I don’t get why there is even still a market for tank-based water heaters. On-demand heaters use less energy, take up almost no space, are less expensive and never run out. Why on earth would someone who needs a new water heater buy the tank kind?
Because they do run out. I’ve experienced it in a tiny 2BR house. If you are doing dishes, no showering. If you are doing laundry, no showering. Now that I have a family of three, I imagine it would be huge hassle.
Unless they’ve improve dramatically in the last seven years.
Consumer Reports said it could take up to 22 years to break even on the higher initial costs versus a tank system. Although that’s from 2008 so maybe they’re better now.
The Department of Energy also agrees with the higher upfront costs and gives the well-qualified statement that “tankless water heaters will typically last longer and have lower operating and energy costs, which could offset its higher purchase price” (bolding mine). In other words, depending on your situation it might eventually turn a savings for you but it’s not guaranteed and it won’t be immediate.
If you’re looking at even a ten year gap before you see a savings (and I’m just making up that ten year number) then it’s very likely people would opt for the initially cheaper option since they might figure they won’t even live there in ten years or won’t save enough in the intervening years to worry about it.
I don’t know much about them, but I found this (which is dated May 2, 2012):
(On preview, looks like Jophiel ninja’d me to this link!)
It mentions the problem TheMightyAtlas brought up
I’m also a bit skeptical about the ability of an on-demand heater to heat enough cold water to a high enough temperature to take a comfortable shower in the winter, but that may just be my unfamiliarity with the technology.
We had to replace our water heater five or six years ago. At that time, even the least-expensive tankless heater was at least twice the price of the good-sized tank heater we wound up purchasing.
Yes, I’m smart enough to realize that the tankless heater is more efficient, and will cost less to operate. No, I guess I’m not willing to pony up another $300 for those future savings.
Some of us still have 60 amp electric services (instead of the modern 200 amp or 400 amp services). If you have a 60 amp service you will need to upgrade to a higher level (which costs a few thousand dollars)–if you are talking about an electric hot water heater.
Why would they be any worse than a tank? They have a far superior heat transfer system almost by definition. They are designed for the task; they do fine as long as you pick a model with the right capacity. They work great in the winter.
There is absolutely no problem with that, if only one shower is going at a time (for gas models, anyway). And you can have multiple serial showerers all day long and not run out. Because it’s a big flame and the heating area is also large.
The big flame does lead to another issue with installing these, which is the venting. Due to the larger amount of combustion products, these often have to be vented directly to the outside, rather than through an existing chimney (I don’t really understand this, but so I have been told). This adds to the installation cost, at least for the first one. Also, again I think due to the higher gas usage, mine has to be inspected each year, which costs $70 or so, I think.
Roddy
Exactly. The only drawback to a tankless is that quite often they need a dedicated gas line from the meter, which is an expensive installation. Also, there is the labor for the new tank installation, etc. With a tank heater, it’s just a swap-out. The tankless heater itself is not all that expensive, however.
Correct me if I’m wrong, but shouldn’t the physics of it mean a gas tankless water heater uses more energy per unit of water heated, because it has to do it faster ? That is why newer high efficiency gas furnace heats the air to a lower temperature and runs longer, right ? The tankless only has a chance to win because you leave the hot water in the tank sit and cool off/reheat once heated. Edit to say, by which I mean that if you did say 40 gallons tankless vs 40 gallons tank heating up one time. Obviously the tankless will win overall if both are on 24 hours a day and there is lots of time sitting unused.
In any case when I looked at it the extra initial cost would basically never pay off in my usage scenario - because the initial costs include running a new gas line, and a bigger exit pipe/chimney.
Why I don’t have one.
- Connecting to a local gas system would cost a couple thou.
- see 1 above.
- If all you’ve got is electric, then you get a tank.
Because it is also the water source for the water circulating baseboard heaters that keep us mostly from freezing in the winter. [we leave the thermostat set at 40F and generally heat with the wood stove.]
If your power goes out you have no hot water.
We lived in a rental and the thing was constantly clogging up with residue.
Our landlord would flush it out and then we would literally have rocks coming out in the tub. Then a few months later it would stop working, he would flush it and repeat.
We have a tankless water heater that’s fired by our oil burner. The learning curve might seem boggling to some, but once you get used to it, it’s much more economical than a stand-alone heater.
It’s true that doing more than one hot-water activity at the same time will tax it. That was the first thing we were told. We were also told to minimize the hot water as much as possible to keep the oil burner from continuously firing (think Navy showers, for example).
There’s only two of us in our household, btw.
The easy answer to your OP is that you’re mistaken on half of the points you raise in favor of tankless. The units are not less expensive and the capacity is limited. Smaller/average-sized units are not good choices for families that may have 2 showers going at the same time before work or school.
I looked in to replacing my hot water heater. By the time I installed the dedicated electric lines (I don’t have gas), and installed the heaters, the total cost approached $1400. I replaced my tank with a larger model for about $350. The extra capacity means I never run out.
Tankless do not cost less at least here in Chicago. I sell 40 gal gas heaters (Bradford and White) for about $430. Eternal brand tankless are around $1800 and are much more difficult to install.
Yeah, that’s why you size it appropriately. Like you do for an AC. Or a washing machine.
Yeah. But I think what they’re saying is that once you do that, the unit requires upgrades to the gas or electrical lines which makes the changeover prohibitively expensive.
Fascinating. Especially about the dedicated vent, I would never have thought of that.
Somebody here once mentioned having a combined furnace/ac/water heater which captured the heat the A/C removed to heat the water. Anybody know what terms I’d use to google that?
Tank heaters have several advantages. They’re cheaper up front, and might be cheaper in the long run too. Converting from tank to tankless usually involves some gas line work, which is rarely cheap. Tanks aren’t as much less efficient as they used to be, since they’re so well insulated, and heat transfer is more efficient.
With a tank, the hot water starts faster (by a few seconds), and you don’t generally get “cold water sandwich”. I had to modify my dishwashing style to deal with the CWS, which is a bit of a nuisance, even though my Rinnai top-of-the-line tankless has logic to help avoid it. (A complicating factor is a long distance between kitchen and heater, and I plan to put a smaller electric unit in the kitchen, which will minimize the issue.)
Tankless can provide any quantity of flow, if you get a big enough unit and/or enough of them ganged together, but that can run some serious bucks.
You have to do the math, or let the online widget do the math. You plug in the winter groundwater temperature (50 degrees for us here in NC), the desired temp (120 degrees, for me), and the number and types of facilities to get simultaneous service, and it tells you basically how many BTUs you need, which dictates which model you need and how many.
Tip: don’t plug in all your facilities expecting they’ll all be in use at the same time unless that’s what you really want to handle. My house has three showers, laundry, and kitchen, but I only got enough to handle two showers and either laundry or kitchen at the same time. Frankly, you’d need a pretty big tank to handle all 5 at the same time anyway, unless people take Navy showers.
Where a tankless is a clear winner is a home that’s frequently unoccupied for a day or more. No point in keeping water hot if nobody’s there. Another benefit is that you can have multiple water heaters closer to the sources (generally, electric ones for smaller loads like kitchen/laundry).
My guess is that the best solution in terms of the best service, fewest drawbacks, and best energy economy are the hybrid ones, with small tanks. That provides the instantly available hot water and avoids cold-water-sandwich, but without the expense of keeping a big tank of water hot all the time. Plus a small tank can be very well insulated.