Brain Trust question....tankless water heaters

Dani

Dani

Well-known member
Supporter
Hey y'all....I am looking at the possibility of getting rid of my old water heater and getting a tankless water heater. It will be electric, not gas. I am in the research phase so maybe y'all can help me out.

Has anyone done the tankless? Pros? Cons? Any brand/model recommendations? My house is under 1000 sq ft if it matters on brand or model recommendation.

Thanks a ton in advance,

Dani
 
Our house came with a tankless heater installed in our crawlspace. Our water heater is gas fired. We just had to replace it after owning the house for 5 years as it was not cleaned regularly.

If you don't have a water treatment system to remove dissolved lime, you will need to do annual maintenance or have a service contract to maintain the unit.

There is a maintenance cost that comes with the tankless that usually does not happen with water heaters.

Rick
 
Dani

Tankless electric water heaters have a HUGE current draw. I think the one for the small space over my shop was going to require over 100 amps. Your electrical panel may not have enough room for the circuit needed and you will be looking at adding a sub-panel. Regardless, you will have to run some very heavy gauge wire and it is expensive for both material and labor. I ended up going with a tank heater. A lot less expensive. Gas tankless make a lot of sense, but I can't see too many scenarios where an electric does. Maybe a new build but that's about it.
 
Eric Patterson said:
Dani

Tankless electric water heaters have a HUGE current draw. I think the one for the small space over my shop was going to require over 100 amps. Your electrical panel may not have enough room for the circuit needed and you will be looking at adding a sub-panel. Regardless, you will have to run some very heavy gauge wire and it is expensive for both material and labor. I ended up going with a tank heater. A lot less expensive. Gas tankless make a lot of sense, but I can't see too many scenarios where an electric does. Maybe a new build but that's about it.
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Essentially this. I have all electric as well. I have a 100 amp sub panel that I put in that we could easily put the tankless on, but it pulls so much electricity from my research, that I bagged the idea and going to go with a 50 gal electric water heater. Its on the list of things to do in the next couple months. Mine works fine, just 28 years old and I know it has sand in it at this point since we are on a well.
 
Have had a gas tankless for about a year now. I wouldn't do it again. For some things its great, other things it kind of sucks.

Pros: For a long hot shower at a consistent temperature it is awesome. Set it and forget it.
Even the gas version is very quiet. It probably saves on energy costs but with gas it isn't as noticeable as it might be with electric.

Cons: If you want it to work the best you need a recirculating pump and probably a small tank...yes, a tank on a tankless heater. The cold sandwich they gloss over is very real and it sucks. No way does it save on water with having to run it until you get hot water. It really sucks when the dishwasher is running. The small amounts it takes doesn't run it enough to get past the cold and luke warm water. This just keeps sending in cold water into the system. Even a small tank won't ever let truly hot water get to it. Same way doing dishes by hand, I have to keep it running a little all the time so it doesn't get cold water back in the loop.

I wouldn't do it again. In a small enough house it may work better. In a cabin it would likely be great. Also figure in all the add-ons because they are not optional.
My $.02
 
We have had Rinnai tankless gas hot water heaters for over 15 years and would never go back to a normal tank heater.
Rinnai is a Japanese brand, tankless is all that is used in Japan and has been for well over 20 years.
Endless hot water even with two showers, the dishwasher and a sink running is nice.
And you can easily adjust the temperature with the digital controls.
That said, they are a little quirky, mainly, as noted above, that they don't work at low flow.
And if you have hard water (as most of us do in Florida), you will need to flush it with full strength vinegar at least once a year to clean out the scale.

As Eric also noted above, electric ones are another story. I've heard they will expensive to operate. Its debatable if you will see any cost savings on your electric bill, it may even go up.
 
Carl said:
We have had Rinnai tankless gas hot water heaters for over 15 years and would never go back to a normal tank heater.
Rinnai is a Japanese brand, tankless is all that is used in Japan and has been for well over 20 years.
Endless hot water even with two showers, the dishwasher and a sink running is nice.
And you can easily adjust the temperature with the digital controls.
That said, they are a little quirky, mainly, as noted above, that they don't work at low flow.
And if you have hard water (as most of us do in Florida), you will need to flush it with full strength vinegar at least once a year to clean out the scale.

As Eric also noted above, electric ones are another story. I've heard they will expensive to operate. Its debatable if you will see any cost savings on your electric bill, it may even go up.
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This is what I found as well with my research.
 
Another option is a heat pump water heater. https://www.energy.gov/energysaver/heat-pump-water-heaters No idea if these are well adapted to the south, but heat pumps for home heating, cooling, and hot water are on a surge here in the northeast. Several frriends have gone with heat pumps for home heating and give rave reviews--and they work as air conditioning in the summer, which is hard to do with a boiler or furnace! I have not heard any feedback on the water heaters.
 
I have one, but it is gas fired. I also do not have the water issues noted above in my water supply, and I do no maintenance on it. I have had it 7 years, I love it, but were I faced with the choice you have with the current draw and mineral content in your water, I would not do it. One thing I can tell you, is that while it is great and gives me endless hot water, it doesn't save much of anything, maybe a few bucks a month on my gas bill since I went from a tank water heater to a tankless. And I mean $2-3 a month. I was amazed at how little gas I used with the hot water tank style water heater when I was able to compare. I actually did it because I wanted the extra space in the closet that it is in and I (obviously) have gas service. I think you have great advice above.
 
In Massachusetts they give you $750 towards a heat pump electric hot water. Energy use on a standard electric 50 gallon tank is ~$400 a year vs ~$100 a year for the heat pump. Works better down south as they are less efficient pulling in and warming cold air. Also, your basement usually gets a bit colder as it pulls in warm air and spits out cold air. You can duct the input and output to make them more efficient or if your tank is in a confined space. I think folks in Maine etc have been surprised by the electricity use in cold regions like maine where they are less efficient for hearing.I added a heat pump to my propane ducted furnace as mass (really the electric company) has a $10k rebate for heat pumps for heating, but I have a wood stove so just use it in the shoulder seasons when I'm less motivated to burn wood. I tried this one calculator where you put in the efficiency of the units (electric and propane) and the cost of each and it tells you which temp to switch to propane fuel on your dual heat thermostat. For me, it told me the electric was always cheaper no matter the temps, but I'm a little skeptical.
 
TimJ said:
Have had a gas tankless for about a year now. I wouldn't do it again. For some things its great, other things it kind of sucks.

Pros: For a long hot shower at a consistent temperature it is awesome. Set it and forget it.
Even the gas version is very quiet. It probably saves on energy costs but with gas it isn't as noticeable as it might be with electric.

Cons: If you want it to work the best you need a recirculating pump and probably a small tank...yes, a tank on a tankless heater. The cold sandwich they gloss over is very real and it sucks. No way does it save on water with having to run it until you get hot water. It really sucks when the dishwasher is running. The small amounts it takes doesn't run it enough to get past the cold and luke warm water. This just keeps sending in cold water into the system. Even a small tank won't ever let truly hot water get to it. Same way doing dishes by hand, I have to keep it running a little all the time so it doesn't get cold water back in the loop.

I wouldn't do it again. In a small enough house it may work better. In a cabin it would likely be great. Also figure in all the add-ons because they are not optional.
My $.02
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Tim,

I forgot to mention the wait for hot water. There is a lag before the hot water comes out usually a minute or two when turning on the tap.

Rick Lathrop
 
I put in a propane Rinnai 3 years ago. I descale it annually. It is great but you do have to wait for the water to get heated and to your faucet. I like it but I might have installed a loop system in a new build. I have a well so not too concerned with wasting water but you do have to wait. Holding 40 gallons of hot water in a tank isn't too efficient and the tank takes up a bunch of space. So when I remodeled the laundry room I gained pantry space that had been a closet for the hot water heater. I just put the tankless system on the wall above a counter. I've seen some applications with the tankless system on the outside of the house.
 
There is some merit to the gas tankless water heaters but electric is a no go. I’m not a plumber, I’m an electrician and we have run wire for new tankless water heater set ups (usually 2 paralleled 40 amp 240 volt circuits) then a few months later gone back a few months later to rewire the set up for a standard tanked water heater due to the extremely high electric bills
 
I don’t see any more latent time to get hot water at the tap with the tankless vs tank.

Ours have both been on the outside of the house. But we don’t get many hard freezes.

Saving space/gaining a new closet was one reason we did the conversions.
Getting the gas appliances out of the house back in Mobile was another reason.
 
A house I rented had a propane on demand heater that was wonderful when it worked, but the pilot light was prone to going out and leaving us cold showers. Fine if you check the pilot before turning on the tap . . . . . .
 
Interesting, I dont think any of the new ones have pilot lights, all electronic ignition.
 
They need cleaned and serviced VERY regularly. Scale can build up quickly (in like 2 years) and it can get into other appliances and ruin them. Friend just lost her washer that is plugged with scale from tankless heater.
 
Regarding extremely high electric bills...wouldn't that be more a factor of how much hot water someone actually uses? Or how many people are in the house that use hot water? I actually wasn't looking at the cost savings of an electric tankless heater but looking at it more as a way to gain storage space in the laundry room. Maybe have a pantry. I remember reading in the past that gas is better than electric as far as tankless water heaters but I do not have gas hookup available and I don't want a tank just for a water heater.

The information about the de-scaling is good to know. I do have really hard well water so that is a consideration for me.

I am really appreciating the input. This is giving me lots to consider.
 
Dani said:
Regarding extremely high electric bills...wouldn't that be more a factor of how much hot water someone actually uses? Or how many people are in the house that use hot water? I actually wasn't looking at the cost savings of an electric tankless heater but looking at it more as a way to gain storage space in the laundry room. Maybe have a pantry. I remember reading in the past that gas is better than electric as far as tankless water heaters but I do not have gas hookup available and I don't want a tank just for a water heater.

The information about the de-scaling is good to know. I do have really hard well water so that is a consideration for me.

I am really appreciating the input. This is giving me lots to consider.
Click to expand...
Of course usage will play a factor in electric cost but it will still be cheaper to operate a standard water heater over tankless. You also need to consider the large cost of install for the new electric
 
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