I think we talked about this before, but it looks like my water heater is about to die on me (and regardless, it is very old and inefficient, and just needs to be replaced), so I am looking at Demand heaters. My natural inclination is to go with the gas, because any electricity around here is generated by coal. Do you all have any experience with this sort of thing? I have no dishwasher, and it is just me, so I am thinking if I go with a middle of the road size, I should be fine. Any suggestions or tips? Any brands that you find reliable? And will this save energy?
by John Cole| 70 Comments
This post is in: Open Threads
No info on brands or anything, but we’ve always had a gas water heater. One of the upsides if if the power goes out, you still have hot water. During Katrina, we invited several people we knew to come shower at our house. (which is way less dirty than that sounds)
Boil some water and pour it in a big tub. It was good enough for Richard Lionheart.
You’d be better off getting a recommendation for a good, honest plumber in your area who can outline your options than general recommendations here. Matching up your needs with what’s available is more like getting married than buying a toaster.
mem from somerville
I attempted to get an on-demand heater last time my tank failed. But I had installation issues. It would require extra piping for locating it, as the vent needed to be at a certain height and on a certain wall to the outdoors. Further, because my exterior is brick, the venting was going to be a bigger problem. My basement windows weren’t high enough for the code.
So I’m saying there are additional issues. You should get estimates and talk to someone who has installed them to code elsewhere.
I wish I could have done it. But alas. Not for me and my particular old house. I have solar hot water now instead.
I had a demand heater when I lived in Japan. I think my apt had 2: 1 for the kitchen and 1 for the bath. They worked well and ran off natural gas. I liked them, and they were quite reliable. It also made me more conscious of energy usage to hear the whoosh of the heater start up when I turned on the hot water.
Do you heat your house via hot water radiator heating?
I’ve heard they do save a lot of energy, with gas being cheaper to run in most places than electric. One thing you have to take into account is the hardness of your water; hard water supposedly hampers the operation of an on-demand heater.
We installed a solar hot water heater back in 2007, and it has saved us a huge amount of money in oil bills, even here in non-sunny Vermont.
If you’re going to get an on-demand water heater, make it gas powered. The electric ones require a gazillion watts of power.
@mem from somerville: Don’t you just love the solar hot water heater? It’s a wonderful thing to hear the water being pumped through the panels on those single-digit days in January. Every day the sun shines I feel like I’m getting money deposited into my bank account. If I had the money I’d install a solar PV system too.
If you get a demand heater, something I would never do, how long before we get the post about the water not being hot on demand?
Gas water heaters are great.
A licenced plumber can tell you about what hot water heater is effecient etc.
You should consider solar systems, too. It’s much simpler than solar electric systems, but can save most of the money you’d otherwise spend on hot water.
I’ve got an on demand gas powered hot water heater and I’ve been very satisfied with it. It’s installed outside, so I have to be careful when it gets cold, but generally in Seattle it is not a problem. Ballard Natural Gas was great.
@jacy: This is a good point. I had a house guest during the 1977 blackout (NYC) and in the morning I offered to make breakfast. My guest looked surprised at the idea and said “but there’s no power.” I said, “the stove is gas. I can still cook.”
There are other options if that’s your main argument for gas. I’m guessing that anyone in Cole’s neck of the woods will be able to do some cooking over an open fire in the event of a power outage. That’s not a practical option for a condo dweller like me, but I do have a propane camp stove as part of my emergency kit. I’d count a long power outage as enough of an emergency to justify breaking it out.
That aside, go with gas if it’s available. Electricity is only a reasonable option for a water heater if it’s cheap hydroelectric power. Otherwise, you’re just paying for transmission losses.
mem from somerville
@beltane: absolutely delighted with it. I am always stunned in mid-winter when I look at the panel temperature.
I also have a 2-family house and we plumbed both of the back-up heaters with the water from the giant thermos tank (whatever that’s called). So we have 2 households benefiting from that single panel.
It was pricey though. By far the most cost-effective energy saver I did was the wall insulation. And it turned my drafty old New England house into something toasty and nearly unrecognizable….
With an on-demand water heater you will still need enough power to operate the ignition controller (at least that’s the case with mine). It’s not like a gas tank heater in that regard.
I’ll third the recommendation to get a good plumber to lay out your options. And be sure to ask about rebates.
Definitely gas. Electric units would have a HUGE heating element. One thing to keep in mind is that at low flow values (say—just the kit sink) it occasionally wont activate the unit. They generally require 0.6 gpm to activate. (The hw on a kit sink will generally require this at full whack) The better units (Rinnai is a good one) seem to be less susceptible to this. If the cost difference isnt much, I’d go for the full btu rating (generally 180,000+)
@Roger Moore: It was more an anecdote along the lines of what Jacy said. My guest came from an area where most houses were all electric and she was not familiar with gas stoves except for propane or camping stoves.
I can only comment on my experience with demand water heaters. I shared an apartment in Italy 20! Years ago with four other 20 year old females. We NEVER ran out of hot water. Demand heaters are wonderful. Now that I have three teenagers, I wish I had one. Sigh.
I have a Bosch Aquastar demand heater purchased online
I’m capable of doing the plumbing to install one.
I agree that activation takes some getting used to; need a sufficient flow before it kicks on, and safety features mean if you don’t activate it you need to shut water off for 30 seconds before you can try again.
Recommend the Bosch. It’s easy to use and cheap. When we remodeled, we put one next to the showers/washer end of the house and the tiny one next to the dishwasher, for a total cost of ownership payback of 34 months.
The cold water runout costs of a tank heater are probably not significant where you live, but I hate the thought of all that potable water running down the drain.
Gas is more efficient to move around the country than watts are. Also we in Western coal country don’t mind the environmental impacts of extraction nearly as much as we mind WV being leveled.
Have no clue as to what to recommend, but should note that even though it’s just you now, you should replace the water heater with one of an appropriate size for your house and the reasonable number of folks that might live there (after you sell it).
Sounds like you currently have an electric water heater. It’s not hard to change the heater element in an electric water heater. You can buy them at Sears. The biggest problem, however, is draining the tank. But that will be a problem no matter what. If you have a drain in the room/closet where your heater is located, you might have to sacrifice a garden hose (into a 2-3 foot section) to drain the tank. I did it on Thanksgiving day a few years ago. Cost maybe <$50 if you include the hose.
My cousin in Arizona, where we visit in winter to see blue sky and sun, has a propane on-demand water heater . Her trick for showering is to turn on the hot water full blast, and once the heated water gets to the shower, add cold till it’s comfortable.
The device is located between the washing machine and the kitchen sink, so it takes a few seconds to arrive at the shower. This gives the on-demand unit enough waterflow to kick things off. Once in a great while the flow through the on-demand heater drops enough to trip the shut-off, and you lose hot water for 45 seconds or so, as mentioned above, but it saves SO MUCH energy, to me it’s great.
Something to keep an eye on
The “replace-Obama-with-Bayh” meme continues. Now, Doug Schoen of Mark-Penn-consulting-firm fame advises Obama not to run for re-election.
Don’t get the Bosch! I got one and cold nights or a fire on non cold nights would cause the element to freeze due to backflow, I was able to fix it after bursting the element six times before we had some really cold weather and it burst beyond repair.
I believe the rinnai has some electric/computer controls that will fire the burner if the element gets too cold.
the bosch is totally mechanical ie dumb.
I now have got some super efficient plastic electric tank heater, I think it was half price with subsidies from the electric company.
Got a new gas water heater last spring, energy star rated & pretty efficient. I seriously considered the on demand heater but I read a lot or reviews that said while it saved gas, it used more water because of having to run the water for a long time before it would heat up, they had to remove flow restrictors on the faucets, etc.
Anyway, the new gas heater is a lot more efficient than my old one and, where I live, it’s more economical to use gas than electricity even though enormous amounts of electricity are generated here (and sold elsewhere, I guess) and we don’t get enough sun for reliable solar.
We have had a Rennai propane powered heater for 3 years. As others have noted there are quirks that you learn to live with.
Hot water doesn’t arrive right away. The distance from the faucet to the tank can make a difference. Sequencing the usage can make a difference: turn on the hot water faucet, brush your teeth while the water is cold, shave as it warms up, and then jump in the shower when it is hot. Then you will have hot water forever.
Getting hot water for some short task will waste a lot of water before it warms up. On the other hand you are not paying to continually heat water that you won’t use. There are trade offs. Even storage tank systems will have to push a lot of cold water before the hot water arrives though. Recirculating systems can solve this problem but then you are paying for power to move the water.
Some add a small storage tank that keeps the water hot near the point of use. Or maybe an electric hot water spigot at your kitchen sink. Retrofitting all of these might be a problem. Ours was new construction.
Fine Homebuilding magazine has had some good articles and discussions on the pros and cons of these systems.
We have adapted. We learned to wash some dishes in the kitchen sink after we started the dishwasher or the clothes washer to minimize water waste. We have a well. We like to conserve the water.
I’d consider solar next time.
I researched this when ours died and decided that the additional cost did not pay out for on demand, it was the same tank vs. tankless if both lasted the expected lifespan. I called a good plumber and he installed what he knows is reliable and it was much cheaper than I expected. And, it keeps the water hot for a week, even if you turn it down when you leave town, so it really is efficient, even if it’s storing hot water all the time.
I must really love you because I got off my ass and went down to check the brand. It’s an AO Smith Promax and it’s cold to the touch, even full of piping hot water. No problems in the 2 or so years we’ve had it. It just does its thing.
I have a Rinnai and absolutely love it. My gas bill has gone way down since I installed it. However, if you have a tankless water heater you will never again wash your hands in warm water at the bathroom sink.
President Lincoln didn’t have no hot water heater, and look what he accomplished. whiner.
When my tank blew, I installed a tankless unit myself. I had never done plumbing before, I bought a book on it from Home Depot and was patient with myself. Turns out that doing copper pipe isn’t that hard, really.
It took a couple of days, which sucked, but hey, it saved me a bunch of money. The heater was $1,000, installed it would have been $2,000 or more.
My gas bills went down an astounding amount…from $40 a month to $15 (both summertime bills, only gas on in the house was the water heater–we have an electric stove).
Only problem with it is that it does take a few more seconds to get the water hot at the taps in the house now. I wish I had installed it on the other side of the basement, so it would have been right next to all of the taps in the house…that would have required running a gas line 10 more feet. I might still move it someday…
I’ve always said running a blog is a tankless task.
Definitely get a plumber to make a recommendation. What I heard-said was that on-demand systems are great when the prevailing temperature is high enough, but you might want a storage-style if your prevailing temps get cold enough. True? False? I dunno.
But I do know this: you *need* to be sure you know your capacity. If you need n gallons per minute, and you only ask for n/2 gallons per minute, ain’t *nobody* happy.
Also, remember, you don’t just want the capacity for *you*… you want the capacity for the future (or for the next buyer).
there isn’t a faucet in our house that doesn’t take ~2min in the AM to get hot water.
my morning rituals all revolve around waiting for the hot water to make the 15′ journeys from the HW heater to the sinks.
it’s only REALLY hot in the winter.
i have no idea what kind of heater we have.
John McCain didn’t get much hot water heater at the Hanoi Hilton.
Consider where in your dwelling the heater is/will be located. A storage (tank) heater in unconditioned (unheated) space just loses heat to atmosphere, whereas the standby loss of a storage heater inside the heated envelope of the house means the furnace or boiler works a little less hard in winter, and the AC works a little harder in summer. Figure out what your cost per million BTUs is with electric, 4314 btu/kwh if memory serves, vs street gas or propane. Electric is 100% efficient, and gas/LP appliances have efficiencies that vary.
Tankless heaters are great, and the gas/LP ones are markedly more efficient long-term than equivalent storage type heaters, but the tankless (demand) units do require regular maintenance, which could add to their overall cost. As mentioned, water quality must be considered.
Gas/LP heaters that do not require a connection to house current will still work in a power outage, so long as water pressure is present. If you have a well pump, you’ve got no water when the grid is down, so no real advantage on that front. City water will usually work.
Combustion appliances like gas water heaters need air, and if that air is drawn from inside the house, you may need make-up air, or the heater can backdraft a fireplace or woodstove. This is usually only a problem in modern, tightly sealed houses. Newer style heaters draw their combustion air from outside, so no problem.
A knowledgeable, trustworthy person would be very helpful in this effort.
I’ve had tankless for a long time. My current one is a Noritz and is excellent. Good low flow activation, remote thermostat. A little pricey. Hot water comes thru no different than a tank heater and never runs out.
Here in Rick Scott’s Florida, infrastructure is for
nancy-boy Crist moderates candy-assessocia1ists. Which is to say, don’t count on your gas supply.
When my original water heater gave up the ghost after 25 years, I went with a solar panel plumbed into a new conventional electric water heater. For a single person like yrs. trly., one panel gives me plenty. When I finally get on the stick about my bathroom upgrade projects, I’m going to install a recirculating pump on a timer for instant hot water whenever I’m home.
Size matters! I can’t recommend any brand or type, but capacity….don’t go with anything less than a 50 gallon amount.
A recent Consumer Reports said on-demand heaters for normal household use don’t save any money, gas or electric. If you’ve got plenty of money, they recommended one of the new heat pump electric water heaters, which will pay for themselves eventually, but they’re really expensive. We’ve got a plain old 50 gallon gas water heater, AO Smith’s extra-insulated model, and it’s worked just fine for the last 10 years, and is fairly efficient, too.
My three (3) Pets of Balloon Juice calendars arrived today!! One for me, two for Christmas gifts.
The calendar is wonderful. I think I recognise a few familiar furries (talkin to you, Lady Smudge), and this is in no way a criticism but a humble suggestion for next year: is there any way the designers could include a legend of which pet belongs to whom, name of animal, nym of BJ-er? I’m not looking for biographies or the full panoply of rescue stories, just a quick-and-dirty identifier (e.g. “#7, Tunch, John Cole” or “#19, Charlie, General Stuck.”)
But while I’m on this roll: if you’ve been in a bookstore lately, you know that there are dozens of dog and cat (and parrot and rabbit and horse) books on the tables, many of them solid dependable sellers. Has anyone ever thought (talkin to you, Anne Laurie) of compiling the most interesting/moving/unusual rescue stories and putting together a book? Basically an aggregation of the early morning pet rescue stories we all love anyhow, with photos. I think we have a good core readership right here, and most of the stories have wide appeal for a bigger audience. Think about it, of course with proceeds again going to Charlie’s Angels or another worthy cause.
On demand, hands down. I’ve had both, and love my little tiny heater (it hangs on the wall, taking up little space in the basement). Endless hot water, if you’re so inclined.
I have the same model my plumber installed for himself, and for others in his family.
And there is the matter of tax deductibility (somewhere around 30% IIRC).
Don’t know if I’ll save much in the long run, but even if I only break even I’m thrilled.
I took a class on green building/home construction a year ago. As part of the class we got to tour a home under renovation. The city also had a “green week” and as part of it they hosted a “green tour” of the city focused on solar.
What I learned about water heaters is:
1. Tankless are more efficient than the usual old-style water heaters.
2. The contractor who ran the course said that clients seemed to have more problems with the gas ones heating the water to the proper temperature than the electric ones. But that was hearsay, so he wasn’t offering as his personal opinion.
3. A solar water heater is one of the best ways to incorporate solar into your house. But you still need some water heater as a backup because even in the sunniest locations, not all days are sunny.
If you go tankless gas is usually cheaper. Consumer Reports did a comparison within the last few months of various options, including some discussion of tankless, solar and what they called hybrid water heaters. These last heaters use a heat pump supplemented by another element when needed and cost a good bit, but the payback period was not crazy. I believe it was the October issue.
One thing they note is that you can get a 30% tax credit if you get the job done this year if you go with a model that is eligible for a tax credit due to its use of less electricity or gas. The article will have more details than I can remember, but it is behind a pay wall (that it probably worth paying to cross if you’re serious about a heater).
Bruce (formerly Steve S.)
When our water heater died about a year and a half ago I had our plumber quote both a traditional and on-demand replacement. Code required that on-demand have its own dedicated venting, so the labor was going to be three times the cost of the heater. I hope you don’t face a similar barrier.
Yes on the gas for deman heaters, assuming you can. My SO and I moved into a condo in July. The shower/bathtub has an electric demand heater. Looking at a daily graph of our power consumption, I can spot when one of us is out of town, and the times when more than two showers per day happen. (Abstractly, I suppose we could be that interesting, but no.)
But the point is, I see the baseline use, and the added light/computer use for another body is absolutely nothing compared to another shower. It would probably be a little lower if we had back to back shower-time schedules, or were frisky that way while being quick.
Maybe this wouldn’t bother others, but I dislike a household feature that makes me think about the cost/benefit of destinking myself, when I can really do the math in my head. Mainly, because, well, how do you put a price on stinky?
On demand won’t necessarily save money (as RAM noted) but will save energy and reduce your carbon footprint especially if you are in an area where electricity comes from coal. In LA we can (and we do) pay a premium for a “green mix” of electricity (and even then, it is pretty cheap relatively).
I would say the key issue is making sure that (especially if you have low flow faucets) the minimum flow rate to start the heater is below the hot water flow at the various points of demand around the house. With some of these newer scald protection faucets, there can be hot/cold flow shifting that can confuse the water heater. It isn’t bad for the heater but can result in one annoyingly adjusting the faucets up and down all the time. Getting input from a plumber with a lot of experience with tankless is a good idea.
All gas water heaters need sufficient air intake and exhaust but because the instant heating happens as water flows quickly through the pipes, the flame grid at the heat exchanger has to be pretty big. This means the gas intake, air intake, and exhaust all have to be bigger than for a tank. Depending on your installation situation, each of these items can add $$$ to switching over. If you have a gas fireplace or gas furnace, you probably won’t need to upgrade the gas meter but that’s a possible worst case scenario where you actually need larger pipes to be run.
We have lived fairly well with an older model tankless but there are times when I might need to fine tune water temp by opening up another faucet to hit sufficient flow. I plan to replace with a new more sensitive model this year.
I have had to do minor maintenance on the tankless (it is about 15 years old at this point ) but these things are pretty simple ultimately (not much different from a tank heater). Many of the current high end tank heaters aren’t easily serviceable by DIYers.
Go Energy Star rated for sure…the savings really are there. My furnace is paying for itself in three years. I live in an area with hard water, so I rent…but if your water is soft enough, buy. Remember, yearly maintenance is a must.
I have installed a number of gas fired on-demand water heaters. (I’m a licensed contractor for over 25 years) They are much more efficient than tank heaters, although there is some lag time in getting hot water, you never heat water you don’t use.
The Rinnais are very efficient and reliable units. They install inside the house (although they do make an outside unit) so there is no problem with freezing. Most all tankless heaters use a power vent to vent exhaust and must be vented through a wall to the outside; however, any gas water heater must be vented, tankless or not. Venting form a basement location can be a logistical problem; if so, your plumber should be able to tell you after a cursory examination.
The Rinnais and Noritz units use a minimal amount of electricity for ignition and the power vent. I haven’t installed one, but I understand that the Bosch units generate the necessary electricity from the water flow.
Rinnai recommends that for maximum efficiency, the tankless units be set to the comfortable temperature setting and the hot water be used without mixing with cold. They have eletronic remote thermostats, so that the water temperature can be adjusted at the point of use, and even from multiple points of use if you wish, but I have never found this necessary. It mainly seems to be a luxury feature to impress people in high-end residences. As to sizing, the most populsr units are 2.5 bathroom units. I’ve had one in my house for the past 5 years, with my wife and two teenage sons showering each morning and have never lacked for hot water. Maybe if we hd both showers, the kitchen sink, washing machine and dishwasher all going at the same time it would be a problem, but we’ve never experienced that.
The best feature is that the four of us can all shower in the morning and never run out of hot water. With our old 50 gallon tank, that was always a problem.
We have a Rinnai on demand gas H2O heater in Seattle. Awesome, no complaints
We tried an electric one and it never got the water hot enough to fill up a bathtub. I’ve heard the gas ones work better, but keep your receipt.
I have master’s degrees in architecture and building science, FWIW. And if you can install a PV panel facing south, preferably on an incline, I’d recommend going solar all the way. Arizona has a number of rebates that are expiring at the end of the year, and I believe quite a few other states do, too, so I would definitely investigate that. (I want one on my house, but it’s gonna be a bitch and a half because our utility room is about three feet below grade, and our roof is tile. Argh.) If you have gas as an option, I’d choose that over electric, ’cause electricity is expected to climb in price in the next few years. Lots of local municipalities and utilities have rebates for high-efficiency appliances—investigate that, as well.
Also, There was a $300 federal tax credit for converting to those Rinnais a few years ago, but I’m not sure if it’s still out there. The dealer should be able to tell you.
Seconded. Make it volutary and allow people to choose when they submit their photos if they want to be identified or not.
Definitely go with the tankless gas water heater. I grew up with them in Europe and I wish I had one now.
Why on earth would anybody want to waste all that energy to keep a tank of water hot all day?
The claim that the hot water doesn’t arrive right away has more to do with how far the heater is from your shower than the type of heater you use.
A good flow through heater can provide close to 5 gallon per minute of hot water with 55 Fahrenheit rise.
One last thing. Go with the bigger one. I’d say get a unit that can supply water for at least 2 simultaneous showers. It might cost a bit more, but when later you need hot water for more than one person, you do not need to change the unit.
@ John Cole
We did a home addition and since it’s separated from the main house it needed separate HVAC and hot water. For space considerations we went tankless with a Noritz gas water heater. It has been flawless–providing endless hot showers but using no energy whatever when idle (that bathroom is used infrequently). It’s also about the size of a toaster oven so takes very little space.
On the downside it was more expensive than a traditional tank heater, probably 4x as much. The damn stainless flu pipe and chimney were expensive as well, but would probably have been required for a traditional gas heater too. I’d be interested in converting the rest of the house to tankless, but have been advised we didn’t have the needed gas flow capacity. Who’da thunk?
If you’re converting to gas from electrical, budget for adding the venting. That was a big part of the system cost for our addition.
I’m confused. I had the impression that you were a renter.
So why are you replacing your own water heater? Or you just want to recommend one to your landlord?
Maybe I’m overthinking this, yes?
If you got to junk the old water heater and are bored for a diy project, you can always build “a flat-out good-looking stove“…
One of the surprises learned living in the water-challenged West is that dishwashers use much less water than hand washing.
This article says a German study said dishwashers use half the energy and 1/6 the water. http://www.treehugger.com/files/2005/08/dishwasher_vs_h.php
A few years ago when I was updating the systems in our house, this was the reason the HVAC guy recommended NOT going on-demand. He looked in the other room at my two daughters and told me the extra money for on-demand and it’s return-on-efficiency advantages would be undone by the unlimited usage capabilities of teenage daughters.
Shouldn’t be a problem anytime for John, so I’d go for it.
As for gas vs. electric tanks, I’ve had both in the last few years, and I’d go gas for sure.
Why wait? Working with black iron pipe for gas lines is even easier than copper water lines.
Since this is an open thread I thought I’d share this great post from a Rand Paul fan about how he’s got an incurable painful disease and no insurance and suddenly is re-thinking his libertarian stance on health insurance.
The comments are priceless.
If a conservative is supposed to be a liberal who’s been mugged, then a libertarian is a dumbass who’s never faced real adversity.
I ran the tankless question by my home inspector when I moved over the summer. My family has known the guy a long time, he’s a local builder, and he’s not a bullshitter. His opinion was that the current gas tanks are so efficient that they’ve overtaken the tankless heaters in avoiding gas usage. Tie in how tankless is more expensive in most cases and you’re paying more now and later. He would only recommend tankless if you have a lot of people in a home (say, three or more teenagers and two adults) and you need more hot water in the morning than you’d find in the largest tanks.
I had a Bosch 125HX installed in my old house. It’s great not to have to worry about running out of hot water, but at least for that model (which they don’t make anymore) there were a few caveats:
The heaters are not really designed for a typical American house where the water heater lives in the basement, so it can take a pretty long time to warm up. If your water pressure isn’t great you may have trouble getting it to turn on from an upstairs tap unless you turn the heat all the way up on it.
If you have a model that generates its own spark to light the burners, this may not do you any good, because you might need a draft inducer to get it to vent properly (I did… expensive…), which uses mains power and won’t allow the unit to start up unless it can operate.
Don’t let it freeze! Mine froze a few times and sprung a leak, which requires you to buy a new heat exchanger (luckily I was able to get a used one for $200, but usually they are $500). If you need a draft inducer to get yours to vent, most likely there will also be a downdraft in the chimney, which means that on a cold night 10 degree air will be blowing directly on your heat exchanger. The solution is to turn the hot water on just a trickle, not enough to actually light the burners, on cold nights.
I could have avoided these problems by actually consulting with a plumber before buying mine – there are side-venting models which don’t have these problems, and I think the non-Bosch options are somewhat better too.
All in all it was still a good thing, because it saved a lot of space in the laundry room, and the endless hot water was really nice. But it definitely didn’t save me any money.
I moved into my 1976 Vermont hippie house in 2001, and found an on-demand water heater that was installed in 1985. I’m still using it. And the technology has gotten way better and more efficient since then. Bosch makes some pretty nifty ones – there’s all sorts of models out there that will satisfy whatever your usage is.
I’d say go for it. The extra cost will be more than offset by the reduced gas use and longevity.
I agree with the commenters who’ve said that you should consult a local plumber, but I’d like to add one other possibility: a regular tank water heater plus recirculation. A tiny pump is all that is necessary, and it should have a timer so you’re not recirculating and using energy all night.
In Santa Fe, where water isn’t as plentiful as it is in West Virginia, either recirculation or on-demand water heating is now required, to save water.
I’m not sure how much replumbing of your house would be necessary; seems like it should be possible to simply reconnect one end to the other, but your plumber will know.
An additional benefit is that now all the hot water pipes in your house become part of the hot water storage system. So they should be well-insulated, but they should be anyway.
@yoodow: everything he said, except if you have a big house with the bathrooms far apart you might want to go with two or three smaller units located closer to the points of use, for efficiency and to get that water hot sooner at the spigot.
@Mr. Furious: leaking or undersized water lines won’t asphyxiate everyone in your house, though. better get some training before you start fooling with gas lines too much.
Tankless gas water heat requires at MINIMUM a 3/4″ gas line. Do you have that?
My plumber, who I know almost 30 years insisted this autumn that I buy a Bradford (Merkin built) and I know he wasn’t getting a kickback, because he made sure I bought it myself. He said with Bosch and other popular brands, he would probably be back doing the job over again in 5 or so years. Ditto on the efficiency–probably as good or better than tankless.