrics generally don't provide enough hot water unless you get the really high capacity ones and most houses aren't wired to handle them so the installation gets pretty spendy.
 
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Old 11-26-12, 05:47 AM
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I don't think I would go electric tankless.

I looked into the tank vs. tankless a few years ago (while I was in a natural gas serviced area).
The benifits of tankless is space (mostly) followed by savings if;
- You area small family (single or couple with no kids)
- You are very water conservitive (no big baths regularly, or filling hot tube, etc).
- Do laundry in cold water

If you have a family with kids, I'd suggest going with a tank. I don't remember my numbers from when I looked, but estimating based on everyone having a shower once every 1.5 days (compensate for not days not home or skipped days), a tank was cheaper to own when it was just three of us (wife, myself and our son).
If you do not have natural gas feed to the house, I'd also consider a tank as being the better ROI.
 
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Old 11-26-12, 08:56 AM
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I already have a 50Amp 2 post breaker, and I assume it will run on 10/3 wire. 40$ extra. Its my wife, myself, and our 7mo old child. and we dont use much water. Laundry, yeah very rare for a hot load of laundry. I think everything is warm water when we use it.

We have a Gas line into the house, but I dont quite get how the exhaust works. Do these units come with an exhaust vent like the power vent water tanks? or is it an atmospheric ventilation system?

The whole issue is this. I had a power vent and it died, and I cant use anything but a power vent, or electric, and I am not wired for electric yet ( But I would only need a breaker/wire). Its more expensive anyways, so I was looking into this as an option... Gas or Electric. How big, what type... I have not found enough about them yet to make an educated choice.
 
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Old 11-26-12, 09:16 AM
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I think one point has been missed....PVC hot water lines? AFAIK thats not even allowed by code most places.

As to your electric....most tankless whole house units require 2 or more feeds of 40-60 amps. The smaller undersink/point of use types use less.

Here's a spec page for reference...this is Rheem...but they will all be similar. http://www.rheem.com/documents/rte-2...ric-spec-sheet
 
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Old 11-26-12, 09:27 AM
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Just my own experience. We have 2 of them in our recently purchased house. The main problem with tankless is the location of the tankless unit. Depending on how far away, you get a cold "purge" of water - that is, the amount of pipe water travels through before you get actual hot water. In our case it takes literally 3 mins for HOT water to make it to the far end of the house. It takes a little over 2 mins. for the shower to get hot .. So this is a waste of water obviously. They sell "recirculation" systems whereby hot water is always circulating around until you need it .. But of course that consumes more gas and from what I've been told reduces the lifespan of the Tankless unit. So buyer beware ... good luck
 
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Old 11-26-12, 09:40 AM
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It can take a long time for the cost of the install infrastructure such as high temperature vent piping and new higher volume gas supply piping to be paid off based on the small amount saved on operating cost.
 
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Old 11-26-12, 09:43 AM
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Early morning showers, usually take 8-12 seconds to get hot water from the tank to the shower head. Not really an issue. Our house is pretty small. 1300 SQ Ft.

I say PVC, but technically its CPVC pipe. Does that make a difference? This is North Dakota after all. People here STILL dont know you can get cash back on debit card purchases... >.< (And in fact its so backwards here that by default all cards are run as credit) So it would not surprise me if PVC is allowed.

I am starting to think gas is the way to go. We have cheap rates here compared to back in Idaho where we moved from, so now I just have to figure out if I can use the PVC exhaust from my power vent or if I have to dismantle my wood stove and cap it and use that flue for the Gas exhaust.

*EDIT*
Just saw your post ray, if it is going to require high temp piping, the old PVC exhaust line wont work. Looks like we dont have a wood stove anymore
 

Last edited by Sedare; 11-26-12 at 09:45 AM. Reason: Someone else posted while I typed.
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Old 11-26-12, 09:55 AM
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Ahhh CPVC is fine...thats what's allowed.
 
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Old 11-26-12, 10:18 AM
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Ok so basically, I can choose from replacing my current power vent gas water heater with another power vent system, or move to a gas tankless with 3GPM 90 DEGREE RAISE. City water here in North Dakota is 41 degrees from the pipes.
I am starting to lean back towards a tank...
 

Last edited by Sedare; 11-26-12 at 10:19 AM. Reason: Evidently english is my 17th language?
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Old 11-26-12, 10:39 AM
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I am starting to lean back towards a tank
Yeah, you won't be the first or the last to think tankless and then go this way. They sound like a better option than they really are for most people.
 
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Old 11-26-12, 10:47 AM
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And remember....a tankless will normally require larger gas supply lines than a typical storage heater. Gotta have those BTUs ya know? At least I think they do.

And as was mentioned...unless you go with a condensing type (more $$$) you need the high temp flue piping. And even with the condensing unit it needs 2 pipes which complicates things.


I just don't think they are a good option for most people as a retrofit, unless installation circumstances and lifestyle fit perfectly.
 
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Old 11-26-12, 12:38 PM
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I already have 1in gas line 5 feet (linear) from where I would be placing the unit.I would only need to swap the 1/2 inch to 1 inch, at current prices, Im looking at 40-50$. Weekly, we dont use hot water apart from morning showers 3 days in a row. 3 days out 4 days home. So all that time a tank is heating is wasted. A power vent system is going to run me 800-1200 depending on what I want.

So right now the determining factor is this. Can I use my current wood burning stove flue for the exhaust for this (AFTER I TAKE WOOD STOVE OUT) and seal the holes, and run a high BTU gas tankless system? Will my flue support this????? How can I tell what is in my flue?
 

Last edited by Sedare; 11-26-12 at 12:41 PM. Reason: Added question.
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Old 11-26-12, 12:53 PM
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The tankless are flue specific. Most likely you will not be able to use the stove flue.

The gas line needs to support the BTU's of the unit. Most good units are at least 199,000 btu. I doubt where your old heater was hooked up, the gas line would be insufficient.

Best to tap off the meter and run a home run to the unit.

Again cost will be more like the $3000 range when all is said and done. Again IMO I would be putting another power vent in as you had before.

But its your home. I could tell you that most are unhappy with their tank less units.
 
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Old 11-26-12, 01:16 PM
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is that 3000 for someone else installing it? or is 3000 in just parts? How expensive is that flue piping?!?! Now I am about ruling it out, but I have to ask now because if these units ever get cheap, or we move to a different house, I want to know my options.
 
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Old 11-26-12, 03:18 PM
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Depends on the unit. Link to a unit you are considering and I can give you a rough ideal of the cost involved for DIY.
 
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Old 11-26-12, 04:47 PM
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Flue piping here for a tankless unit runs $65 per 2' section. Our gas company installs the units and hooks them to the propane tank, but you still have the plumbing to deal with, as well as an electrical receptacle for the brains. DIY, yeah.
 
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Old 11-26-12, 09:52 PM
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I wont waste anymore of your time. If I have to get a unit that would have to raise the water 75-80 for a Shower, with a head that is already going to require 2.5gpm, then I am looking at close to 1000$. Then there is the piping, flue modification, electronic wiring, and redoing my PVC in the basement to fit. We are going to just get a new Power Vent heater and put it in place of our old one. It was nice to think about it, but right now and for where we live (water temp wise) its just not feasible.

Thanks for the help everyone.
 
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Old 11-27-12, 02:50 AM
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Sorry it didn't work out, and we couldn't be your cheerleaders, but from our experience, the initial cost of the units aren't returned well enough, and they are expensive. Good luck with the project, and let us know if we can help on anything.
 
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Old 11-27-12, 06:02 AM
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Don't worry, you didn't waste anyone's time. We're here to help make sure you have all the information so you can make the best decision for yourself and I think that's what happened here.

Sorry we ended up steering you away from your initial plans but these heaters are a lot better in theory than practice.
 
 

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