DIY Home Improvement Forum banner

Tankless water heater vs. electrical water heater?

6K views 19 replies 10 participants last post by  YerDugliness 
#1 ·
I'm considering replacing my 55 gallon electric water heater. Though I won't do this myself but wanted to know what kind of savings I would see vs. going the conventional water heater style?

I've heard that using a "electric" tankless water heater was not as efficient as a conventional water heater but rather a gas tankless was the way to save. I don't have a choice as my area doesn't have gas. Now this was something I heard so I cannot confirm whether its true.

If someone has some information about this subject I'd love to hear about it.
 
#2 ·
I can't reply on an electric tankless, though I would imagine there could be a savings since the htr only heats water as it passes through it, where as a tank will cycle on & off all day just keeping water heated, in case someone needs it. I know the gas versions use less gas and save money. But either way because of the initial cost, it's a few years down the road before you 'break even'.
 
#3 ·
With electric tankless water heaters you have to take into account the installation cost. You will need at least 2 - 40 amp circuits installed for a whole house system. The last one I looked at required 3 - 40 amp circuits. Homeowners that do not have at least a 200 amp service panel will require the upgrade to 200 amp in most cases, or the addition of a sub panel.. These TWH's are power hogs to say the least. It is true that they only use power when hot water is needed, but if you look at the WHOLE picture, you will most likely never recoup the investment.
I did some research on TWH's and have decided I will never install one in my house. But I would install one in your house.

I do like the idea of using TWH's for point of service use. Like a small one under the kitchen sink for the sink and dishwasher. But not for the whole house.
 
#4 ·
I did some research on TWH's and have decided I will never install one in my house. But I would install one in your house.

would it be worth it on a new house?

There is also always special circumstances, like my dads office that has a shower, no one ever showers there, so it might be a waste to have a full hot water heater hot all the time. Or it would also be nice if you had a whole family that wanted to shower in the morning and not run out of water

But like me, if i had to replace mine, i might consider tankless, because i wouldn't be paying labor, and i get materials at a discount and some material free. Would i come out ahead over just replacing a conventional water heater?
 
#9 ·
Thanks for the information.

I just looked at my breaker panel and my current 55gallon electric water heater is using 2 - 30 amp breakers.

Now another thing is that my idea was that using/getting a tankless water heater was going to save us money some money. I know one problem that we have is that in the master bathroom it takes about 1 minute of running water for the shower to get warm/hot. That is definitely wasting a lot of water even though it's just my wife and I using it. I mean we are probably wasting about 7 gallons of water every shower just to get it warm enough to shower. I think the reason is that our master bathroom is so far away from out water heater.

I don't know if a tankless is out best option. I like the idea of having one because they seem to save water, and I would gain some space in my garage.
 
#12 · (Edited)
Thanks for the information.

I just looked at my breaker panel and my current 55gallon electric water heater is using 2 - 30 amp breakers.

I know one problem that we have is that in the master bathroom it takes about 1 minute of running water for the shower to get warm/hot. That is definitely wasting a lot of water even though it's just my wife and I using it. I mean we are probably wasting about 7 gallons of water every shower just to get it warm enough to shower.
It is possible to power an electric HWOD unit with two 40 amp 220V circuits, see here:

http://www.titanheater.com/proddetail.php?prod=Tempra-15

Other than that, the other units I notice in the same amperage range use one, single double pole 240V breaker, most of them using a 50 or 60 amp breaker. Since you have adequate space to string new wiring from the breaker panel, you might (again, remember, it all depends on your load usage calculations) be able to replace those two 30 amp circuits your current 55 gallon heater uses with one 60 amp circuit and new heavier gauge wiring and power something like this:

http://www.titanheater.com/proddetail.php?prod=SCR2-N100

or even this:

http://www.titanheater.com/proddetail.php?prod=SCR2-N120


As for the water waste, I did notice that it seemed to take longer for the water to get hot at the shower, but it might be that I just don't recall how long it took with the old gas-fired tanked heater--it was 4 years ago!! What I did was to order a special constant pressure/low flow shower head from the source I used for the HWOD unit. My HWOD unit requires a flow rate of 0.53 gallons per minute to activate, the shower head maintains the flow rate at 1.5 gallons per minute, and before I even pull that faucet on the shower I rotate it to provide pure hot water. I did also insulate the hot water pipes, seems to take only about 20 seconds now at 1.5 gpm, that's a loss of 0.5 gallons before it is up to full temperature. I usually stick a bucket under the tub faucet while I'm waiting for it to heat up and use the water for plants or rinse water at the kitchen sink (water is quite scarce where this vacation home is located, extreme SW KS, so I attempt to make use of almost all "waste water" in a creative manner).

Dugly :cool:
 
#10 ·
A retrofit in my area is not a good idea! For six months its necessary to heat our house.
Heat losses from the regular HW tank help with the heat load in the winter.
In summer, of course this heat loss must be removed by the air conditioner. Our cooling season is only about 2 months long, whereas we heat for six months.
The big advantage of tankless would be less water wastage. Our water is metered and we pay a sewer surcharge based on water consumption.
Perhaps on new construction or a major upgrade it could be justified, but not to replace an existing system. There would be no payback!
 
#14 ·
The smaller units that don't require much power may not be big enough for your application. These things have a tendency to cause a real annoying light flicker. The power company may need to install a larger transformer and secondary conductors as well.

I just looked at my breaker panel and my current 55gallon electric water heater is using 2 - 30 amp breakers.
Do the breakers have a tie bar connecting them? I'm thinking you are talking about one double pole breaker. (Single circuit)
I know one problem that we have is that in the master bathroom it takes about 1 minute of running water for the shower to get warm/hot. That is definitely wasting a lot of water even though it's just my wife and I using it. I mean we are probably wasting about 7 gallons of water every shower just to get it warm enough to shower. I think the reason is that our master bathroom is so far away from out water heater.
This is going to be a problem no matter what kind of water heater you have. In order to solve it, you may have to install a recirculating pump, or a larger dedicated line running directly to the bathroom.
I like the idea of having one because they seem to save water
Please explain this!

Some other threads regarding tankless electrics

http://www.diychatroom.com/showthread.php?t=23497
http://www.diychatroom.com/showthread.php?t=23153
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top