Literally just had a conversation Friday with my neighbor about his tankless heater and he loves it. My wife is always complaining about losing hot water when she showers. Low and behold the water heater is leaking this morning and has a pan full of water. I have heard the reliability on a tankless is garbage but that was 6-7 years ago when I talked to a plumber. Pros and cons for each one?

I love mine and it is 12 years old. No issues. Hot water for as long as I want. It does take time to get hot on the furthest bathroom.

Gas or electric? I had my gas heater switched out last year for Navien. The model I had installed did not require a larger gas intake and can exhaust via PVC. So far, no issues. If you size correctly, you can run multiple things at once with no issue. It does create some condensation as a by product you will have to account for that and yearly service, which you can do yourself.

Tankless

EOT

Barnacle brings up a good point on cost. If going with certain models, gas supply can add dollars as well could proper venting. Heck, you may even need a larger meter which there are ways to get that for free from the gas company.

Outside of that, I miss our tankless from old house vs new house, but two 50 gallon tanks do the trick.

Currently we have a gas 40 gallon just for the master suite. It runs out of water after a 15 min shower. I would be looking for a tankless gas heater.

coolerguy12 said:

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Currently we have a gas 40 gallon just for the master suite. It runs out of water after a 15 min shower. I would be looking for a tankless gas heater.

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How old is the existing heater ?

Something sounds off. You either have sediment In the tank, temp set under 125 or take showers on all hot at 125 degrees.

What kind of shower head ?

All of the newer ones are 2.5 GPM or less. 2.5 has been mandated since the early 1990's.

If you aren't wanting to pay to upgrade to tankless my suggestion is a $500 50 gallon tank and if that isn't enough then get a tank booster to double your hot water amount


https://www.homedepot.com/p/Heatguard-Water-Heater-Tank-Booster-24409/203721329


Tankless is nice but it's not perfect either

For starters the control boards are susceptible to lightning strike and power surges

Also you have to have a 110 power source to plug the tankless into

So if your power goes out you no longer have hot water versus a tank gas heater

You're upfront cost is going to be quite a bit more on the installation as well depending on if you need electrical and gas line upgrading.

It's 11 years old. I have seen some stuff where GE warranties heaters for 12 years. We have two shower heads in the shower and rather than just using one when it's just her in there she likes to use them both. (I do it too but I shower much quicker). She might get 20 min before it starts to cool off.

Is a 50 gallon the same height as a 40 gallon? The water lines are hard piped about 8" above the 40 gallon so I don't have a ton of room to work with.

How tall is the existing heater ?

How much space is between the bottom of the pan to where the water lines come out ?

A rheem 50 gallon tall gas will be ~ 59 inches tall and 21 inches wide

They make a medium too, I think it is around 48-49 tall and 23 wide


Also does the T&P valve piping drop to the pan ? Or does it terminate to a pipe in the wall ? There is a possibility your valve could be what is leaking and not the tank but at 12 years that's is pretty old with today's heater lifespans.

coolerguy12 said:

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Literally just had a conversation Friday with my neighbor about his tankless heater and he loves it. My wife is always complaining about losing hot water when she showers. Low and behold the water heater is leaking this morning and has a pan full of water. I have heard the reliability on a tankless is garbage but that was 6-7 years ago when I talked to a plumber. Pros and cons for each one?

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I work in the sales side of the business. Gas tankless heaters these days are extremely efficient and reliable. Electric are exactly the opposite...if you have the chance to go with a gas tankless do it. If you only have electric stick with a tank type

How do I size the gas line for it? Current unit is 40,000 BTUs, some of the tankless are 120,000. If I don't have to upgrade the gas line I'm not opposed to it. What are the good brands out there?

We had a Rheem at the old house and it's pretty standard.

I would defer to plumber on proper size of line. Meter may also come into play. If meter needs to be upsized, not uncommon, call gas company and tell them something's not right, you cannot get burners to stay on at low temperature and sometimes smell gas. They will be out shortly. When they arrive, tell them you have been thinking of a tankless and is your meter sufficient. Likely, if they determine it is not sufficient, they will swap out at not cost,

If the Mrs. is burning through your tank heater with her 20 minute plus shower, you are not solving for energy efficiency. You will never see a dime of savings. But, you may end up with a wife who enjoys long steaming hot showers that could last until 2nd degree burns set in. Choose wisely.

I did a lot of research and went with Navien, and have been happy with it.

Look online for gas line service flows.

Look at Tables

Essentially you can look at the length from the meter to your water heater. Figure out the cubic feet per minute/hour and then what line size you need.

For 120k BTU, you have 109 cubic feet per hour. Look at page 4 of my link. That gives you a total of 90 feet from the meter to your unit with a 3/4" line. If you have a 1" line, you can go almost 300 feet before you run out of "oomph" to get the gas to the unit.

Also, keep in mind the unit will pull the maximum heat rate based upon the design conditions (coldest water going to hottest water). If you live where the water is mostly warm on "cold" days and/or you only output 110 F, your duty will be less.



Another thought to keep in mind is when you heat water, you form solids if your water is hard. In my old house, we had a tankless; loved the system. But it would clog the aerators/filters at the faucets depending on the use (kitchen and master shower about once every three weeks). I had to install a whole house hot water filter (got on Amazon, installed myself and I think I made a thread about it here) to keep the trash from clogging things. Normally, your tank water heater catches all the solids that form (essentially rocks). Your tankless has no where for it to go except out.

The hot water filter was good. I didn't have to actually 'change' the filter, just open it up and dump the rocks out and wash off the filter. Did this about once every 6 months.

~egon

I've had a couple of gas tankless water heaters, and they are the only way to go. I recommend spending a bit more for a high-efficiency condensing unit. It allows you to vent it with cheap PVC instead of double walled stainless with large clearance. A great place to install is above a garage or laundry room sink, which takes care of the condensate and makes maintenance a breeze.

In addition to isolation valves, I recommend throwing this into your setup to extend the life of the heater. 3M Aqua-Pure Whole House Scale Inhibition Inline Water System AP430SS, Helps Prevent Scale Build Up On Hot Water Heaters and Boilers https://www.amazon.com/dp/B000NKETXQ/ref=cm_sw_r_cp_api_i_6rtxEb80RBGR8

coolerguy12 said:

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I have heard the reliability on a tankless is garbage but that was 6-7 years ago when I talked to a plumber.

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That sounds like plumber for "I don't like installing them"... There are good and bad brands out there, but they've been the standard in other parts of the world for a long long time.

It's a good idea to stay on top of the descaling (depending on how the water is in your area) but they can last a long time. I think they're expected to last a few years longer than a regular water heater.

coolerguy12 said:

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Currently we have a gas 40 gallon just for the master suite. It runs out of water after a 15 min shower. I would be looking for a tankless gas heater.

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That's 2.5gpm, which means she's either taking a scalding hot shower, or your water temp is way too low.

Make sure to check permit requirements. Trust me on this. You may go to sell your house and discover the plumber skipped that step.

We are building a new house and I'm trying to decide on tankless vs two 50 gallon tanks. Our current house has two 50 gallon tanks and we could shower for hours without losing hot water. So I personally don't see any additional benefit of unlimited hot water. My understanding is that tankless actually limits you on the number of hot water sources you can use at once (dishwasher/washing machine/shower wouldnt all heat properly if used at same time). Our current gas bill is $45 last month, so how much are we really going to save on monthly gas bills? Consumer reports has a good article that says around 25 years for payback. In conclusion, I'm thinking of saving the $2,500 of cost to have tankless and spend the money on something that we'll actually see a benefit of. The ONLY benefit I personally see of tankless is the smaller size. So many disadvantages of tankless, from the required maintenance, to I think inability to get hot water if power is out? I'm just not getting the "no brainer" that everyone acts towards tankless. Consumer reports actually rates gas tanks higher than tankless, which should tell you something.

We did the same thing with the filter.

JP76 said:

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For starters the control boards are susceptible to lightning strike and power surges

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This applies to 95% of appliances made in the last 10 years... I'm sure it happens, but I don't think this is happening enough to let it sway this kind of decision.

I don't see how 2 50 gallon tanks are significantly less than a tankless. A 50 gal tank is around $640 (so 2 for $1280). A tankless is about $1300. Add the labor in and you are installing 1 heater versus 2.

As for water flow, the unit below is 9.5 GPM. A faucet is 1.5 and a shower is 2.5, so you get the idea.

Also, where do those 2 50 gal tanks go...the attic? The tankless can go outside which makes way more sense to me.

Maintenance. they both have maintenance. For a tank, you have to drain yearly (no one does though). For a tankless, there is a yearly process.

Finally, heating water when you need it saves energy versus heating it and storing it.

Links for reference:
https://www.homedepot.com/p/Rheem-Performance-Platinum-9-5-GPM-Natural-Gas-High-Efficiency-Indoor-Tankless-Water-Heater-ECOH200DVLN-2/304820618
https://www.homedepot.com/p/Rheem-Performance-Platinum-50-Gal-Tall-12-Year-40-000-BTU-Natural-Gas-Tank-Water-Heater-XG50T12HE40U0/204697785

Of course it does. That would be true on a conventional as well unless you have recirculating pump.

Sweet Kitten Feet said:

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Of course it does. That would be true on a conventional as well unless you have recirculating pump.

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It does take a little bit longer with a tankless because there isn't hot water ready to go into the pipes as soon as there is flow, but its really not that bad.

If I build a house, I'm going to put a tankless outside and a recirculation loop.

Get a Navien and forget about it. Had one for 5 years on propane and there is not one complaint.

brznby said:

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Get a Navien and forget about it. Had one for 5 years on propane and there is not one complaint.

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What bothers me about Navien is that finding owner reviews or feedback is damn near impossible. Google "navien water heater reviews" and see if you can find any reputable or decent set of reviews from owners.

Then do the same with Rheem, Rinnai, Takagi, etc.

Naviens appear to be favorites of licensed plumbers and available through supply warehouses.

We used these guys for our tankless 2 years ago. Very happy with everything.

In Houston
Www.ho****erguys.com

TMoney2007 said:

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coolerguy12 said:

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I have heard the reliability on a tankless is garbage but that was 6-7 years ago when I talked to a plumber.

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That sounds like plumber for "I don't like installing them"... .

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Well who can blame them, it is a tankless job.