# Indoor Tankless Water Heater



## Janderso (Aug 30, 2022)

Hey guys,
Our traditional water heater is original to the home. 22 years old.
We are considering a tankless, instant water heater. Do you own one?
Our current heater is natural gas.
We have solar panels and our Pacific Gas and Electric true-up has been about even.

The question is, should we go electric or stick with gas?

Thank you for your thoughts.


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## MrWhoopee (Aug 30, 2022)

I asked my plumber about tankless heaters. He said gas work fine, electric can't keep up. I don't have gas.


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## dbb-the-bruce (Aug 30, 2022)

Old house (30 years ago) installed a propane fired - no electricity needed - as my first on-demand HW. Loved it so much that when we built the new house (20 years ago) installed 2 natural gas, electric required for the controller units (Tagaki sp?). They work great and I love them.

At this point, I would not use anything other than on-demand heaters. We can have a house full of guests and everyone gets a hot shower when they want it. No wasted energy if we go away for a long trip.

Regarding gas or electric, I can't offer much advise - here in the NE our electric is pretty high and who knows where NG prices are going to be. 

If you were off grid, there would be / could be an advantage with solar electric and a large well insulated tank, as it would work as an energy storage device heating up when you have excess or abundant solar electric.


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## dbb-the-bruce (Aug 30, 2022)

MrWhoopee said:


> He said gas work fine, electric can't keep up


Thats one of the reasons I chose gas originally, but that was also 35 years ago.
I think that nowadays you can put individual on demand electric at the point of use and they do better at keeping up (esp. if you have restricted flow showers and drought conditions!)

Here in the NE gas would be the way to go. Our water from the city is pretty dang cold when it enters the house in mid January.


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## 7milesup (Aug 30, 2022)

@Janderso We have a  *Navien Tankless water heater* in our new house.  It does our domestic hot water and our in-floor heat.  It is, in a word, awesome.  It is considered a "combi" unit, whereas it does both DHW and the in-floor heat. The in-floor heat is an anti-freeze mixture, and because of that, there is no comingling of the domestic hot water and the in-floor heat.  We have zero issues with it keeping up.  I would never go back to a tank-style water heater.

Definitely go with natural gas.  Electric is expensive to install (massive current draw=large AWG wire and breaker) and expensive to run.

EDIT:  I have a small electric point-of-use water heater in my shop and don't care for it.  It barely keeps up even with a 40amp service going to it, and that is just for washing my hands and washing of parts, etc.  Our water from the well is quite cold in the winter, but for our gas-fired unit in the house, it is a non-issue.


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## Cadillac (Aug 30, 2022)

Elecitric  is most expensive to heat water. No electricity no hot water. Rolling blackouts you guys have = no hot water. Installed one 8yrs never looked back. Biggest downfall is getting up to temp farthest from unit.


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## Boswell (Aug 30, 2022)

I have two instant hot water heaters. One is electric, the other LP.  Both work just fine and both keep up with demand just fine. Like, others have mentioned, I would never go back to a traditional tank heater. I don't see any difference in usage between the electric (supplies to bathrooms with shower/tub and the LP that supports the kitchen sink, dishwasher and clothes washing machine.  a few things to think about when sizing. If you  "Oversize" the heaters, I don't think it will use more fuel (gas or electric) as they are controlled by a thermostat. The downside to "oversize" is the initial cost of the unit, any extra wiring for electric and also the MINIMUM FLOW RATE.  Both of my heaters require a minimum flow rate before they start heating. The LP heater is the smaller of the two and is never an issue. The Electric one supports a shower and I have found that if I restrict the flow of the shower to a minimum (we live on rainwater so water conservation is a daily focus) sometimes it will be below the minimum flow.  This does not have to be a problem, but just be sure to consider it.


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## FOMOGO (Aug 30, 2022)

I've had two of them over the years, both LP. The current one (Noritz) has been in around 20yrs and has worked flawlessly. The first one I put in was still working when I replaced it, but due to my hard water, it was having some corrosion issues. As Cadillac said wait time can be a little long if you are any great distance from the heater. Try to pick a central location if possible. Mike


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## mickri (Aug 30, 2022)

I thought about going tankless in my new place.  It is all electric.  No natural gas and a installing a propane tank would be a problem on a small lot.  In researching tankless electric water heaters it was recommended to set the water temp so you didn't need to mix in cold water to get the temp you needed.  I installed a 28 gallon electric water heater.  Fiddled with the temp setting to get it where I wanted it.  It is a little hot in the shower but fine in the kitchen and bathroom sinks.  Might turn it down some more.  Tankless is the way to go.  If you have long runs an undersink unit is sufficient for most usage.


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## Janderso (Aug 30, 2022)

I hadn’t thought of the power loss = no hot water. Fortunately we have only lost power twice in three years for a short time.
It looks like these inits are durable as heck.
Natural gas seems to be the ticket.
The initial consultation is tomorrow, I wanted some hands on experience before the introduction.

Thanks,
Jeff and Glenda


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## dbb-the-bruce (Aug 30, 2022)

Janderso said:


> power loss = no hot water


Yeah, that's what was awesome about the first unit I used. Was targeted for off grid / camp type of setting. It had some sort of ignition system that worked without electric power. In that house we mostly heated with a wood stove. It was awesome when we used to get the big snowstorms and lose power. The house was nice and warm AND we still had hot water. Anything that needed to stay frozen just went in a cooler outside. 

Would actually look forward to that happening.


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## benmychree (Aug 30, 2022)

We have a Takagi tankless water heater, can't be happier with it, it is on natural gas, and so was our old tank type heater, when we got the new one, our gas bill went down noticeably.


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## rabler (Aug 30, 2022)

Our house originally had gas, which was later converted to electric tank before we bought the house.  We are going to gas tankless, but our unit still requires electricity for control and ignition, relatively little electrical power but not easily lit with a match if we lost power, unlike a stovetop.

We have a tankless electric heater at the barns.  Mostly used for washing hands and winter feeding for old or young horses. To get enough heat for a shower there we went with a unit requiring a 70amp circuit.  The hot water is seldom used, and the barns are on a separate 200amp service mostly for a LED lighting so it was more reasonable to use electric than installing another gas meter and completely new service.  Definitely a situation where electric tankless was a win.


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## 7milesup (Aug 30, 2022)

rabler said:


> but our unit still requires electricity for control and ignition,


This is why I have a generator receptacle in my garage.  My portable generator will run everything in my house except the stovetop (induction) and the well (220v)  Other than that, my little 3500-watt generator will run my whole house.


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## silence dogood (Aug 30, 2022)

About 20 years ago, I replace the hot water heater. It is just an electric 50-gallon plain jane. At the same time, we added an inline filter. Have to replace the filter every year or when the city decides to work on the main line. The old heater is working just fine. Heck a lot cheaper and less hassle replacing a filter than a heater. If and when the heater finally goes, might consider the tankless.


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## Gnpenning (Aug 30, 2022)

7milesup said:


> @Janderso We have a  *Navien Tankless water heater* in our new house.  It does our domestic hot water and our in-floor heat.  It is, in a word, awesome.  It is considered a "combi" unit, whereas it does both DHW and the in-floor heat. The in-floor heat is an anti-freeze mixture, and because of that, there is no comingling of the domestic hot water and the in-floor heat.  We have zero issues with it keeping up.  I would never go back to a tank-style water heater.
> 
> Definitely go with natural gas.  Electric is expensive to install (massive current draw=large AWG wire and breaker) and expensive to run.
> 
> EDIT:  I have a small electric point-of-use water heater in my shop and don't care for it.  It barely keeps up even with a 40amp service going to it, and that is just for washing my hands and washing of parts, etc.  Our water from the well is quite cold in the winter, but for our gas-fired unit in the house, it is a non-issue.


My last house was the same, just different brand. Radiant heat with on demand hot water.  Fantastic system. Very efficient and cheap to run with natural gas. I will be doing it again on my next place.

Been fortunate to have natural gas everywhere I've lived and have never been a minute without,  Electricity, well that's another story.  Doesn't take much of a generator to run the controls for the NG system.


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## Dhal22 (Aug 30, 2022)

Plumber now for approaching 37 years,  self employed for 25.  My company installs 25 +/- tankless water heaters a year.   All Navien.  It's what I have a my house.


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## Aaron_W (Aug 31, 2022)

We installed a tankless water heater when we moved here in 2012. It is awesome, one of our first projects was replacing all the pipes under the house (a mess of PVC, copper, galvanized and iron pipe). It was 4am in February when we were finished so we were cold, damp and dirty. Not having to wait for the water to heat up alone was worth the extra cost.

We have a 2 bath house, so we could have gone with a 1-2 bath unit or 2-3 bath unit, we were advised to go with the larger unit to help cover for other hot water appliances. We have never had an issue with hot water, not even when somebody is taking a shower while the dishwasher and washing machine are going.



MrWhoopee said:


> I asked my plumber about tankless heaters. He said gas work fine, electric can't keep up. I don't have gas.



We have gas, but I've heard the same about electric not being as good as the gas units.



Cadillac said:


> Elecitric  is most expensive to heat water. No electricity no hot water. Rolling blackouts you guys have = no hot water. Installed one 8yrs never looked back. Biggest downfall is getting up to temp farthest from unit.



We have gas but unfortunately no electricity still no hot water because it is electronically controlled and electric ignition. Our gas oven won't work when the power is out either since it has an electric thermostat but we can light the stove top burners with a match.

The propane BBQ, Coleman camp stove and Jet boil (for coffee) have proven useful during power outages. Camping isn't just for recreation.


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## ddickey (Aug 31, 2022)

Cadillac said:


> Elecitric  is most expensive to heat water. No electricity no hot water. Rolling blackouts you guys have = no hot water. Installed one 8yrs never looked back. Biggest downfall is getting up to temp farthest from unit.


You need 120v to run the electronics on a gas unit. No electricity no heat with gas also.


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## Janderso (Aug 31, 2022)

rabler said:


> Our house originally had gas, which was later converted to electric tank before we bought the house.  We are going to gas tankless, but our unit still requires electricity for control and ignition, relatively little electrical power but not easily lit with a match if we lost power, unlike a stovetop.
> 
> We have a tankless electric heater at the barns.  Mostly used for washing hands and winter feeding for old or young horses. To get enough heat for a shower there we went with a unit requiring a 70amp circuit.  The hot water is seldom used, and the barns are on a separate 200amp service mostly for a LED lighting so it was more reasonable to use electric than installing another gas meter and completely new service.  Definitely a situation where electric tankless was a win.


70 amp!!!
Holy schnikies!


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## Liljoebrshooter (Aug 31, 2022)

Some of the bigger units will require 100amps.
Joe


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## Scra99tch (Aug 31, 2022)

I have always thought about doing a heat exchange system with a solar water heater on the roof.  

The idea being it would bring cold water through a loop from the well into contact with another loop via a heat exchanger that is connected to a solar water tank on the roof.  It would pump until the dummy insulated water heater in the basement reached temp of the tank on the roof.  This would then be connected to the main electric heater we have in the basement so that the water would already be hot enough to only use line power to bring it the further 20-40 degrees needed.  Instead of the temp difference of well water 32-48 to the 165 electric tank requirement.  The pumps would be powered by a solar panel or two.  Our electric water heater is the biggest draw on our bill and like a previous poster said our electric rates went real high here in NH.  I could probably do this for under $500.


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## Dhal22 (Aug 31, 2022)

Janderso said:


> 70 amp!!!
> Holy schnikies!




A decent electric tankless requires 100 amps.  In the milder climates...........


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## Janderso (Sep 1, 2022)

The plumber came out yesterday.
We have two options,
A tankless installed will run about $4,500!! It comes with a 15 year warranty.
A conventional is $2,200. It comes with a 10 year warranty.

Considering we may not stay in this home forever, we decided to go back with the conventional.

That’s a lot of money. I could buy a nice machine tool for $4,500


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## Cadillac (Sep 1, 2022)

Man prices have surely gone up. I got my tankless probably 10yrs ago from menards around the time that they really hit the market. I paid 599 for the unit it’s a Richmond I believe. Mine has double walled stainless for the exhaust. Those pieces were pricey luckily I only had about a 10’ run. All the test port and valving I might be in 800 bucks. 
 As for the power I have a 10k gen. I can count on one hand how many times my power has gone out in the 18yrs I been in the area. My gen runs the whole house except the AC so as long as I got some fuel I’m good. 
 I had read somewhere awhile ago that 30% of your bill goes to maintaining water temp.


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## Liljoebrshooter (Sep 1, 2022)

This is the exact situation all of us are going to face sooner rather than later.   You will have to decide whether to buy the green unit that costs 100% more or not.   Im kinda surprised that they even sell the ancient inefficient style out there.  
My LP fueled tankless heater was around $1800 about 10 years ago.  
I  figured we were heating water 24 hours a day and using it for maybe 1 hour a day. 
Joe


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## dbb-the-bruce (Sep 1, 2022)

Well.... The difference is 2K not 4K, so not so much of a tool -AND- if you do move you can add an extra $1000 to your house price!

The point being that you will save money (on energy) and add value to your home. Not taking issue with your decision you got to do what's right for you. If you are doing a cost benefit analysis do it accurately.

It's the same with buying machines and tooling. Cheeper may be the best immediate choice but is not always the best long term choice. I'd really like a better bench or knee mill right about now (mine is 5yo) - All my tooling is now R8 and I'm not going to get much for the miil I bought if I try to sell it. It would have been smarter to drop an extra 2-3K on my first purchase. Live and Learn.

If spending $2200 on the water heater means you can spend $4500 on tools then go for it!!


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## jwmelvin (Sep 1, 2022)

My summertime gas bill is $30-37/mo. Let’s say a tankless cuts that in half. For sure the water-heating cost is higher in winter because of colder incoming water, but even $30/mo savings takes a while to pay back the added expense. It does seem to, however, over the life of the unit, and offers some intangible benefits, so I’m leaning towards switching to tankless when our current 75 gal unit needs replacement.


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## mksj (Sep 1, 2022)

Our current house has two tankless water heaters, they are both located in the attic so they do not take up space in in closets on the main floor. Performance wise, they heat up the water almost instantly and you never run out of hot water. They do need a certain water flow rate to activate and most newer ones modulate the the flame/gas according to water flow and temperature. Tankless water heaters may fail over time because of mineral deposit build up, so they are often not recommend if you have high mineral content in your water. I looked at these when I lived in Tucson, and they were not recommended by the plumber. You also need to have a tankless water heater setup with diverter valves ($$) so it can be flushed with vinegar to remove the deposits every couple of years. Something I need to do on both of mine. Advantage of tankless is you should not have an issue with the water heater tank rupturing and you end up with water everywhere (which has happened to me twice through the years). Tanked water heaters should have their zinc anodes replaced every 5 years to prevent tank corrosion.

I would not go electric unless you have a lot of solar power generation and you do not get shafted from the electric company for peak demand electricity charges and/or time of use charges.  There may be some cost savings as far as gas consumption between tanked and tank less water heaters but I doubt that you would break even between the two  over 20 years of use. In the past when I had NG with dual tanked water heaters the gas consumption during the summer months was maybe $20-30 for both water heaters. If you had previous tanked water heaters and have the space, probably little value of spending an extra $1500 per water heater to go to a tankless. Repair on a tankless water heater is high should something fail, so also look at the warranty period and what is covered. Interesting point on tanked water heaters that I was told many years ago, was that there was little or no difference between lower cost and higher cost water heaters other than you are paying for a longer warranty on the premium models.


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## Janderso (Sep 1, 2022)

dbb-the-bruce said:


> Well.... The difference is 2K not 4K, so not so much of a tool -AND- if you do move you can add an extra $1000 to your house price!
> 
> The point being that you will save money (on energy) and add value to your home. Not taking issue with your decision you got to do what's right for you. If you are doing a cost benefit analysis do it accurately.
> 
> ...


You are correct, though I was using the figure as an example of it's buying power. Machine tools have gone up quite a bit of late as well.


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## Janderso (Sep 1, 2022)

mksj said:


> Tanked water heaters should have their zinc anodes replaced every 5 years to prevent tank corrosion.


Great idea!!


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## DavidR8 (Sep 1, 2022)

Janderso said:


> The plumber came out yesterday.
> We have two options,
> A tankless installed will run about $4,500!! It comes with a 15 year warranty.
> A conventional is $2,200. It comes with a 10 year warranty.
> ...


Holy crap! That's 10 times more expensive than the 40 gallon conventional gas unit I installed three years ago.


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## AllenHendey (Sep 1, 2022)

In my experience with on-demand/tankless units, the minimum flow rate issue Boswell mentions is a big nuisance. Basically you have to flow enough water through the unit to trigger its flow sensor and perhaps also to not boil the water in the heat exchanger... and so when you turn the hot down too much the unit goes off and your hot water runs cold. Of course the heater turned off a while ago and you didn't notice because there was still hot water in the pipe so when you turn up the flow again now you have to wait for that cold water to clear the pipe before you get hot water again.

Consider a heat-pump water heater: their prices have come down, and if you have a good location for one the amount of power used can be 1/3 or less compared to a resistance electric heater.

Flow rate issues aside, tankless units make the most sense when you use a lot of hot water (a tank unit just can't keep up) or very little, in which case the standby losses of a tank are worse than the lower efficiency of an on-demand unit. Last I did a cost/efficiency comparison, the tank units were both less expensive and more efficient for most residential applications.


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## MikeWi (Sep 1, 2022)

DavidR8 said:


> Holy crap! That's 10 times more expensive than the 40 gallon conventional gas unit I installed three years ago.


But that's also paying a plumber to do it. If you can do the work yourself it would be a fraction of that price.


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## Logan Novice (Sep 1, 2022)

Installed a tankless Rinnai about four years ago. Needed a larger gas supply line cuz the one for the tank type heater was too small. It took some getting used to cuz it takes slightly longer for the hot water to reach its destination but now that we know how to use it there are no complaints. We collect the first two gallons of water output for showers and dishwashing in a bucket and use it to water plants. By the time we run that two gallons through the line into the bucket the water is hot (we keep it set at 120 degrees) and it stays hot for as long as we could possibly want it. Turning the water on and off repeatedly does generate a momentary surge of cooled water, just like it did with the tank type heater when water in the line was left unused, but it gets back to hot pretty fast. All in all, I think it’s a good investment. We aren’t repeatedly heating up 40 gallons of water in the tank every day like we did previously and we have all he hot water we need. It does require flushing about once a year but that’s a simple task. Time consuming, but not complicated.​


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## Janderso (Sep 1, 2022)

DavidR8 said:


> Holy crap! That's 10 times more expensive than the 40 gallon conventional gas unit I installed three years ago.


I feel better.I looked up this exact unit from Home Depot. $1,986 plus tax = $2,128. ( Rheem Classic series, professional 50 gallon gas water heater)
$400 and change for professional installation and Bob’s your uncle.

Hey, don’t think I didn’t entertain the idea of buying one from Home Depot for $650 and doing it myself.
In my experience, they don’t last. I just don’t want to think about it.
I always did my own installs for everything back in my younger days.
My back is junk, it’s heavy, I’d have to get rid of the old one, ya da ya da.

I talked myself into writing a check 

This house has new solar, new 21 seer, four ton HVAC, new roof, new kitchen, new exterior paint job.
We wrote checks for all of it.
Much easier this way and we are buying piece of mind, I guess.


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## DavidR8 (Sep 1, 2022)

@Janderso I'm lucky in that my neice's husband is a master plumber so I'm able to buy on his account at the local plumbing supply. 
$400 for the install is about what he said he'd charge to install a tank.


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## ddickey (Sep 1, 2022)

You should've got a passive solar water heater then.


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## Aaron_W (Sep 1, 2022)

Janderso said:


> The plumber came out yesterday.
> We have two options,
> A tankless installed will run about $4,500!! It comes with a 15 year warranty.
> A conventional is $2,200. It comes with a 10 year warranty.
> ...



That is crazy, looking at Home Depot tankless are running $1000-1500. That is where we bought our current one, and it is coming up on 11 years of trouble free service. Now that I've said that I think I know what the next big appliance bill is going to be...  

I wonder how much of that $4500 is labor vs parts.


We installed ours in about 3 hours, maybe less. I found it an easier installation than a conventional, but we went with an exterior wall installation, so no exhaust ducting to worry about and it bought me about 3x3 of additional floor space in the basement kicking the old one out.


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## Aaron_W (Sep 1, 2022)

ddickey said:


> You should've got a passive solar water heater then.



Yeah, Chico gets hot, good candidate for solar.

My grandfather built his own solar pool heater in the 70s before that was really a thing. They kept the pool pretty warm for my grandmother and with the solar they barely needed to use the the pool heater after that. They lived there 40 years so I can only imagine what they saved on their pool heating bills over that time, for the cost of a couple hundred feet of ABS pipe.


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## Dhal22 (Sep 1, 2022)

Janderso said:


> The plumber came out yesterday.
> We have two options,
> A tankless installed will run about $4,500!! It comes with a 15 year warranty.
> A conventional is $2,200. It comes with a 10 year warranty.
> ...




Resale value,  a tankless will hold essentially 100% for years.   Potential home buyer's eyes light up when they see a tankless already in the house.   So really your tankless is free for a few years, the buyer will reimburse you later.


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## Dhal22 (Sep 1, 2022)

AllenHendey said:


> In my experience with on-demand/tankless units, the minimum flow rate issue Boswell mentions is a big nuisance. Basically you have to flow enough water through the unit to trigger its flow sensor and perhaps also to not boil the water in the heat exchanger... and so when you turn the hot down too much the unit goes off and your hot water runs cold. Of course the heater turned off a while ago and you didn't notice because there was still hot water in the pipe so when you turn up the flow again now you have to wait for that cold water to clear the pipe before you get hot water again.
> 
> Consider a heat-pump water heater: their prices have come down, and if you have a good location for one the amount of power used can be 1/3 or less compared to a resistance electric heater.
> 
> Flow rate issues aside, tankless units make the most sense when you use a lot of hot water (a tank unit just can't keep up) or very little, in which case the standby losses of a tank are worse than the lower efficiency of an on-demand unit. Last I did a cost/efficiency comparison, the tank units were both less expensive and more efficient for most residential applications.




Wrong in a lot of areas here.


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## Dhal22 (Sep 1, 2022)

MikeWi said:


> But that's also paying a plumber to do it. If you can do the work yourself it would be a fraction of that price.




We aren't cheap!


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## Eddyde (Sep 2, 2022)

Dhal22 said:


> Wrong in a lot of areas here.


Would you please elaborate on what you think AllenHendey said is wrong? We like to hear differing opinions here not conclusions.


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## Dhal22 (Sep 2, 2022)

Eddyde said:


> Would you please elaborate on what you think AllenHendey said is wrong? We like to hear differing opinions here not conclusions




Sure.   In what situation would you run hot water from a faucet so slow that the tankless would not fire up?  None really.   Ergo, it's NOT a 'big nuisance'.

There is no 'boiling' of water in a tankless heat exchanger.

Furthermore,  all of the above false premises does not create cold water that has to be purged.  

There is/ used to be a cold water sandwich issue but tankless units that we install have a buffer tank to eliminate that.

I'm speaking from 37 years in the plumbing trade,  25 years self employed,  10-12 employees and dozens and dozens of tankless installs annually experience.


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## jwmelvin (Sep 2, 2022)

Dhal22 said:


> There is/ used to be a cold water sandwich issue but tankless units that we install have a buffer tank to eliminate that.


This has been my biggest concern. What size buffer tank do you use?


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## Dhal22 (Sep 2, 2022)

Navien has a built in buffer tank.  And a built in recirculation pump if you choose the correct model.


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## jwmelvin (Sep 2, 2022)

Dhal22 said:


> Navien has a built in buffer tank. And a built in recirculation pump if you choose the correct model.



Oh that seems great. Thank you.


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## Dhal22 (Sep 2, 2022)

jwmelvin said:


> Oh that seems great. Thank you.




We install 25 or so Naviens a year.  Their recirculation pump technology will learn your usage patterns and will turn itself on accordingly.


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## jwmelvin (Sep 2, 2022)

Dhal22 said:


> We install 25 or so Naviens a year. Their recirculation pump technology will learn your usage patterns and will turn itself on accordingly.



I was just looking at their combi boilers, as I use heating hot water too, for certain forced-air zones and hydronic floors. Existing boiler is old cast iron, inefficient. Current 75 gal WH is 10+ yrs old. Replacing both with one appliance sounds good.


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