Info and Advice on Tankless Water Heaters

[JoyfulNoise]

Hey y'all ... title says it.

This morning I awoke to a flood in my walk in closet. The closet room shares a common wall with an outside utility closet where the original builder of these homes STUFFED the HVAC furncae/air-handler and one of the 50-gallon tank gas water heaters (my house has split systems, one set is in the utility closet, the other set is in the garage). Anyway, the flood in the closet was caused by the water heater leaking. Tank has a hole somewhere in it. Spent the better part of the day drying out the AC air plenum which sits below the base of the air handler where the equipment is installed (goofiest way of doing an AC system I have ever seen ... literally HATE it but it's what I have). So all flooding is fixed and walls are being dried out (I'll get to any drywall repair later ... no one sees the walk in except me and the little lady so I have no one to impress ....).

Anyway my options are to install a new 50 gallon tank water heater or consider going with tankless. My initial thoughts are this -

1. It's gotta be gas because that's what I have.
2. It needs to be compact because space is limited.
3. Its in an outdoor utility closet so "out of sight, out of mind, never gets looked at regularly" is the guiding principal - therefore I need something that is ROCK-SOLID in terms of longevity and operations. I am willing to sacrifice bells and whistles if the unit will have very low downtime. I don't need fancy, I need reliable.

I'm intrigued by tankless but the array of options and manufacturers is endless. I'm looking for comments from folks that have them and can speak to their performance and reliability. I'm ok with a little bit more maintenance than the traditional tank heater (drain every 6 months or so and change a Mg anode every couple of years is about all they ever need) as long as the unit will go the distance.

All thoughts, opinions, and recommendations are welcome.

Thanks in advance!

 

[mknauss]

We have a noritz. 7 years and zero issue or maintenance. No bells or whistles. Model NR 981-SV.

 

[YippeeSkippy]

When our 50 gal gas tank bites the dust we are going with a tankless system if just to free up the space that ginormous tank takes. My brother says they never run out of hot water with their tankless.

Maddie

 

[YippeeSkippy]

 

[HermanTX]

My son-in-law replaced 2 40 gal tanks with a Navian 240-A2 a year ago. It has a 15 year heat exchanger warranty and 5 yrs parts warranty. It has dual stainless steel heat exchangers delivering an Ef rating of 0.96 and upto 11.2gpm. It has a Grundfos built in recirculating system for optimal hot water delivery. He has NG line.

He is very pleased with it and I am looking at same system for my home although I have larger tanks

 

[Rancho Cost-a-Lotta]

We have a Takagi model TH-3-DV (NG) unit which was installed with the home build in 2004. Zero issues. I use a Heater Treater prefilter to reduce mineral deposits. With a softener, you probably don't need it. The system can flushed with a water/vinegar solution using a sub pump in a bucket to remove scale.

I do miss having a hot water circulation pump. They're not compatible with tankless systems.

 

[ajw22]

Tank or tankless you should have water sensors connected to alarms under every water tank in the house including toilets. They have saved me from damage a few times. It is not if you will have a water leak, it is when. And water can cause more damage to a house then a fire.

Hot water tanks seem to last 10 to 15 years before they doing a leak. In my 25 year old house I am on the third set of hot water tanks.

 

[JoyfulNoise]

Tank or tankless you should have water sensors connected to alarms under every water tank in the house including toilets. They have saved me from damage a few times. It is not if you will have a water leak, it is when. And water can cause more damage to a house then a fire.

Hot water tanks seem to last 10 to 15 years before they doing a leak. In my 25 year old house I am on the third set of hot water tanks.

These water tanks are original to the home construction so 2005/06. And you can be assured that the cheap home builder probably got all these heaters for the homes in my association at some discount fire sale for old products that are obsolete. So they lived and functioned for 17 years. I suppose that’s a good run.

Still got one in the garage so, depending on what my plumber comes back with on a quote, I might bite the bullet and replace both of them at the same time.

As for alarms, any good recommendations there? Again, I’m a simple guy so I don’t need fancy. The utility closet is only accessible from outside so even though it shares a wall with the master bedroom closet, it could go unheard unless it’s a real screamer. I’m not a huge fan of WiFi IOT junk so I’d rather keep it as low tech as possible.

 

[ajw22]

I have two gas hot water heaters and when one begins leaking I replace both. I can negotiate a bit less cost for doing two at one time.

The tanks leak begin with a drip so the alarm let’s me catch it before it is a flood. Even though a fitting popped off of a drain pipe one time and the alarm got me down there before there was a big flood.

I have a Honeywell alarm system in my house and it has wireless water sensors. So a water alarm sounds sirens in the house, notifies the app on my phone, and notifies a central alarm station.

Before I put the Honeywell system in I had battery operated IOT water sensors that WiFi connected and sent emails when the sensor was triggered.

I have not needed to survey the water alarm market in a while.

 

[Mdragger88]

I don’t have a specific recommendation but just wanted to throw in a reminder to check with your utility company about rebates - that may help you narrow down a particular model/brand. Ours only has rebates on certain ones but they are lucrative.
I soooo wanna go tankless but I have an all electric house & need to upgrade my service & panel 1st. The electric tankless ones have quite the draw when they are operating - it’s not a simple swap like with gas. My water heater is original to my house from 1973! My husband refuses to replace it because he says new ones are garbage & don’t last 5 years. He’s right but I also feel like i have a ticking time bomb in my attic
Luckily someone is almost always home & when we go out of town we turn off the water & the breaker. I also have a wifi leak sensor up there. I put those things all over the place after my toilet tank cracked & flooded my bathroom.
Hoping my “classic” lasts until I upgrade the service, which should be soon barring other calamities

 

[JoyfulNoise]

I don’t have a specific recommendation but just wanted to throw in a reminder to check with your utility company about rebates - that may help you narrow down a particular model/brand. Ours only has rebates on certain ones but they are lucrative.
I soooo wanna go tankless but I have an all electric house & need to upgrade my service & panel 1st. The electric tankless ones have quite the draw when they are operating - it’s not a simple swap like with gas. My water heater is original to my house from 1973! My husband refuses to replace it because he says new ones are garbage & don’t last 5 years. He’s right but I also feel like i have a ticking time bomb in my attic
Luckily someone is almost always home & when we go out of town we turn off the water & the breaker. I also have a wifi leak sensor up there. I put those things all over the place after my toilet tank cracked & flooded my bathroom.
Hoping my “classic” lasts until I upgrade the service, which should be soon barring other calamities

A 50 year old heater that’s insane!! You’ve won the water heater lottery … TWICE!!! There’s a reason why the term “built like a brick house” was invented and your heater is it!!

Good point on the rebate idea!! I will snoop around the utility websites and see what’s offered. Maybe there’s a Federal tax credit for going tankless ?? If they give credits to all those hippies sticking solar panels on their roofs, then I want some for a water heater upgrade!!

 

[jark87]

My water heater is original to my house from 1973!

That has to be a record! We replaced our original hot water heaters a few years after we built our home 25 years ago, so our current ones are probably close to 20 years old now. Luckily, they’re in the garage so I look at the drip pan almost every day knowing that they won’t last forever, but then again, based on the longevity of yours, who knows? I looked at tankless way back when I had the original 2 replaced, but there was some issue that I can’t remember that caused me to stick with the tried and true. I’ll definitely look at tankless once I have to replace the ones we have now.

 

[Ahultin]

We installed a noritz n-084 tankless when we built our home in 2005/2006. It is still going strong though it did have to have the heat exchanger replaced under warranty about 11yrs in. This was most likely due to an improper vent Installation when new causing acidic condensate to drip on the heat exchanger as it runs. When this does finally die I will not hesitate to install another. I have installed several of these for friends and family and the only real problem anyone complains about is that since they never run out of hot water, kids never get out of the shower.
I installed one at my daughters college home in Ohio even though everyone local said it wouldnt work due to their cold winters and it did not skip a beat even with 6 girls living in the house.

Maintenance wise, I flush the heat exchanger for an hour with 4 gallons of vinegar 2x per year using a simple submersible pump and stainless washing machine lines.

 

[Flying Tivo]

Went with Rinnai America Corporation. They are on the expensive side, but no issues whatsoever. That is also why i bought the water softener. I did the vinegar wash every year. They have propane and NG. I have 3 of them since i section the house so the hot water was almost on demand to save on water on every spot. Literally it takes 5 seconds of running water to get hot water in the shower.

 

[DrewLG]

We have a noritz. 7 years and zero issue or maintenance. No bells or whistles. Model NR 981-SV.

Noritz here, too. N-0751M, which is the older model of what you have (200000BTU, 9.8GPM, etc.). Ours was installed in 2008 and needed its first repair earlier this year -- I replaced the igniter, around $50 and about an hour to diagnose and R&R. I expect it to last at least another decade.

As for alarms, any good recommendations there? Again, I’m a simple guy so I don’t need fancy. The utility closet is only accessible from outside so even though it shares a wall with the master bedroom closet, it could go unheard unless it’s a real screamer. I’m not a huge fan of WiFi IOT junk so I’d rather keep it as low tech as possible.

It's hard to get lower tech than this. I have one behind every toilet, under every sink, and in the tray around the clothes washer:


https://www.amazon.com/Glentronics-Inc-BWD-HWA-00895001498-Basement/dp/B000JOK11K

A tip, if you decide to buy these: Fold a section of paper towel over the sensor, so even a slow drip will soak the paper towel and close the contacts. Otherwise they won't close until they're in at least 1/32" of standing water.

 

[Killer95Stang]

I'm at the 9 year mark on my Rheem Super Condensing tankless water heater. So far it has been one of best investments I've done over the years. I did a DIY install, but it did require a bit of work, like upsizing the gas line, adding a water softner at the same time and adding new electrical outlets to the closet where it is located. The plus side of the condensing unit is the cool exhaust temps, allowing you to use PVC piping for the intake and exhaust.

 

[duraleigh]

I have no constructive input but it is an interesting subject. I didn't see any comparison of electrical consumption. I was under a vague impression that tankless require more energy. No? Yes?

 

[Bperry]

Does the current leaking tank not have a drain pan under it? I assumed anything inside the house needed to have a drain system to safely handle leaks like that, but looks like I was wrong.

 

[wireform]

As far as thankless heaters I had one for 10+ years until I went with high efficiency boiler system for the whole house so at the time I switched to indirect hot water. One tip many don't know about is to install a mixing valve right at the output to the hot water tank so there's no way to deplete the tank of its hot water fast as it pre mixes the hot and cold and delivers water to the house faucets and showers a little hotter then one can tolerate thereby keeping more in the tank for reserve. This way you can size the tank slightly smaller then what's recommended.
As far as water sensors goes I had the WATCHDOG WATER ALARM mentioned earlier and it worked well. Now I have several These and they're small and more compact. Can't remember if the battery can be changed but ours still works ( I test on occasion) and is several years old.

 

[JoyfulNoise]

Does the current leaking tank not have a drain pan under it? I assumed anything inside the house needed to have a drain system to safely handle leaks like that, but looks like I was wrong.

No drain pans. I don’t see how you could even fit one in if you wanted to as the utility closet is barely large enough to hold the equipment in it. Also, we technically live out in the county, not the main city of Tucson, so the building codes out here are lax and I doubt there’s any requirement to have them. Even so, inspectors are easily paid off to look the other way on just about anything.

About half the houses I. The subdivision are like mine where half the utilities are separated into an external closet and the other half of the homes have all their utilities in the garage. With a split floor plan (master suite separated from the families’ bedrooms), they probably want to avoid long hot water and AC duct runs, so half the utilities are split off to be closer to the points of use.

The real tragedy in all this is that my kitchen hot water line fed from the heater that died and so there is no hot water in the kitchen … which means no dishwasher!! So now everything we use has to be washed by hand I told the kids that it’s paper plates and plastic utensils until the situation is resolved