Tankless Water heater

[Music Lover]

With the programmable app, the tankless for us is less expensive. I don’t understand the comments about them being complicated. I am not the most mechanically inclined individual on the planet and I find them easy. Easier than when I had to drain a tank in my basement.

Less complicated because I can install a regular HW tank myself in less than a half hour. The tank costs much less plus there's no installation cost, easily surpassing any saving that a tankless might have.

To drain a tank you just open the tap at the bottom, that's not complicated either. At least, it shouldn't be.

 

[skyking1]

"In a basement"
if he did not have a floor drain handy, then it is a real PITA.
The new house gets a floor sink in the equipment room. it gets an equipment room!

Condensate line from HVAC goes in, water heater pan goes in, T&P line from the water heater.

 

[ERD50]

That is the only time I have heard a story like that. Typically it is not an issue.

I was kind of surprised myself. But I looked at some numbers, and for a home around here, I think the typical situation is (in thousands of BTUs):

~80 Furnace
~30 WH Tank
~20 Stove-top/Oven
~20 Gas Dryer

So you need capacity for ~ 150 if all were on at once. The only thing I might consider really rare, would be full oven/stove on with everything else, but certainly the others could all occur at once (water heater running at the same time as dryer to wash/dry), but it needs to be planned for. And the stove-top is a smaller component of that, I think the oven itself could be ~ 16?

And a tankless is ~ 150~250? So that's about double or more (subtract the 30 for the tank WH). I don't know how much margin they put in the gas supply, but if it is 100%, you've used it all. Could that possibly 'starve' another appliance under marginal conditions?

-ERD50

 

[COcheesehead]

"In a basement"
if he did not have a floor drain handy, then it is a real PITA.
The new house gets a floor sink in the equipment room. it gets an equipment room!

Condensate line from HVAC goes in, water heater pan goes in, T&P line from the water heater.

LOL and I should have added a “nicely finished” basement.
At least out tankless is in the garage which makes it easy for descaling.

 

[Music Lover]

LOL and I should have added a “nicely finished” basement.
At least out tankless is in the garage which makes it easy for descaling.

A regular tank can go in the garage too. They don't require descaling either.

 

[ncbill]

A regular tank can go in the garage too. They don't require descaling either.

Mom had two "short" 40 gallon natural-gas-fired tank water heaters ganged together in the crawl space.

We never ran out of hot water either.

I'm sure the installation, operating, and (zero for the decade she lived at that house) maintenance cost were less than for any tankless water heater.

 

[mpeirce]

Vive la différence!

 

[Texas Proud]

Tankless is a good marriage with gas, because the gas piping can deliver a whole lot of BTU without a size change for your house.
With electric, it takes a lot of amps, so much so that many would-be customers can't go that way without upgrading the service to their home.
We are all electric and won't be doing tankless or heat pump, because the Ground Source Heat Pump (GSHP) has a desuperheater loop that will heat the water in the tank to ~120 as a byproduct of heating the home. My brother turned off the breaker to his hot water tank with his GSHP.

Not sure what is needed today but when I got mine 20 or so years ago I needed to upgrade the exhaust.. my old heater had a 3 inch exhaust.. the tankless needed a 4 inch double walled exhaust.. Also had to upgrade the natural gas line.. neither was that bad but it was not a direct replacement...


BTW, when it went on it sounded like a jet engine... lucky it was in my garage..

 

[mpeirce]

That reminds me, many of the tankless systems are “high efficiency”, condensing systems, that is, they use a condensing stage to recover almost all the waste heat going out the flue.

This means the exhaust is around 100° and can be vented out side the side of your house using a plastic pipe, not up a flue.

Ours is 95%+ efficient, while most non-condensing water heaters are 80% at best.

 

[eytonxav]

A regular tank can go in the garage too. They don't require descaling either.

My tankless is in the garage, but even a tank water heater accumulates sediment at the bottom of the tank that can make hot water fluctuate, unless periodically purged, so its not as if they are maintenance free.

 

[Telly]

Made me look.... the pipe coming into my home is ~ 1 3/8" OD, the pipe coming out of the ground into the meter is ~ 1 1/16". That smaller OD pipe is higher pressure, the meter regulates it down. I'm guessing it is also a thicker wall to stand up to being buried, so proportionately smaller ID?

Maybe they really went oversize, I don't know.
-ERD50

My sample of orange plastic gas underground service tubing is about 1 1/16" OD, and the wall thickness is just a tiny bit under 1/8" thick. IIRC, service pressure is ~70 PSI. Regulator knocks it down to a few " of WC.

 

[Iusta]

I have 2 gas powered instant water heaters, one for up stairs and one for downstairs. They are fantastic, efficient and and low running cost. Do not get electric as they are less efficient and if you live in a state where electricity is expensive like CA u will regret it. The electric tanks are good only for small apartments.

 

[Ronstar]

OP here - Got my replacement element in the mail from Rheem, set up an appointment to have their plumber install it. Next Tuesday.

I can't wait until Tuesday. So I started to do install the element myself and noticed that the element isn't leaking - the leak is coming through a seam higher up in the element compartment. Then I found a pinhole leak in the fitting connecting to the hot water out line. Water was running down the fitting into the shell of the tank then out through the seam in the element compartment.

So I drained the tank and installed a new fitting. Waiting for the cpvc cement to cure. We'll see how this turns out in a couple of hours.

 

[pb4uski]

^^^ Your couple hours are up. How did it work out?

 

[Ronstar]

^^^ Your couple hours are up. How did it work out?

Well I think I stopped the leak. No leaking fittings now. The element compartment is still wet, maybe due to previous leaked water still escaping from between the inner tank and outside shell. Very little water dripped into the pan last night - maybe half an ounce. Going to wait until 100% dry before I turn on the breaker.

Looks like another cold shower today.

 

[old medic]

Good to hear you got it fixed. On our house rebuilt, we are going with a split system. A gas Tankless in the garage feeding the washer, utility sink and the house water heater. That water heater will be a small 6 or 11 gallon RV style that runs on both gas and electric. The camper we live in has an 11 gallon one and we ran out of water 1 time in 4 years. Had company and 4th shower got cool.

 

[Ronstar]

Good to hear you got it fixed. On our house rebuilt, we are going with a split system. A gas Tankless in the garage feeding the washer, utility sink and the house water heater. That water heater will be a small 6 or 11 gallon RV style that runs on both gas and electric. The camper we live in has an 11 gallon one and we ran out of water 1 time in 4 years. Had company and 4th shower got cool.

I was thinking about a split system this morning. While waiting a few days for the warranty plumber to show up, I could pop in a small tankless water heater for my shower in an hour or so. DW showers in the master bath. I shower in the lower level bathroom next to the utility room. I could easily put in a tankless water heater 5' from the washer and my shower.

 

[skyking1]

It's been a great discussion. I am designing and building from scratch and get to choose.

 

[Happyras]

I was kind of surprised myself. But I looked at some numbers, and for a home around here, I think the typical situation is (in thousands of BTUs):

~80 Furnace
~30 WH Tank
~20 Stove-top/Oven
~20 Gas Dryer

So you need capacity for ~ 150 if all were on at once. The only thing I might consider really rare, would be full oven/stove on with everything else, but certainly the others could all occur at once (water heater running at the same time as dryer to wash/dry), but it needs to be planned for. And the stove-top is a smaller component of that, I think the oven itself could be ~ 16?

And a tankless is ~ 150~250? So that's about double or more (subtract the 30 for the tank WH). I don't know how much margin they put in the gas supply, but if it is 100%, you've used it all. Could that possibly 'starve' another appliance under marginal conditions?

-ERD50

I have to jump in on that great comment. Yes, the tankless will nearly double demand. In my case, the gas company stated that they could not upsize my meter or go to 2psi service. My gas line on my property "they claim" is only 5/8" and though at 20 psi, it would collapse with a higher flow demand and >200KBtu meter. So this was about 12 years ago and my Rinnai has been running perfectly fine. We have this 180KBtu unit, a 90K BTU furnace with HP, gas range, gas dryer, gas BBQ, gas fire pit, gas tiki torches, gas fireplace.....but like sizing an electrical panel, its all about demand. Most homes this could be a problem. Realistically, the HW demand is not very long and even with the gas fired furnace running, it seems just fine.

When I installed my tankless I made certain to keep gas lines larger to the unit. I guess the major risk might be a lean burn on the furnace if HW is called at the same time.

One more detail, OK two. After 12 years I decided to flush the tankless with vinegar, and clean the inlet. Wasted 3 gallons of vinegar, it really was not very scaled. So then I unwrapped our barn HW tank which supplies that apartment's needs, and barn sink. I was looking to replace the anode since I have not changed it since moving here in 2007. Nope, could not find it where it should be so I dug in to uncover the label. It was made in Jan 1997, but it had a 5 year tank warranty! Not too shabby, lasting 26 years without anode and still running great. YES, I ordered a new tank, but I went to the formerly GE appliance site (used to be employee of GE) and started reviewing specs and found one with SS elements, sensing anode, etc and 12 yr warranty.

 

[troutnut1]

Everytime I explain the reasons why my Bosch propane unit is in the recycle pile I get ton of arguments from folks that just love theirs, or want to sell people one, or had different circumstances. I suspect others may have had the same experience giving feedback so surveys like this might be biased in favor of them. We are back to conventional tanks.

But my Toto washlett toilet seat has an instant water heater built in and it is fabulous!

 

[lakehawk]

Water Heater

You may also want to check out the new heat pump water heaters. They are super-efficient and may qualify for a rebate.

https://www.energy.gov/energysaver/heat-pump-water-heaters

 

[Among_Primates]

I have had a Rheem tankless for the past 12 years or so, and it's been a disappointment ever since it went in. It takes forever to provide hot water, especially in the morning, and if you just go to a sink during the day... well, you may get hot water. Or you may get lukewarm water. Or you may get lukewarm water that changes to cold.

When I'm getting ready at the sink in the morning, I time things for the short period when the hot water suddenly appears, before it goes away again.

I've had plumbers look at the system, and spent a couple thousand diverting the gas line (that was one theory). Nothing worked, but fortunately this system is on its last legs. Also, I'm going to be selling the house this year. So one way or another, I'm going to be out of Rheem purgatory.

 

[Happyras]

You may also want to check out the new heat pump water heaters. They are super-efficient and may qualify for a rebate.

https://www.energy.gov/energysaver/heat-pump-water-heaters

Our current rebate is $500 from the utility. The sale price at HD is $1399, net cost about $900. This will be a larger tank than I would want, but the equiv. higher end elect tank is about $650. So it seems like a good deal until you think about it.

Where is the tank? If its inside your home it will put more load on your heating as it draws energy from your living space. While it may be efficient 1/3 the cost of electric only, that energy saved is taken from your living space will need to be replaced by your furnace or home heat source. I would have to do a heat balance on location, bust suspect a lower savings directly.

Now if it is located in a garage, the intake will be subject to air from that space which may not be clean and plug the intake filter. Shop saw dust, exhaust fumes, etc. In the case of a barn, the intake would quickly clog from hay dust for example. If you take air via a ducted intake, its more cost to install and will draw air at a lower temp. In the winter, some areas this would be below 30 F and efficiency would drop due to defrost cycling etc and lower COP at that temp.

Annual savings is typically stated at $200+ for a family of 4, this drops considerably when its only one or two in demand. Its not a simple decision, and certainly not worth it for lower demand conditions. Most of us are in that boat.

 

[Happyras]

I have had a Rheem tankless ...
I've had plumbers look at the system, and spent a couple thousand diverting the gas line (that was one theory). Nothing worked, but fortunately this system is on its last legs. Also, I'm going to be selling the house this year. So one way or another, I'm going to be out of Rheem purgatory.

My thought would be that the plumbers did not first adjust the flame gas control pressure to match the required inlet pressure at flow. Typically, I have done this for friends and family and upsized their piping from the meter to maintain gas flow with proper pressure. A 3/4 inch line is a minimum.

 

[meleana]

We have a Rinnai. We love it. Endless hot water. If you get a recirculating unit, the hot water is delivered almost immediately. You can program it via an app so that you can cut the recirculation during off hours - nighttime - to save energy. You will need to flush the system due to scaling once every year or two. We never run out of hot water and we feel it costs less overall with the programmablity.

We also have a Rinnai. Had it for 3 years so far in our new construction home. Took getting used to waiting for the hot water ( especially because we live in the Northeast), but we like it. It’s electric. We like it. Doesn’t seem to be expensive to operate.