OT: who has made the switch to tankless water heater?

[Climb01742]

i'd love some real-world opinions here.

our house has a traditional hot water heater tank and its at the end of its warranty and probably close to its lifespan.

we're trying to decide between replacing it with another tank-style water heater or go with a new tankless system.

i've researched all the, in theory, pluses and minuses of each option. certainly the upfront cost of a tankless (even with rebates) has me being cautious.

for those of you who have gone with the tankless systems, what's been your experience? good/bad? happy you did? anything to look for, or avoid?

many thanks in advance!;)

[Don49]

I was in your situation about three years ago and ready to try tankless. My trusted plumber couldn't install a tankless in the same location as the old tank, so I would have had to relocate the tankless to an outside adjacent wall at considerable extra expense. The issue was the heat from the vent was too high to run the vent pipe through the structure where the old one went.

So that was a show stopper for me, but that issue could be resolved with newer models.

[Ken Robb]

Check maintenance requirements for both. We are supposed to drain water from our tanks at regular intervals to minimize sediment build-up in the tanks but few people bother to do so. This "insulation" in the bottom of the tank reduces efficiency over time.

The tankless ones probably need some routine service as well and may not be as tolerant of owner sloth as the old-fashioned ones.

[Jaq]

The last time I had a hangover, it was the Hangover To End All Hangovers. So I spent two solid hours under an unending hot shower thanks to a tankless water heater.

When it comes time to replace my heater, I'm going tankless.

On a side note, a friend's massive tank just blew out, turned his garage and a part of his house into a swamp that now reeks of mildew. No thanks.

[verticaldoug]

I have a log house in the mountains of Hakuba Japan. I built the home with a tankless heater in 1999. The winters are very cold and very snowy. No problems after 13 years with basically zero maintenance. I'd have to check the manufacturer although I am guessing either Rinnai or Noritz. I run on propane.

[Louis]

You guys are all wusses. My water heater (tank style) has been turned off for well over a month. HTFU. ;)

[verticaldoug]

You guys are all wusses. My water heater (tank style) has been turned off for well over a month. HTFU. ;)

When will the Sheriff show up to move you out?
:banana:

[Louis]

When will the Sheriff show up to move you out?
:banana:

It's off because I turned it off, not because I haven't paid my bills... :p

[texbike]

When we redid our last house, we used an electric tankless water heater and it worked great for the small application that it was used for (1200 sq ft house with the bath, kitchen, and laundry within 40 feet of each other).

However, there were some service issues with the unit. The first was a circuit board that went bad and the second was a bad heating element. In both cases the company overnighted replacement parts to us under warranty once a diagnoses was made. The problem was that the warranty didn't cover the expense of the plumber. We ended spending MUCH more than anticipated on the thing for that reason. However it worked great when it worked.

I would definitely consider another one and may do so on our new house. However, this time it would be gas-powered instead of electric.

Texbike

[CaptStash]

Check maintenance requirements for both. We are supposed to drain water from our tanks at regular intervals to minimize sediment build-up in the tanks but few people bother to do so. This "insulation" in the bottom of the tank reduces efficiency over time.

The tankless ones probably need some routine service as well and may not be as tolerant of owner sloth as the old-fashioned ones.

Coming up on twelve years with our tankless heater. So far no issues, and no (as in zip, zlich zero) maintenance whatsoever.

Positives: Unlimited hot water, very long (lifetime?) warranty, lower energy costs, doesn't use energy when not in use, tiny footprint.

Negatives: Limited throughput - maximum two showers at any given time, not compatible with a recirculating instant hot water system (see below), high up front costs, seems to take a little longer to get hot water.

On the recirculating system: A stock recirculating system will void the warranty. The way around this is to install a small (usually electric) under the counter type of tank hot water heater to be used for the recirculating system. The small heater keeps the hot water recirculating to the outlets. When hot water is called for, the tankless heater kicks in. I haven't installed the system, although my house is plumbed for it 0- just haven't gotten around to it. Depending on your energy v. water costs, it may not be worth it. Here in Seattle, energy is stupid cheap, and water is bizarrely expensive, so it would probably be worth it for me to do.

I know that there are also some other options for recirculation systems that are now available.

CaptStash....

[MattTuck]

No direct experience, but I watched a "This Old House" episode maybe a year ago in which they discussed a hybrid system...

The tank was 3 gallons, if I recall correctly, and solved some of the issues about delayed hot water...

let me see if I can find the clip.... yep, the internet is awesome. Here's the episode. Start it at 16 Minutes in.

http://www.thisoldhouse.com/toh/tv/video/0,,20561318,00.html

[Willy]

We changed over 4 years ago and I would not want to go back. Gas bill went down substantially with the only downside that you have to wait a little longer to get the first hot water. The unit is on the outside face of the house so we gained back a closet. The old way seems silly to keep a full tank of water hot when you only need it a few times a day.

[BSUdude]

One thing to consider is your water supply. If using a municipal water source (at least ones like we have in Indiana) and you don't have a water softener, the calcium chloride in the city water will eventually clog up the tiny lines inside the water heater that allow it to heat the water "instantly," giving your tankless water heater a functional working life of only a few years. At least this has been the experience I've heard of people having with them in my area. Different types of units may have different vulnerabilities, etc...

[Climb01742]

the knowledge and experience resident in our little forum never cease to amaze and impress. thank you all for your replies so far.

[SlackMan]

Another very satisfied tankless user. Nine years and counting with no issues at all. We have a Rinnai. It was cheaper when building our house to put in one tankless vs. two tank heaters, which would have been the norm for our size house. I do know there can be issues with retrofitting, especially if going from two tanks to one tankless. If there were no difficulties in switching, there is no way I'd go back to tank.

[1centaur]

My business partner is extremely anal about researching things like this (including calling manufacturers to chat with them) and concluded that the system delays in adjusting to different people using water in other parts of the house while he was taking a shower would drive him crazy (little bursts of colder water as the load was adjusted).

I think if he lived alone he would have found it ideal.

[54ny77]

operationally, they suck.

unless you retrofit each important room/floor with additional pumps to increase speed of hot water getting there.

then they don't suck so much.

operating costs are great, however (natural gas bill went down by about half), provided they don't break down.

pricey to get started though. worth it? eh, not really, unless you have a huge place and/or hot water use.

[cnighbor1]

1. They are used in Europe for one
2. You don't have a tank full of hot water waiting till you need which requires constant reheating just to be ready for a need
3. Your leaving a lot of hot water cooling in the pipes required to get the hot water from a tanks to spot that needs it
4. GE has a new type of water heater which looks interesting
5. tankless water heaters requires a vent so that can be a problem
6. switch to gas water heater if electric Reduces energy costs

[pbarry]

I installed a few Bosch natural gas units several years ago. The customers were really happy with them. The hardest part was getting the venting correct and to code.

On traditional tank heaters: Yearly draining is a good idea. An often forgotten maintenance protocol is to remove the anode every 2-3 years. It serves a similar purpose as a zinc on the hull of a sailboat: Hard water deposits are attracted to the AL anode, and less of them end up in the interior of the tank or in your lines. They can be scraped clean and re-used, but replacements are not expensive. When they've quit working due to build up or deterioration, modern ceramic faucet valves can start leaking because of deposits no longer captured by the anode. The last one I replaced took calls to three plumbing supply houses. There was only one, (these have a universal thread with varying lengths), in the Boulder area. Plumbers don't seem to be servicing these. Install a new heater and replace when it goes... Replacing the anode is old school maintenance that can greatly extend the life of your H2O heater.

[Louis]

One option to minimize energy costs with a tank-type heater could be to improve the insulation at the tank and along the pipes. Low cost and easy to do yourself.

During the winter you're not wasting that much energy, since it will contribute to heating the house (although the heat may be in an area where you really don't need it, like the basement). The real killer is in the summer where your A/C has to fight against the losses from the heater. However, at this time of year the location probably helps, since you won't be using that much energy to cool the basement or closet where the heater is probably located.

[pbarry]

One option to minimize energy costs with a tank-type heater could be to improve the insulation at the tank and along the pipes. Low cost and easy to do yourself.

During the winter you're not wasting that much energy, since it will contribute to heating the house (although the heat may be in an area where you really don't need it, like the basement). The real killer is in the summer where your A/C has to fight against the losses from the heater. However, at this time of year the location probably helps, since you won't be using that much energy to cool the basement or closet where the heater is probably located.

Yes! Insulating hot water pipes can save you a bundle on energy costs. Get 3/4" closed cell pipe insulation for your diameter pipe. Available at a plumbing supply house--they may have to order it. Don't buy the self stick stuff from Home Depot. On new installations, it's super easy to slide uncut 10' lengths over the pipe as you go, bends and all. To retrofit, you have to use foam that's split on the side and miter for angled joints. Then glue the seams, miters, and butt ends with contact adhesive.

[SlackMan]

My business partner is extremely anal about researching things like this (including calling manufacturers to chat with them) and concluded that the system delays in adjusting to different people using water in other parts of the house while he was taking a shower would drive him crazy (little bursts of colder water as the load was adjusted).

I think if he lived alone he would have found it ideal.

Not to say this can't happen, but I've never experienced it in our house with other people showering or dishwasher running. I tend to be anal about researching things too, but on this question, I'm going to go with experience over theoretical outcomes.

[Onno]

We've installed two, and have been very happy with them. Depending on where you put them, you have to wait longer for the hot water. We went with them because it just makes sense not to be heating 40 gallons of water when you are not using it. And tanks will leak. And they are on the ground, where they can get damaged by flooding. Both of ours (in two houses) were installed in less than half a day.

[rustychisel]

been using them for over 20 years, gas, no problems except on the older flow through models the pilot light occasionally blew out. Otherwise very good.

Here, with a milder climate they make sense, but our energy company also uses different tariffs for day/night/peak times.

I'd second the comments about water quality. In some parts of Aust plumbing will corrode out in 2 years. Not here.

[classtimesailer]

We put in TWO Takagis about 8 years ago. They didn't recommend a circulating pump when we took delivery but it took minutes for water to get upstairs and had to put pumps on each heater. Now they tell you to get a pump from the start. The pump effectively creates a tank out of your pipes which defeats some of the benefits of going tankless. The new ones avoid some of the ventilation issues we had.
They are not guaranteed to last any longer than a tank. (check the fine print. I think its the heat exchanger that has a short life expectancy). If you decide to do it anyway, make sure that you have enough gas. You need a big meter and 1 inch pipes.

If I built another new house, I'd put a small one near the Kit/Laundry and another larger one near the back to back side to side on top of one another Bathrooms.

[technicolor]

We installed 3 of them (triplex) when we remodeled a few years ago. Same experience as others. Love the reduced energy usage, love the unlimited hot water, smaller footprint, etc. But you will wait for it to get hot. Can't imagine going back to traditional setup.

[Louis]

I've been holding back from saying this, but personally I think the "unlimited hot water" thing just encourages people to waste water. Granted, if you have 10 kids and all have to take showers within a short period of time that may be an issue, but how many families have 10 kids? I'd think that two 40 gallon tanks ought to be plenty, even for the largest of families?

Do you turn the water off while soaping up?

One minute to get wet and wash my face. Turn off water. Lather up. Run water for 5 seconds to get hair wet. Lather up hair. Turn on water. 5 minutes of rinsing. Done.

That's 6:05 of water use. And unless it's the dead of winter and freezing in the house, I don't wait for the hot water to get to the shower (assuming the water heater is even on). Just use what's in the pipe.

[Tandem Rider]

You need to look at your hot water usage honestly. If nobody is home all day every day and all dish washing, laundry etc. is done at once it MAY make sense. If someone is home all or part of the day and laundry, dishes, showers etc. happen intermittently all day then standby losses are a non-issue.

Burner efficiencies are pretty close between gas fired tankless and tanks. For example, if a household spends $30 per month on heating water (not cooking, space heating, gas fireplace, grill etc.), that is $360 per year, 5% increase in efficiency is saving a whopping $18 per year.

If you have a water boiler for comfort heating it may make sense to use an indirect waterheater. Modern condensing boilers are 92%+ efficient and an indirect heater will outlast several waterheaters, conventional or tankless while using the often more rubust boiler as a heat source.

[Cat3roadracer]

Natural gas powered Rinnai for us. One of the best moves I have ever made. Highly recommended.

[MattTuck]

Louis, you are the shower equivalent of a Belgian hardman.


I've been holding back from saying this, but personally I think the "unlimited hot water" thing just encourages people to waste water. Granted, if you have 10 kids and all have to take showers within a short period of time that may be an issue, but how many families have 10 kids? I'd think that two 40 gallon tanks ought to be plenty, even for the largest of families?

Do you turn the water off while soaping up?

One minute to get wet and wash my face. Turn off water. Lather up. Run water for 5 seconds to get hair wet. Lather up hair. Turn on water. 5 minutes of rinsing. Done.

That's 6:05 of water use. And unless it's the dead of winter and freezing in the house, I don't wait for the hot water to get to the shower (assuming the water heater is even on). Just use what's in the pipe.

[nicrump]

Installed my own(to code) outside, 6.2gpm natural gas. I have a ~1320'sqr one bath and it is outstanding. The one setback was an undersized gas line that caused issues early on but when I took the instructions seriously and upgraded the line to 3/4", all was fine.

I chose outdoors to avoid venting issues.

If I were building a new house I'd seriously consider installing multiple smaller(2.3gpm) electric units at each point of use. ie one in each bath and one at the kitchen. The newer electric 2.3s are very compact and require no venting.

As for maintenance, it is recommended that you annually connect a recirculating pump and run diluted vinegar much like you do to a drip coffee maker. 5 years on I haven't done it. My water is typically 3 grains so not to hard. Much harder and I'd probably buy a re-circ pump and do the maintenance.

[Steve in SLO]

We've got a 1200 sq ft cabin with 1.5 baths. Nick's 2.3 gallon point of use suggestion sounds great for that...one downstairs to heat the kitchen and half-bath, and one to heat the upstairs full bath. That will basically eliminate our $400 annual '40 gallon kettle warming' propane cost.

[Louis]

Louis, you are the shower equivalent of a Belgian hardman.

All I know, is that at times of the year when the water heater (electric) is on but I'm not running my A/C or my heat (much of which is provided by electric resistance heaters) or the basement dehumidifiers, my electric bills are about $40 / month. Therefore, a 40 gal water heater used by one person can't be using that much power.

(I also use cold water and cold water detergent, not hot, for the laundry - just let things soak for about 30 minutes half way through the cycle, and they turn out fine, including all the bike stuff, which also get some Borax laundry booster)

[dumbod]

It's an attractive option but there can be an issue that didn't occur to us until we decided to switch to tankless. Assuming that you want to install an electric unit, older houses may not have sufficient wiring to carry the required load. You can change the wiring but that radically changes the cost. Our new heater has a tank.

[93legendti]

Thought I'd resurrect this thread....

We are having some problems with our water heater. Our plumber suggests a tankless system. A friend in NY who sells them doesn't recommend tankless.

Are people still satisfied with their tankless gas water heater?

[572cv]

Some contributors to this thread recommended quantification of the water quality in your system. I concur.

If you are replacing hot H2O, and also have a boiler that has been in operation a long time, consider replacing the whole shebang with high efficiency boiler with a domestic H2O hotwater tank. My combined unit is from Triangle Tube. The water tank is only 13 gallons, seems to work well for family of three. Heats up well, doesn't keep that much water warm, so more efficient, and the boiler can keep up with demand as if it were instantaneous, which it kind of is. It's another approach.

[zap]

Spoke to a plumber during the holiday's and he told me it would cost several grand to install and tankless water heater. I was surprised by that.......if true certainly not worth $2 savings a month.

[Climb01742]

Thought I'd resurrect this thread....

We are having some problems with our water heater. Our plumber suggests a tankless system. A friend in NY who sells them doesn't recommend tankless.

Are people still satisfied with their tankless gas water heater?

We ended up replacing the old conventional water heater with a new conventional, though far more efficient, water heater. After looking into going tankless as a retrofit for an older house, it became clear that it would be more work/hassle than necessary. But...if we were building a new house, tankless would be the choice.

Adam, are there any rebates/tax incentives in Michigan for replacing older systems with newer, more energy efficient ones? Might offset the cost some?

[93legendti]

We ended up replacing the old conventional water heater with a new conventional, though far more efficient, water heater. After looking into going tankless as a retrofit for an older house, it became clear that it would be more work/hassle than necessary. But...if we were building a new house, tankless would be the choice.

Adam, are there any rebates/tax incentives in Michigan for replacing older systems with newer, more energy efficient ones? Might offset the cost some?

That's a good question. Our plumber, who is too expensive, quoted $3k to install. No thanks at that price...

[11.4]

We had one installed in a 2500 sq ft 3 BR home, total cost $1900 about six months ago, and had one already installed in a recent guest room addition that we rerouted to serve the kitchen as well (see below). Most of what was said in this thread is very valid, so just a few points to add:

1. Whoever talked about venting, in a tankless unit you want gas rather than electric, and that means venting.
2. Since these units have such a small footprint and it can be located overhead, we put both above the ceiling, one serving a guest bedroom and the kitchen (the guest bedroom is rarely used so it basically is dedicated to the kitchen) and the other to the other two bedrooms. Pipe lines are less than ten feet to appliances or to bathrooms, and are insulated and are also run through the attic so they keep warmer compared to sub-floor. Location is critical to a good installation. I saw one that was installed in the top of a washer/dryer closet right next to the bath and was virtually instant and very efficient. The longer the distance, the more it helps to have more capacity.
3. The intermittent delivery with multiple users is driven more by distance again.
4. A smaller storage tank was something we actually tried out, but we found that with good location, the tankless unit did just fine. We also installed an instant hot water booster tank under the vanity sink in the master bath; it gives an extra boost with blazing hot water within a couple seconds, but it's really a luxury since we got hot water within 15 seconds maximum from the overhead tankless unit.
5. Our installer recommended a pre filter to remove calcium and other minerals. It has a $14 cartridge we replace every six months; we haven't had the system long enough to know if it made a difference, but we have very high mineral contents in our water.
6. We got some substantial local energy credits from our power company for installing the system. Over a year, about $700.
7. The whole gas tankless system does need maintenance. People think of water heaters as never needing service, as pointed out by others above. Tankless heaters are the same. The gas heating system needs cleaning and adjustment just like a regular gas furnace does, and the tank still accumulates some sediment just like a traditional tank heater. Our installer found quite a bit of mineral deposits in the older preexisting tankless unit, and cycled it with a dose of Finish dishwasher mineral deposit remover. It went from looking pretty messy to bright polished stainless inside and flow was much better. Interesting trick.
8. Just in case anyone wasn't familiar with hot water needs, a washing machine needs a hot water supply line but a dishwasher doesn't (it heats its own water). So when you're planning, the kitchen isn't that much of a big hot water user if, like most people, you use the dishwasher to do your major dishwashing and at most rinse stuff off under the faucet. In short, plan your hot water tank location around bathrooms, not the kitchen. That will also make the flow more consistent for the bathrooms.

I definitely am happy with the tankless heater(s) and while I know that they are more expensive to service and replace, if they get good maintenance they are very durable. Maintenance is really the key so if you don't want to service it properly (easy things you can do yourself) you might think harder about a traditional tank that you can just replace inexpensively. But the performance of the tankless systems, if they are smartly located and installed properly, can't be beat.

[PQJ]

The only gripe I have with mine is its distance from my master bathroom - it can take 60 - 90 secs for hot water to flow. It's a bit of a pain but not nearly enough to have me regretting the decision. Literally the only thing wrong with it. Brand is Rinnai.

@ 11.4 - what sort of maintenance would you recommend?

[EPOJoe]

When we moved into our current place around five years ago, we inherited the system you see below, which was installed five years before that. The world's most complicated hot water system. I've had two plumbers in here, and neither could describe to me exactly what was going on with the water flow. Just after we had moved in, the tankless unit started making some horrible screaming sounds, and developed a slow leak. Had a small part replaced, and it was good to go for another year until the heater core started leaking and we had to replace the core at a cost of around $700.00. Since there was a recirculating pump installed, the warranty was void, and we were stuck with the full cost of replacement. The electric timer is there to shut off the recirculating pump during no-use periods so the tankless system gets some "rest" and the new heater core will hopefully last a bit longer. As you can see, a smaller storage tank was installed, with the idea being that the tankless unit maintains the temperature in the tank, really just turning the tankless unit into a boiler. I'm not sure if I would have set this up like this if I did it, but after those two repairs on the tankless, everything seem to be fine. Note the water alarm on the ground in the plastic container (there are actually two alarms down there). After the two leaks we've already had, I don't trust any of this stuff.

[93legendti]

The only gripe I have with mine is its distance from my master bathroom - it can take 60 - 90 secs for hot water to flow. It's a bit of a pain but not nearly enough to have me regretting the decision. Literally the only thing wrong with it. Brand is Rinnai.

@ 11.4 - what sort of maintenance would you recommend?

Our showers and tubs are on the 2nd floor and our water heater is in the basement. It takes us a good minute to get hot water upstairs. I wonder if it would be worse if we went to a tankless system...I will ask the Hvac/water heater guy who is coming out Wednesday. He isn't a fan of the systems.


We have 95% efficiency furnaces on either side of our existing water heater and they already have venting...

[NHAero]

I'd expect the tankless to take slightly longer to get the hot water to the 2nd floor bathrooms than a tank-type heater. Note that the gas line size may need to be bumped for a tankless.

If you're tired of the long wait time, look into a demand recirc system, which can be retrofitted but the plumber has to pay attention to the directions.

http://www.gothotwater.com/

Our showers and tubs are on the 2nd floor and our water heater is in the basement. It takes us a good minute to get hot water upstairs. I wonder if it would be worse if we went to a tankless system...I will ask the Hvac/water heater guy who is coming out Wednesday. He isn't a fan of the systems.


We have 95% efficiency furnaces on either side of our existing water heater and they already have venting...

[93legendti]

I'd expect the tankless to take slightly longer to get the hot water to the 2nd floor bathrooms than a tank-type heater. Note that the gas line size may need to be bumped for a tankless.

If you're tired of the long wait time, look into a demand recirc system, which can be retrofitted but the plumber has to pay attention to the directions.

http://www.gothotwater.com/

Thanks. The wait times don't bother anyone. I usually floss while waiting for the water to warm up. We shall see what my service man says Wednesday about our existing water heater.

[pdmtong]

If you're tired of the long wait time, look into a demand recirc system, which can be retrofitted but the plumber has to pay attention to the directions.

we put in a recirculating line and in-line timer driven pump years ago. works great. hot water in the mornings almost instantly. yea, its only 40d in SFBA in the am but remember cold is relative. I lived in minus zero Chicago so I get what single digits and below are all about.

tankless is interesting to me, given my instant hot tank under the kitchen sink, but I am not willing to redo all the plumbing in an older home to accommodate.

if I was building new, sure. but not retro. then again, around here, if I was building new, I would also be ordering a Sarto with EPS and Bora ultras...but, sadly, I am NOT.

[93legendti]

Our kitchen sink is right above our water heater. The water gets too hot, too quickly...:)

[paredown]

Our first experience with tankless was not a full success--it was a full house Bosch unit purchased online. Our plumber was first-rate, although he had not done an install before, it worked a treat. You could run the dishwasher and the shower at the same time, and not notice. (Could not clamshell onto an outside wall, so we had to go up, through attic using the proper insulated steel vent pipe).

Then we had troubles--and there were no qualified service people within a 100+ miles, and we could not get anyone out to service it. I ended up figuring it out, but I would make sure that whoever is installing a tankless knows how to service--and that the unit has a good warranty.

We planned to go tankless again on this house (and didn't for budget reasons)--put in a used conventional instead. Our plumber had spec'd a Takagi--which he had good experiences with and that he was getting from a wholesaler that stood behind the warranty. (Rinnai is also good, and the high-end Triangle that someone mentioned also gets good reviews.)

If your heat is hot water, I love the combi-boiler idea. For the Habitat house we are working on, we will install a single on-demand water heater that will service potable h/w and heat demands (great for a small house), but for a larger house, you will probably need a boiler/reservoir for either or both systems. There are also some pretty slick hot air systems using on-demand with a H/W heat exchanger.

Water quality is a issue--around here, the answer is an annual flush and inspection, but the savings on H/W, the limiting of floods from a ruptured tank (especially if your tank is next t0 the living space like ours)--and the fact that there may be incentives (for us, Orange and Rockland currently has a decent rebate) makes it worth serious consideration.

You can also add the water line insulation to the on-demand and speed up the H/W arrival.

[notsew]

If your heat is hot water, I love the combi-boiler idea. For the Habitat house we are working on, we will install a single on-demand water heater that will service potable h/w and heat demands (great for a small house), but for a larger house, you will probably need a boiler/reservoir for either or both systems.

We have this in our house with radiant heat throughout. The hot water runs through the slab and keeps the whole place toasty warm. As for the on demand water, there is one big upside - never ending showers, and one big downside - waiting for hot water.

It can take a loooong time to get hot water to any of the faucets if the heat isn't on. Like (what feels like) minutes. Oh, one other upside, our gas bill has never broken $60.

Can't really speak to the economics as a refit, as this was new construction.

[F150]

I was associated with the installation of a 380,000 BTU natural gas fired A.O. Smith tankless unit as part of church renovation project while Chair of Trustees. Didn't crunch numbers to justify the switch, in part due to a great deal on the unit. Unfortunately, the mechanical contractor charged $5,000 to install. b/c of location (former hot water boiler room now used for storage) with respect to outdoor A/C units and some other factors, required more costly fresh air supply and exhaust ducting, extending gas pipe, etc. I figured why hold 80-100 gallons of hot water all week when dishwashing after Wednesday Night dinners was our largest usage. One year of operation w/o issue. Hopefully 15-20 more to come, and our hard water doesn't shorten that.

Now if I can just get the women to quit laying combustibles against the cabinet...