Replacement Hot Water Heater

[travelover]

..........Option 3 will have zero maintenance issues and use no electricity. Depending on where the present pump recirculates "to", it might be fairly easy to give it a try just by removing the pump and inserting a "T" fitting in its place (as suggested by Travelover).
...........

It occurs to me that these pumps are often plumbed so they just dump water from the hot line into the cold line, at the farthest point. If this is the case here, you'd need to add a return line or stick with a pump.

 

[Texas Proud]

As someone else pointed out... and I had forgotten about it... the gas heaters are pretty loud...

Mine had a 3/4 inch gas line... and when it turned on it was a big WHOOSH.... and it stayed kinda loud... but, it was in my garage and I only heard it inside in the half bath that was on the other side of the wall...

As for how long they are supposed to last... well, 20 years or more... not that you will be trouble free for 20 years, but the things are pretty well built...

 

[samclem]

It occurs to me that these pumps are often plumbed so they just dump water from the hot line into the cold line, at the farthest point. If this is the case here, you'd need to add a return line or stick with a pump.

If so, you still might not need to go all the way back to the WH with the return line, right? The return line could dump into any convenient cold water line (at least one where having warm-ish water come out of the cold tap would be acceptable) provided 1) there was a significant difference in height (a couple of stories?) and 2) a significant difference in temperature between where the water started its trip and where it ends. At least I think that would work.

 

[Hyperborea]

I installed a catch pan under my heater with a pipe to a floor drain. That way if and when the tank leaks, it does not flood the basement.

That is not just a good idea but depending on where the water heater is located it is current building code too.

 

[ERD50]

Not intending to hijack this thread but this is still about water heaters. Maybe it will help someone.

A few years ago, my ~5 year old water heater started to leak at the high pressure valve. I changed the valve (simple job) but the new one started leaking too (within a few minutes). I changed it several more times and they all kept dripping. OK, after a few months, I replaced the water heater. Guess what, the new one started leaking at the valve too. (WTF) Then I started reading a lot about water heaters, troubleshooting and how they really worked. In the end, I installed a ~2 gallon expansion tank and that fixed the problem.

"Apparently" about the time this problem started, my local water supplier had significantly raised the water pressure and installed check valves in their local distribution pipes and never told anyone.

The water heater at DD's house started leaking (not through the pressure valve, as far as I could tell). There was a separate small valve with nothing connected. After some research, I found that they probably had an expansion tank connected there at one time. They are on city water, and there is normally a check valve at the supply, so there is no chance of back-feeding the supply. But that also means that when the water in the tank is heated, it expands, and puts pressure on the system. So even if this isn't enough to trip the safety valve, it could be approaching that level ( ~ 150 PSI!), that has to shorten the life of a water heater.

I am on a well, and well pumps have fairly large expansion tanks ( 10G or more), so that the pump can cycle on/off at reasonable duty cycles. So my water heater never has seen more than 60 PSI. On the other hand, it cycles a dozen times a day between 45 and 60, so I wonder if that results in some flexing type strain?

Bottom line - if you are on city water, consider an expansion tank and make sure it maintains some air in it. Newer ones have a bladder, so should last a long time. Older ones were just an air space, and the water would absorb the air over time, 'water logging' the tank.

-ERD50

 

[mystang52]

And while I'm doing this, should I install a water softening system as well? I assume we have hard water as I see crusty deposits all over the fixtures and lots of green stuff that has built up over the years as well. We live at the beach, so some of it may be the salt in the air, if that makes any difference.

Thanks!

First, let me echo the other responder - you want a water heater, no need for a hot water heater To your other question, if money is not a major issue I heartily recommend a water softener. It appears you have hard water (this can be tested for verification). You will see cleaner dishes with a water softener, none of that hard water crud you referenced, feel cleaner after a bath or shower. Where I live it was a no-brainer, as we definitely have hard water and the softener makes a huge difference.

 

[Walt34]

To your other question, if money is not a major issue I heartily recommend a water softener. It appears you have hard water (this can be tested for verification). You will see cleaner dishes with a water softener, none of that hard water crud you referenced, feel cleaner after a bath or shower. Where I live it was a no-brainer, as we definitely have hard water and the softener makes a huge difference.

Whether a water softener is needed depends very much on the area. When we lived in the D.C. area there was no need for one. I was in my mid 20's before I ever knew such a thing existed.

When we moved to WV the glassware stated getting grungy within weeks and having a water softener fixed that issue.

I'd suggest getting the water tested or get a DIY test kit from a hardware store. It's not hard to do, takes 10-15 minutes.

 

[MichaelB]

I'd suggest getting the water tested or get a DIY test kit from a hardware store. It's not hard to do, takes 10-15 minutes.

We get municipal reports with a detailed analysis of our water. I think it's yearly ..

 

[travelover]

If so, you still might not need to go all the way back to the WH with the return line, right? The return line could dump into any convenient cold water line (at least one where having warm-ish water come out of the cold tap would be acceptable) provided 1) there was a significant difference in height (a couple of stories?) and 2) a significant difference in temperature between where the water started its trip and where it ends. At least I think that would work.

Dunno. It would seem that if you turned on the hot water full blast, you might get a reverse flow in that return line fed from the cold water line. My only experience is with the return to the bottom of the hot water tank.

 

[jzajzz]

Our hot water heaters are 15 years old and ready for replacement. We have two 40 gallons heaters, which seems like overkill for just the two of us. I've been reading about the tankless water heaters and opinions seem to be equally divided over whether to go with them or stay with traditional models. Our home is three stories, and we've always had problems with the hot water taking a long time to get to the third floor shower. We did install a recirculation pump 15 years ago, and I think it generally worked fine. But it rusted out years ago and so we haven't been using it any more.

What have other people experienced with tankless versus tank heaters? And while I'm doing this, should I install a water softening system as well? I assume we have hard water as I see crusty deposits all over the fixtures and lots of green stuff that has built up over the years as well. We live at the beach, so some of it may be the salt in the air, if that makes any difference.

I know nothing about plumbing and am reluctant to just take the advice of the local plumber without getting some input from others.

Thanks!

There are great incentives in my state to purchase tankless water heaters. Sounds like you're in CALI . .i think they give you back $800 for switching to tankless.

Tankless heaters are not as efficient in colder climates but you're in Cali ..so it's a no brainer. The installation cost might be a deterrent because you probably will have to reconfigure your plumbing while you can just plug in a new 40 gallon water heater.

The benefit of tankless water heaters is that it heats up the water on demandas opposed to holding a tank of hot water that has to be kept hot. The downside is that when too many fixtures are using hot water at the same time, it won't perform as well. So the more bathroom you have in your house the more you should think about oversizing.

 

[ERD50]

... ..so it's a no brainer.

The benefit of tankless water heaters is that it heats up the water on demandas opposed to holding a tank of hot water that has to be kept hot. ....

Is it really a "no-brainer"? My brain, and my limited knowledge of physics says that it takes zero energy to keep hot water hot. It only takes energy to raise the temperature, something that both types need to do.

Now, in the real world, there are losses through the tank to the outside environment, and those losses must be made up. But modern tanks are well insulated, these losses are pretty minor.

Please provide Energy Star numbers on a comparable tank and tankless for the same annual consumption. And then we can use our brains, and a calculator to see how much sense it makes.

-ERD50

 

[jzajzz]

Is it really a "no-brainer"? My brain, and my limited knowledge of physics says that it takes zero energy to keep hot water hot. It only takes energy to raise the temperature, something that both types need to do.

Now, in the real world, there are losses through the tank to the outside environment, and those losses must be made up. But modern tanks are well insulated, these losses are pretty minor.

Please provide Energy Star numbers on a comparable tank and tankless for the same annual consumption. And then we can use our brains, and a calculator to see how much sense it makes.

-ERD50

The tank type water needs to raise the temperature ... then when the water temp drops again , it would need to keep raising it even when the water heater is not in use.

 

[jzajzz]

Is it really a "no-brainer"? My brain, and my limited knowledge of physics says that it takes zero energy to keep hot water hot. It only takes energy to raise the temperature, something that both types need to do.

Now, in the real world, there are losses through the tank to the outside environment, and those losses must be made up. But modern tanks are well insulated, these losses are pretty minor.

Please provide Energy Star numbers on a comparable tank and tankless for the same annual consumption. And then we can use our brains, and a calculator to see how much sense it makes.

-ERD50

As you can see on this chart the Energy factor on a tank type water heater is about .67

EF for tankless types are .90 +

https://www.energystar.gov/products/water_heaters/residential_water_heaters_key_product_criteria

 

[ERD50]

As you can see on this chart the Energy factor on a tank type water heater is about .67

EF for tankless types are .90 +

https://www.energystar.gov/products/water_heaters/residential_water_heaters_key_product_criteria

No, I can't see that. Those are the ratings required for Energy Star approval. A very different thing.

I asked for " Energy Star numbers on a comparable tank and tankless for the same annual consumption." I've got one so far, for a basic NG water heater, just a flu damper, nothing more fancy than that ...

214 therms ~ $261 based on their 'standard usage' model.

Maybe you can beat me to a comparable tankless (the Sears site didn't seem to have it on theirs)?

wait - something odd with the attachment - it seemed to try to access my hard drive, even though I uploaded it through the attachment process?

see if this link works:

http://c.shld.net/assets/docs/spin_prod_882469412.pdf

-ERD50

 

[meierlde]

Here is a link to how the energy factor is derived :https://en.wikipedia.org/wiki/Energy_factor

Note that the reason gas looks lower is that there is combustion involved whereas the actual heating of water is 100% efficient i.e. all the electricity that goes into the heating element goes into the water. Combustion involves some heat loss in the exhaust gas stream.

 

[meierlde]

No, I can't see that. Those are the ratings required for Energy Star approval. A very different thing.

I asked for " Energy Star numbers on a comparable tank and tankless for the same annual consumption." I've got one so far, for a basic NG water heater, just a flu damper, nothing more fancy than that ...

214 therms ~ $261 based on their 'standard usage' model.

Maybe you can beat me to a comparable tankless (the Sears site didn't seem to have it on theirs)?


-ERD50

Go to say the Rheem site and you will find a listing of their water heaters and their energy factors. here is a link to AO Smith's web site, they list their models and their energy factors. Gas seems to be around .7 where as electric is .95.
BTW modern gas water heaters now need 110 v service to run their blowers and ignitors just like modern furnaces do, the days of the pilot light are over.

 

[ERD50]

Here is a link to how the energy factor is derived :https://en.wikipedia.org/wiki/Energy_factor

Note that the reason gas looks lower is that there is combustion involved whereas the actual heating of water is 100% efficient i.e. all the electricity that goes into the heating element goes into the water. Combustion involves some heat loss in the exhaust gas stream.

No, you need to compare NG to NG and electric to electric. -ERD50

 

[ERD50]

OK, a better comp, both at home depot, both Rheem:

Rheem Performance 40 Gal. Tall 6 Year 36,000 BTU Natural Gas Water Heater-XG40T06EC36U1 - The Home Depot

Rheem EcoSense 8.4 GPM Natural Gas High Efficiency Indoor Tankless Gas Water Heater-ECOH160DVLN-1 - The Home Depot

$1201 for tankless, $398 for tank.

Annual cost for NG - $178 tankless; $263 tank

Assume you already have gas pipe sized for a tankless, and no extra install cost, that's a $803 upfront cost. Divide by the $85 annual delta, and it is a 9.5 year payback - throw in a conservative 3.5% investment return on your portfolio ( .035 * 803 = $28), and that takes the savings down to $57, and payback to 14 years.

My tank water heater was still good at 30 years.

Took a little brain power to figure that.

-ERD50

 

[meierlde]

No, you need to compare NG to NG and electric to electric. -ERD50

It depends on why you are making the comparison. For example if I take electric and a 15% renewable factor combined with the best combined cycle gas power stations I get about .62 heat factor including generation. or about .54 if you use only combined cycle gas power.
Note that for electric there is essentially for new water heaters only .95 as a heat factor, whereas for gas you have the same sorts of questions that you have with a gas furnace about condensing or non condensing combustion, (although you probably have a drain near the water heater).

 

[mpeirce]

We replaced our two conventional water heaters about six years ago with a Navien 98% condensing natural gas tankless unit (w/ EF .95) This very high efficiency unit cost us about $3K installed (w/ some kickback - I don't recall how much) and replaced two 50 gal conventional units.

Technically it's not 100% tankless as there is a tiny "buffer tank" that keeps a small amount of hot water. Many tankless units can send a small amount of cold water when they start up - imagine the lines have hot water in them, you turn on the hot water, it starts flowing, a small amount of cold water flows through the unit as the NG fires up to start heating the water. They call this a "cold water sandwich". Anyway buffer tank unit eliminates that problem.

The unit also includes a recirculation pump for "instant hot water", but we haven't hooked that up since it leaks some heat.

One benefit of units like this is that with the heat recovery technology they use, the exhaust gases aren't very hot. In fact there is no real flue, just a PVC pipe that can be vented directly outside. I stuck a thermometer in the air flow and it was around 110°F.

We took the opportunity to install the new water heater on the same side of the house as all our bathrooms and kitchen to cut down on the time it takes the hot water to arrive. Our house builder located the original water on the far side of the house - where the utilities come into the house to make it easy for him.

Our gas service was fine, but older homes may need a larger gas line to supply the needs of the unit.

We've been quite happy with it. No problems in six years. Plenty of water for more than one person showering at once - even if the washing machine is running.

 

[ERD50]

The tank type water needs to raise the temperature ... then when the water temp drops again , it would need to keep raising it even when the water heater is not in use.

Sure, but that water tank only loses a few degrees overnight, or between firings. Occasionally having to raise it 5 degrees, versus the initial 70 degrees or so, is a big difference, as I'm sure you understand.

I gave you the numbers - what else is there to say about it?

It depends on why you are making the comparison. ...

Yes, but for most people, the N-Gas or electric (or maybe propane) decision is made by what is available to them. So I think for the homeowner, the comparison is NG-NG and electric-electric.

-ERD50

 

[samclem]

OK, a better comp, both at home depot, both Rheem:

. . . $1201 for tankless, $398 for tank.

Annual cost for NG - $178 tankless; $263 tank

Assume you already have gas pipe sized for a tankless, and no extra install cost, that's a $803 upfront cost. Divide by the $85 annual delta, and it is a 9.5 year payback - throw in a conservative 3.5% investment return on your portfolio ( .035 * 803 = $28), and that takes the savings down to $57, and payback to 14 years.

And those Energy Star labels/comparison assume a use of 64 gallons of hot water per day for 365 days per year. That's a lot for a two person household (per the OP).
At more realistic usage rates for a couple, the payback for the tankless unit would be longer still. And we've assumed zero maintenance costs--reasonable for a conventional holding tank unit, maybe less likely for the tankless unit.

 

[Rambler]

We have two tankless water heaters in our home...one for each end of a pretty big home. When I had the home built, I more or less specified the water heaters I wanted...capable of high output so that multiple showers could be going at once. The problem is that with today's low flow plumbing fixtures, the hot water has to be all the way on for them to kick on. If you have a single lever fixture, then the moment you start turning the heat down, the water heater detects an overheated situation, and kicks off. So, what I've had to do is turn the temp down to about as low as I can get it on the water heater control panel, do I don't have to back off the heat much on the single lever fixtures.

We bought a home in NV a couple months ago, with a 50 gallon tank and a recirc pump. We love it. Never run out of hot water, and when we turn on the faucet, the water is hot in seconds instead of minutes. As we age, I think we'll be fine with a slightly higher gas bill in exchange for plenty of hot water, pronto.

 

[homestead]

Looked at my 50 gal water heater saw date of 1992 so 25 years old.
Still had the 6yr warranty sticker on it. So when it goes will try to find
another one locally. Brand is US Craftmaster.

 

[jzajzz]

FYI ... the way to make your water heater last a lot longer than the warranty period is to replace the anode rod every couple of years ... the difference between the 5/6 yr warranty heater vs the 10/12 yr warranty heaters .. is that the ladder has 2 anode rods as opposed to 1.

The anode rod is the piece that attracts all the minerals and all the residue that will harm the lining of the tank.