Tankless Water Heater - Struggling to Justify

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wilked
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Tankless Water Heater - Struggling to Justify

Post by wilked »

We are adding a new master bath, increasing total baths to 3. The new bathroom will have a shower and a soaking tub, ann the tub itself will be ~ 50 gallons.

I currently have a 40 gal gas-fired Bradford White water heater. ~8 years old, no issues with it, anode replaced 2 years ago (was 60% spent).

My original plan was to add a second 40 gal water heater and pipe them in parallel, thus becoming an effective 80 gal tank. A new unit is about $650 and install might be $500-1000.

I had a plumber come by that I like, he was strongly advocating tankless. $3200 installed (Rennai), with $700 rebate from the state. ($2500 effective).

My basement is unfinished, I have plenty of floor space, and I also have a Moen Flo which will shut the water supply off on a detected leak.

My understanding of the tankless, and my thoughts on it:
*Unlimited hot water! - Why would I want this? I don't want unlimited, I only want 'enough'. With our current 40 gal heater unless we take back-back-back showers we don't run out. I think it's happened twice. With 80 gal I think it'd be extremely difficult to run out.
*More efficient energy-wise - Our gas bill is very low in the summer (when we're not using it for heat), maybe it's $25/month? I could maybe see $100/yr savings here, which is not enough to account for the additional upfront cost.
*Takes up less room - Not important to me with a big unfinished basement
*Requires annual flushes and 5 year full maintenance - Not too big a deal, but is more than I do with the tanks
*Will be slower to get hot water, maybe 40 seconds - This might be frustrating. I know you can add things like circulation loops / etc but that is more complexity and money.

---------
I want to talk myself into it to be honest, but it seems like a loser on paper. Am I missing it? Is the selling point of 'unlimited hot water' really that exciting?
slidecreek
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Re: Tankless Water Heater - Struggling to Justify

Post by slidecreek »

40 seconds? When I got a tankless, it was maybe a second or two slower to provide hot water. They heat up fast.

Biggest selling point for me was how they fail. A tankless failing typically mean no hot water. A tank failing can flood your basement.
neilpilot
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Re: Tankless Water Heater - Struggling to Justify

Post by neilpilot »

Unless you spend extra for a battery backup, the tankless heater's controls will not function if your electricity goes out. The basic Bradford While gas heater doesn't use an electrical power source.
JPM
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Re: Tankless Water Heater - Struggling to Justify

Post by JPM »

We had tankless installed in our big suburban house for about 8-9 years before we moved and again installed new in our downsizer.

We liked the instant and unlimited hot water, but we had a circulator in the big house. In the smaller house, hot water takes a half minute to reach the shower but no big deal to us. It took awhile for hot water to reach the third floor shower, so we needed a circulator.

Biggest problem with Rinnai was getting service. The original installer went bust and we had to cast about for service. After a little teaching from the service tech, I was able to troubleshoot most problems myself.

Now we have an AO Smith, recommended by our plumbing contractor who services the brand.
Globalviewer58
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Re: Tankless Water Heater - Struggling to Justify

Post by Globalviewer58 »

What cost for heated soaking tub? This allows conserving energy until you are using the tub.

Our soaking tub was already installed when old 40 gallon water heater was replaced with 50 gallon unit. If soaker had a heater we could have replaced with 40 gallon unit.
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lthenderson
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Re: Tankless Water Heater - Struggling to Justify

Post by lthenderson »

For me, the biggest downside was the unknown life expectancy and still is to some extent. Back when I was looking at them, they were three times the cost of a normal tank water heater and I generally get 15 years out of a water heater meaning to recoup the cost I would need closer to 35 or 40 years use (figuring in some cost savings) out of a tankless unit to get my money back. They are more physically sophisticated than there tanked brethren and advertised the same 15 year life span. Even now most only say they will average 20 years and they are still more than double the price of a tanked one. Figuring in cost savings, they are probably getting close to being a wash money wise.

But since you are questioning a tankless versus two tanked, I'm guessing there might be more of a cost savings in this particular case going with tankless.

Note: Tankless need to be located on outside wall or have a forced vent to pipe it to the exterior which is another device inline that has moving parts that can go wrong. Something to think about.
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jabberwockOG
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Re: Tankless Water Heater - Struggling to Justify

Post by jabberwockOG »

Very long payback if you already have a functioning hot water heater. Our electric 50 gal hot water heater costs about $30 month to operate. There is no reasonable payback period that doesn't exceed the average service life of the new heater that would justify replacing a functioning water heater (even supposed high cost electric one) with a tank-less water heater. In my location even in a situation where the old electric heater was broken the payback period for installing a tank-less (high install cost in my area) instead of old school tank water heater is still questionable.
quantAndHold
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Re: Tankless Water Heater - Struggling to Justify

Post by quantAndHold »

We looked into tankless, and couldn’t justify the cost. It was expensive, and the payback period was going to be longer than the expected life of the heater.

At the time we were researching, the local utility was pushing people to go with solar hot water systems. They were even more expensive to buy, but then your hot water bill would go to zero. Basically, you have a more or less normal hot water tank, which is heated by panels on the roof with some sort of recirculating pump. As an empty nest couple, we didn’t use enough hot water for that to be cost effective either, but for a family with kids, it seemed like a reasonable deal.

So we still have a normal 40 gallon tank.
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momvesting
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Re: Tankless Water Heater - Struggling to Justify

Post by momvesting »

We came to the same conclusion you did. We had an older 40 gallon when we moved in, but the master bath has an oversized tub and the 40 gallon would run out before you could entirely fill the tub. Also, like you, our gas bill runs $15-20 in the summer and almost half of that is service fees, so we just didn't see the financial payback. We got a 50 gallon with a faster refresh rate, which means it can do 80 gallons of hot water without interruption. We have had it a little over a year and have not yet run out of hot water. However, we still do some of the same things to space out usage that we did with the 40 gallon, such as loading the dishwasher at night and putting it on a 4 hour delay so it won't start until long after everyone has showered and gone to bed. We also have a delay on our washing machine that we use occasionally, but some of this is because although we have plenty of hot water, we don't have plenty of pressure.
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wilked
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Re: Tankless Water Heater - Struggling to Justify

Post by wilked »

slidecreek wrote: Mon Mar 29, 2021 3:26 pm 40 seconds? When I got a tankless, it was maybe a second or two slower to provide hot water. They heat up fast.

Biggest selling point for me was how they fail. A tankless failing typically mean no hot water. A tank failing can flood your basement.
I think if I had a finished basement then no question - get the tankless heater. A leak would be a little messy for me but not a big deal as most everything, including anything important, is off the ground
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wilked
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Re: Tankless Water Heater - Struggling to Justify

Post by wilked »

momvesting wrote: Mon Mar 29, 2021 4:06 pm We came to the same conclusion you did. We had an older 40 gallon when we moved in, but the master bath has an oversized tub and the 40 gallon would run out before you could entirely fill the tub. Also, like you, our gas bill runs $15-20 in the summer and almost half of that is service fees, so we just didn't see the financial payback. We got a 50 gallon with a faster refresh rate, which means it can do 80 gallons of hot water without interruption. We have had it a little over a year and have not yet run out of hot water. However, we still do some of the same things to space out usage that we did with the 40 gallon, such as loading the dishwasher at night and putting it on a 4 hour delay so it won't start until long after everyone has showered and gone to bed. We also have a delay on our washing machine that we use occasionally, but some of this is because although we have plenty of hot water, we don't have plenty of pressure.
Could you PM me the make/model? Thanks
Sage16
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Re: Tankless Water Heater - Struggling to Justify

Post by Sage16 »

When our 40 gal hot water heater went out in our garage we went to a tankless. The 40 didn't provide enough hot water for our household. The tankless is nice, endless hot water. We had them also put in a recirculate line in the crawl space under the house to our kitchen so it only takes 2 secs at most for hot water at the kitchen sink. Maybe 10 - 15 seconds to get hot water in the showers upstairs. Two downsides to the tankless so far, it is expensive up front vs a regular water heater and everyone is now taking longer showers.
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Californiastate
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Re: Tankless Water Heater - Struggling to Justify

Post by Californiastate »

The gas line and flue would probably need to be changed to add an additional water heater. An upgrade to a 50 gallon might work with the existing.
The plumber is hard selling the tankless because he’ll make bank changing the gas line and flue.
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runner26
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Re: Tankless Water Heater - Struggling to Justify

Post by runner26 »

I was forced to have a tankless installed in my new 2015 construction (ca law). Builder put in a Rinnai. 2018 flush valve developed pin hole leaks. Fought with builder and got them to replace it. 2021 bypass valve shutoff handle metal had dissolved and broke off. Builder would not replace again and it cost $300 to have it replaced. While replacing the valve a leak started in the rinnai. Turned out all the o-rings in the lower half of the unit were failing. This resulted in another $200 repair.

In my prior house I only spent $75 in 15 years on my tank water heater to replace the anode and it was still fine when I sold the house. I was able to do my own labor.

Plumber told me Rinnai tech service is the best for quick responses. Others can keep them on hold for 20 mins. I observed the calling rinnai twice while at my house and they got immediate answers.
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Re: Tankless Water Heater - Struggling to Justify

Post by Gadget »

We've had a Rinai tankless for about 12 years now. No issues other than it doesn't work when power goes out.

Overall I'd do the same if building a new house from scratch. I think it saves us about $20/month when I did the math comparison of natural gas bills. It's pretty convenient having endless hot water in a house full of girls.

It is slightly annoying that it takes longer to get hot water. Although our issue is more of that we have home run lines on every water line, and they take forever to clear all the water. We got around the issue by having a mini 2 gallon hot water tank under the kitchen sink. Everywhere else I'm fine waiting for hot water.
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Re: Tankless Water Heater - Struggling to Justify

Post by suemarkp »

I'm thinking of putting in a small tankless (one that will do 3 to 4 GPM, 2.5 in winter with 110F output) but feed that into the input of a standard tank type water heater. The tank type will act as a buffer when other short duration things want hot water during a shower, like the washing machine, dishwasher, or other sinks.

My existing 50 gal water heater doesn't have the capacity to fill the soaking tub, and back to back showers can be a problem if I go first. My tank water heater is direct vent and you have less choices of sizes, recovery rates, etc and they are quite expensive. I'd change that water heater to tankless, but the gas pipe won't do over 100K btu so it needs to be a smaller unit (and they cost less too). This would fill the soaking tub as long as no other showers are going on at the same time.

I'd also add an electric tank type heater since I'd lose the wall space to vent a gas one and don't have enough gas supply for it. But it will be filled with hot water from the tankless except when demand is so high its output temp drops to 80F or 70F or 60F... So the tank is a buffer to deal with peak demand and the tankless gives hot water forever if the use is low. As long as that high demand doesn't suck everything out of the 40 gallon electric tank, I think this will work.

You could argue it is the worst of both worlds from a leak point of view, but it does allow hot water if either fails (just bypass the bad one). The tankless isn't going to save you any money unless you go weeks to months of using no hot water (e.g. a vacant 2nd home). It is more of a luxury item, and if you don't have enough hot water now it may cost you more because now you can have as much hot water as you want.

Finally, look at the true heating ability of the tankless -- they seem to assume rather warm water in their GPM ratings. If you have cold water (e.g. 40F) in winter, and you want 110F showers, you need to raise the water 70F. It probably won't do that at its "rated" GPM but only at some lower flow rate. What is the worst case GPM need that could happen? If you have 2 showers going and kick in the washing machine, it may not be enough. If you exceed its GPM and delta T rating for very long, the temp of your shower is going to noticeably drop.
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rob
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Re: Tankless Water Heater - Struggling to Justify

Post by rob »

suemarkp wrote: Mon Mar 29, 2021 7:08 pm I'm thinking of putting in a small tankless (one that will do 3 to 4 GPM, 2.5 in winter with 110F output) but feed that into the input of a standard tank type water heater. The tank type will act as a buffer when other short duration things want hot water during a shower, like the washing machine, dishwasher, or other sinks.
I have no idea but logically.... wouldn't it be better on the output side of the traditional tank? When you had capacity it would be pass-thru but when the traditional was running colder it would cut in and add the last part of the heat to bring up to final temp.
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Dave55
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Re: Tankless Water Heater - Struggling to Justify

Post by Dave55 »

I had a Takagi Tankless water heater installed in my old house in CA. Never had a problem with it for the 8 years I lived there. My plumber who recommended it and installed it said he had been installing them for many years and he found them to be very reliable.

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JonnyDVM
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Re: Tankless Water Heater - Struggling to Justify

Post by JonnyDVM »

Tankless is ok. We had two 50 gallons in tandem with a recirculater which we replaced with a tankless a couple years back. The water was getting quite brown and they needed to be replaced but I liked them because the water was magically instantly hot. The tankless takes a few seconds. The biggest advantages to a tankless system as already mentioned are it won’t ruin your basement if it fails and the space savings. All the plumbers swear by them. Maybe that’s because tankless are more profitable for them to install, but I genuinely think it’s because they are the superior system. I’ve known people who’s basement was ruined by a faulty hot water tank. It’s not that uncommon.
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suemarkp
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Re: Tankless Water Heater - Struggling to Justify

Post by suemarkp »

rob wrote: Mon Mar 29, 2021 7:29 pm I have no idea but logically.... wouldn't it be better on the output side of the traditional tank? When you had capacity it would be pass-thru but when the traditional was running colder it would cut in and add the last part of the heat to bring up to final temp.
I dont think so. These are intended to receive cold water. It can throttle the gas heat but only so much. I think any flow will trigger it but i doubt it would turn the gas off if it is heating too much. Maybe it would shutdown on error, or just send out water that is too hot.

Also for me, heating is cheaper with gas than electric, so i want hot water to fill the water heater tank when possible.

Finally, tankless units can have little spurts of too hot or too cold water. There is a mini tank inside of them to moderate this, but putting a huge tank after makes this a complete non issue.
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peetsperk
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Re: Tankless Water Heater - Struggling to Justify

Post by peetsperk »

The biggest threat to any tankless water heater is harder water. It can shorten the life significantly. One other option would be to replace your current water heater with a 75 gallon energy efficient tank unit. You won't have to pay additional plumbing fees to add second water heater, you can get rid of the smaller less efficient unit and you have enough hot water for your new spa tub. Just a thought.
jt90505
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Re: Tankless Water Heater - Struggling to Justify

Post by jt90505 »

I don't think you buy a tankless for return on investment. You have a 40G soak tub, and if you soak for a half hour or so you probably will want to refresh the hot water. Since presumably you want to soak to relax, do you really want to be managing hot water usage to make sure you can enjoy your bath?

We've had a Noritz tankless for about a dozen years without a problem. Its been flushed twice. If sized correctly you will not have spurts of hot/cold water. The tankless is adjacent to our 2 bathrooms so we have hot water in seconds without recirculation or other complexities. We are happy with our decision, it may not be the right choice for you.
Soon2BXProgrammer
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Re: Tankless Water Heater - Struggling to Justify

Post by Soon2BXProgrammer »

i have an older version of:
https://www.takagi.com/products/tankles ... tk-310c-ni
I really like it. Takagi is a brand you will find at plumbing supply stores, not at HomeDepot/Lowes

i picked the 190k noncondensing over the 199k condensing so i didn't have to deal with a drip line.
Aku09
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Re: Tankless Water Heater - Struggling to Justify

Post by Aku09 »

100% I would do tankless in every house I have from here on out. My water heater went out about 2.5 years ago (started leaking from the bottom of it in the middle of
The house) and called around and got some quotes. I think it was around $3200 all said and done to take out the old one which was electric and install the gas tankless underneath the house in my crawl space.

Having 3 kids we would run out of water frequently. Also, my master bath has 3 shower heads in it and anytime we used them all it would run out of hot water within minutes. Now I can keep them all on for as long of a shower as I desire. My water bill has gone up from the more water I’m using, but switching from an electric water heater to a gas tankless I actually ended up saving some money in utilities.
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bottlecap
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Re: Tankless Water Heater - Struggling to Justify

Post by bottlecap »

The biggest annoyance is the 40 to 60 seconds it takes to get hot.

If the expense is close (as it might be with a direct vent), you can try the tankless. Otherwise get an inexpensive tank.

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Re: Tankless Water Heater - Struggling to Justify

Post by finite_difference »

In places with less plentiful water, I could see tankless conserving water since you don’t need to wait for it to get hot.

I like cooking with NG but going all electric w/ solar and ditching the leaky NG infrastructure is probably the greenest way to go long term. An electric water heater is wasting energy by keeping that water hot, so tankless electric might also save energy there, or it might be a wash.

Edit: it would also be cool to be able to have digital temperature controls on your shower/faucet.
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GreendaleCC
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Re: Tankless Water Heater - Struggling to Justify

Post by GreendaleCC »

wilked wrote: Mon Mar 29, 2021 3:17 pmI had a plumber come by that I like, he was strongly advocating tankless. $3200 installed (Rennai), with $700 rebate from the state. ($2500 effective).
We bought a 199,000 BTU Tagaki high-efficiency, 10 GPM tankless heater from Amazon two years ago for <$1,100. Can't quote the installation cost, since it was part of a larger remodel. It's worked well.
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Re: Tankless Water Heater - Struggling to Justify

Post by Soon2BXProgrammer »

GreendaleCC wrote: Mon Mar 29, 2021 9:20 pm
wilked wrote: Mon Mar 29, 2021 3:17 pmI had a plumber come by that I like, he was strongly advocating tankless. $3200 installed (Rennai), with $700 rebate from the state. ($2500 effective).
We bought a 199,000 BTU Tagaki high-efficiency, 10 GPM tankless heater from Amazon two years ago for <$1,100. Can't quote the installation cost, since it was part of a larger remodel. It's worked well.
I agree with Takagi.. I have the 190k (no condensate line) equivalent. its a great unit, They are programable to a higher temperature, because they support boiler type uses. They are built to last.

They are not HomeDepot/Lowes quality units, and are not that much more expensive.

I forgot the biggest benefit to share.. endless hot water for a hose to wash the car... or hooked up to your pressurewasher.... (note if hooking to your pressure washer, see what it is rated for... or be ready to buy a new one... )
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Re: Tankless Water Heater - Struggling to Justify

Post by abuss368 »

UGI advised against. Said replacement parts are a major issue.

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Re: Tankless Water Heater - Struggling to Justify

Post by ElJefeDelQueso »

wilked wrote: Mon Mar 29, 2021 3:17 pm We are adding a new master bath, increasing total baths to 3. The new bathroom will have a shower and a soaking tub, ann the tub itself will be ~ 50 gallons.

I currently have a 40 gal gas-fired Bradford White water heater. ~8 years old, no issues with it, anode replaced 2 years ago (was 60% spent).

My original plan was to add a second 40 gal water heater and pipe them in parallel, thus becoming an effective 80 gal tank. A new unit is about $650 and install might be $500-1000.

I had a plumber come by that I like, he was strongly advocating tankless. $3200 installed (Rennai), with $700 rebate from the state. ($2500 effective).

My basement is unfinished, I have plenty of floor space, and I also have a Moen Flo which will shut the water supply off on a detected leak.

My understanding of the tankless, and my thoughts on it:
*Unlimited hot water! - Why would I want this? I don't want unlimited, I only want 'enough'. With our current 40 gal heater unless we take back-back-back showers we don't run out. I think it's happened twice. With 80 gal I think it'd be extremely difficult to run out.
*More efficient energy-wise - Our gas bill is very low in the summer (when we're not using it for heat), maybe it's $25/month? I could maybe see $100/yr savings here, which is not enough to account for the additional upfront cost.
*Takes up less room - Not important to me with a big unfinished basement
*Requires annual flushes and 5 year full maintenance - Not too big a deal, but is more than I do with the tanks
*Will be slower to get hot water, maybe 40 seconds - This might be frustrating. I know you can add things like circulation loops / etc but that is more complexity and money.

---------
I want to talk myself into it to be honest, but it seems like a loser on paper. Am I missing it? Is the selling point of 'unlimited hot water' really that exciting?
We had no choice - came with the house. But I really like it and would pay to install. It is handy because we travel alot, and I never hear complaints about hot water running out when we are home.
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Re: Tankless Water Heater - Struggling to Justify

Post by illumination »

Plumbers might advocate tankless because it's more of a markup for them, on both their labor and the product itself. Also, many times they get regular maintenance service from customers for descaling, you can go on YouTube and see what's involved. Sometimes it also it requires a larger gas line to the unit than what a traditional tank requires, that's more labor charges a plumber can ring up. Reinstalling a traditional water pump is a 1 hour job and the plumber probably won't see you again for 10 years. I had an elderly relative that somehow spent around $12,000 for a tankless system because a plumber convinced him to convert and reconfigure his home's system with a tank on the opposite side of his home. A $200 recirculator pump would have accomplished the same thing.

I see no monetary advantage to tankless, the entire package is easily $1,000+ more than a traditional tank, probably around $6 a month in gas savings (and that's me being generous, I have gas bills as low as $20 a month total) I don't run out of hot water with a 50 gallon tank.

I can understand tankless for people where space is a premium or need the feature of "never" running out of hot water.
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Re: Tankless Water Heater - Struggling to Justify

Post by marti038 »

Lots of good comments here. After evaluating tankless vs. heat pump water heater we went with the 80 gallon heat pump water heater and have been happy. Here are a few plusses that might matter to you.

1) It's energy efficient. You mentioned a tax rebate/break. Not sure if a heat pump qualifies, but it's cheap to own.
2) It gives us 80 gallons of stored hot water when the power goes out. We rarely lose power though and when we do we've still never run out of hot water.
3) The tankless was going to require intake and exhaust air piping through the basement wall, an upgraded gas line and meter (this may not apply to you) in addition to the rerouting of hot, cold, and condensate water and the electrical connection.
4) Our water heater is in a sealed crawl space/basement, so we couldn't have any exhaust venting into the space. The heat pump also blows cool, dry air into the space which aids in keeping it nice and dry.
5) If, God forbid, the tank failed and we had water running unabated into the basement we are fortunate enough to have a drain down there so it would have a place to go.
6) It was much easier to install than a tankless.

I'd say the biggest drawbacks to the HP water heater are 1) it required a 30amp power connection and 2) the 80 gallon tank takes up quite a bit of space.
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Re: Tankless Water Heater - Struggling to Justify

Post by Waywayafar »

We've had a Tagkagi for eleven years now. Zero issues so far. The programming on the tank has been flawless and I can only imagine how much better the programming is eleven years later. I clean the interior coils/plumbing with a CLR/water solution once a year.

It's nice to not have to worry about having hot water. We can have multiple showers going or one after another with zero concern of having enough hot water.

It does require a larger gas line and stainless steel exhaust piping. Does it pay for itself? Probably not, but there are more upside factors involved in the equation, even on a financial forum.
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Re: Tankless Water Heater - Struggling to Justify

Post by alfaspider »

JonnyDVM wrote: Mon Mar 29, 2021 8:08 pm Tankless is ok. We had two 50 gallons in tandem with a recirculater which we replaced with a tankless a couple years back. The water was getting quite brown and they needed to be replaced but I liked them because the water was magically instantly hot. The tankless takes a few seconds. The biggest advantages to a tankless system as already mentioned are it won’t ruin your basement if it fails and the space savings. All the plumbers swear by them. Maybe that’s because tankless are more profitable for them to install, but I genuinely think it’s because they are the superior system. I’ve known people who’s basement was ruined by a faulty hot water tank. It’s not that uncommon.
It's even worse in places that don't have basements. Around here, water heaters are often in the attic and can ruin the room below.
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Re: Tankless Water Heater - Struggling to Justify

Post by BradJ »

neilpilot wrote: Mon Mar 29, 2021 3:30 pm Unless you spend extra for a battery backup, the tankless heater's controls will not function if your electricity goes out. The basic Bradford While gas heater doesn't use an electrical power source.
This is the sole reason why I would not want a tankless. Thank you for posting this overlooked con of having a tankless water heater.
rascott
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Re: Tankless Water Heater - Struggling to Justify

Post by rascott »

I had one. Removed it and replaced with a tank when it last time started leaking. Gave me too many problems, impossible to find someone that actually knew how to fix.

No savings to be had due to the cost. A tank is an easy replacement when they go out. Enough said.
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Squirrel208
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Re: Tankless Water Heater - Struggling to Justify

Post by Squirrel208 »

wilked wrote: Mon Mar 29, 2021 3:17 pm *Requires annual flushes and 5 year full maintenance - Not too big a deal, but is more than I do with the tanks
FWIW tank-style water heaters require annual flushing too. Many plumbing pros recommend even shorter intervals, such as every 6 months. Sediment buildup is more likely to occur in a tank due to the increased volume and duration of water sitting in the tank.
squirm
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Re: Tankless Water Heater - Struggling to Justify

Post by squirm »

We used to run out of hot water after a long shower, I just cranked up the heat all the way on the water heater no more running out of hot water. It's still going strong so can't justify a tankless yet.
RobLyons
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Re: Tankless Water Heater - Struggling to Justify

Post by RobLyons »

I vote not worth it. And when conventional water heaters fail, they almost always show other signs of failure before ever *flooding* the basement.
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ncbill
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Re: Tankless Water Heater - Struggling to Justify

Post by ncbill »

OP should just go with another 40 gallon paralleled with the existing 40 gallon.

That's what mom did at her last house...and no, it didn't require an upgrade to the gas line.
Gadget
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Re: Tankless Water Heater - Struggling to Justify

Post by Gadget »

Squirrel208 wrote: Tue Mar 30, 2021 11:57 am
wilked wrote: Mon Mar 29, 2021 3:17 pm *Requires annual flushes and 5 year full maintenance - Not too big a deal, but is more than I do with the tanks
FWIW tank-style water heaters require annual flushing too. Many plumbing pros recommend even shorter intervals, such as every 6 months. Sediment buildup is more likely to occur in a tank due to the increased volume and duration of water sitting in the tank.
I'm apparently just ignorant. I had no idea a tankless required annual and/or 5 year full maintenance. We've had ours since 2009 and I haven't touched it.

What are you supposed to flush in a tankless? This makes more sense to me on a tank system where you could get buildup at the bottom of the tank.
tm3
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Re: Tankless Water Heater - Struggling to Justify

Post by tm3 »

IMO the main reason to buy tankless is to avoid the catastrophic failure and flooding of a tank. I've had it happen to 2 friends of mine.

The energy savings is negligible. I added it up based on my actual use. Others may feel differently.

One thing to consider re tankless is that annual descaling is recommended. It could probably be a DIY project but it is more complex than I would like to tackle. The local plumber here charges $150 -- that $150/year easily eclipses any potential savings tankless may provide.
neilpilot
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Re: Tankless Water Heater - Struggling to Justify

Post by neilpilot »

alfaspider wrote: Tue Mar 30, 2021 11:02 am

It's even worse in places that don't have basements. Around here, water heaters are often in the attic and can ruin the room below.

A water tank leak almost always start off very small. It's typically in a catch basin that drains to the outside and will prevent any interior damage. At least that's my experience after each of my 2 50gal tanks in the attic failed a few years back. In fact, in one case the water dribbling out the drain on the side of the house was my first indication that the tank had failed.

Of course, in our area the tankless often also goes in the attic. It can also leak and ruin the room below, and is frequently NOT in a similar catch basin.
alfaspider
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Re: Tankless Water Heater - Struggling to Justify

Post by alfaspider »

neilpilot wrote: Tue Mar 30, 2021 1:05 pm
alfaspider wrote: Tue Mar 30, 2021 11:02 am

It's even worse in places that don't have basements. Around here, water heaters are often in the attic and can ruin the room below.

A water tank leak almost always start off very small. It's typically in a catch basin that drains to the outside and will prevent any interior damage. At least that's my experience after each of my 2 50gal tanks in the attic failed a few years back. In fact, in one case the water dribbling out the drain on the side of the house was my first indication that the tank had failed.

Of course, in our area the tankless often also goes in the attic. It can also leak and ruin the room below, and is frequently NOT in a similar catch basin.
Some quick and dirty contractors will install them without a drain. My house came with a hot water heater with no drain and nowhere to run a drain to (it's in a closet in the stairwell with nowhere to run a line outside). Other than replacing the thing, my only option is to have a leak monitor and hope it doesn't go out while we are away.

You are correct that a tankless could leak, but so could any plumbing fixture. Normal plumbing fixtures don't have the same corrosion issues as a hot water tank.
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wilked
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Re: Tankless Water Heater - Struggling to Justify

Post by wilked »

Gadget wrote: Tue Mar 30, 2021 12:28 pm
Squirrel208 wrote: Tue Mar 30, 2021 11:57 am
wilked wrote: Mon Mar 29, 2021 3:17 pm *Requires annual flushes and 5 year full maintenance - Not too big a deal, but is more than I do with the tanks
FWIW tank-style water heaters require annual flushing too. Many plumbing pros recommend even shorter intervals, such as every 6 months. Sediment buildup is more likely to occur in a tank due to the increased volume and duration of water sitting in the tank.
I'm apparently just ignorant. I had no idea a tankless required annual and/or 5 year full maintenance. We've had ours since 2009 and I haven't touched it.

What are you supposed to flush in a tankless? This makes more sense to me on a tank system where you could get buildup at the bottom of the tank.
Mainly descaling / removing buildup on the tubes. As noted above CLE does it nicely. I’ve heard there are potentially service ports for it? I think the 5 year probably replaces the gas-fired elements or something like this
illumination
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Re: Tankless Water Heater - Struggling to Justify

Post by illumination »

Squirrel208 wrote: Tue Mar 30, 2021 11:57 am
wilked wrote: Mon Mar 29, 2021 3:17 pm *Requires annual flushes and 5 year full maintenance - Not too big a deal, but is more than I do with the tanks
FWIW tank-style water heaters require annual flushing too. Many plumbing pros recommend even shorter intervals, such as every 6 months. Sediment buildup is more likely to occur in a tank due to the increased volume and duration of water sitting in the tank.
But it's way easier to flush a conventional tank water heater, about as complicated as attaching a garden hose. Also, almost nobody actually does it regularly and tanks last a long time.

Here's a plumber doing a tankless descaling, how many homeowners do you really think do this themselves? You can see why plumbers would love this.

https://www.youtube.com/watch?v=dJ3DYLDEkz0&t=286s
dachshunddad
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Re: Tankless Water Heater - Struggling to Justify

Post by dachshunddad »

I had the tankless /tank dilemma also. I have gas and the break even for tankless was 20 years. I just swapped the tank out. I could change the tank out more than 2x and still be ahead. If you don’t have to retrofit (ie new build) it makes sense. Or if you go from electric to gas it has bigger savings.
bago
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Re: Tankless Water Heater - Struggling to Justify

Post by bago »

For what it's worth when our hot water heater reached the end of its life a few years ago, we switched to tankless. We have a single Noritz tankless water heater powered by natural gas in the basement of our 3-story house. It works great and I'd get tankless again. For showers on the top level of our home, it does take about 45 seconds for the hot water to get going, but that's not a big deal to us. I like that it is more energy-efficient and reduces the risk of water damage in our finished basement. If you go this route, you will want someone to help you choose the correct size based on your anticipated usage (neither too small nor too large).
Dicast
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Re: Tankless Water Heater - Struggling to Justify

Post by Dicast »

We have a Navien. It keeps a little hot water internally circulating so it really doesn’t take any longer than our old tank did. With several children we can run bath for everyone and never have a problem. Definitely didn’t do it for cost savings but replacing an 80 gallon tank is not cheap either.
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Re: Tankless Water Heater - Struggling to Justify

Post by Valuethinker »

quantAndHold wrote: Mon Mar 29, 2021 4:03 pm We looked into tankless, and couldn’t justify the cost. It was expensive, and the payback period was going to be longer than the expected life of the heater.

At the time we were researching, the local utility was pushing people to go with solar hot water systems. They were even more expensive to buy, but then your hot water bill would go to zero. Basically, you have a more or less normal hot water tank, which is heated by panels on the roof with some sort of recirculating pump. As an empty nest couple, we didn’t use enough hot water for that to be cost effective either, but for a family with kids, it seemed like a reasonable deal.

So we still have a normal 40 gallon tank.
Unless you live in one of America's desert climate zones, I doubt a solar HW heater would have freed one from HW heating bills.

The problem is seasonality. Most places in USA you have more than too much solar insolation in July-August. Whereas in the Dec, Jan, Feb period, it would not produce enoug HW.

The solution would be a much larger tank. I have heard of 1000l (say 200 gal) tanks (in homes specifically built on an environmental credo). Or a large area full of crushed rock & insulated).

Electricity is intrinsically a more valuable form of energy (albeit not so easily storable) so generally, if people have a choice, I suggest using their scarce roof space for Solar PV. Recognizing that because of rising solar penetration, there are times of day when wholesale electricity prices are going negative (California's "duck curve: where very low electricity prices around mid day shoot up very sharply around 4 pm).
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