Water Heaters, Tank vs Tankless

[AP514]

Oh Also, had a friend use Electric tankless water. it keep blowing the CB all the time. Come to find out the plumbing for the heater came from below not from above...He had to reroute the plumbing to come down the wall (from attic) to the unit instead of up to the unit. not sure why but it fixed his problem....never popped the CB again. Also he said it was a power Hog....

 

[wyliesdiesels]

Thats a weird issue and i cant fathom why that would cause the breaker to trip.

 

[Bopbop]

I make my living as a Plumbing Engineer designing schools, hospitals, and all types of commercial buildings. My recommendation is not to use a tankless electric water heater. Use a tank type heater. Just to give you an idea a 4.5 KW tankless heater will give you a temperature rise of about 30 degrees F flowing 0.5 GPM.
In a home you will need 24 to 36 KW for a tankless heater. The problem with most larger tankless heaters is that the flow rate to turn on the elements is high enough that a lavatory faucet may not turn on the elements. There are some new tankless that claims to have the low flow issue fixed.
With the new energy requirements and tank insulation requirements there is not that much stand by heat loss.
Just to add if you can go with gas the gas heaters are really good.

 

[nsula_country]

Not everyone has access to NG or wants a LP tank in the yard...

One of the main reasons we chose tankless electric is the house plan did not really have very many places for a tank type heater without sacrificing closet space. The plans did not even have a tank area defined. Very open floor plan downstairs. Would have been in the attic upstairs... Negative Ghost Rider, Pattern Is Full... The tankless are on the wall in the laundry room and only protrude 4".

If you decide to go electric, I recommend this brand. I only recommend because I have 2 of them and they are trouble free for 6 years. We installed the ECO27 units.

https://www.ecosmartus.com/products/electric-tankless-water-heater

CT

 

[Bretny]

No place for a tank type heater. Where was it before they made tankless heaters?

 

[Radix2]

Update: Since this is new construction. Electrician says we should go with a 400 AMP Service ( Two 200 AMP service panels) for the home to be able to go with the tankless WH. This will cost us about $500 extra for us. We decided to go ahead and go this route.

The Tankless unit I will go with is an Eemax brand, model HA027240. with a max flow rate of 7GPM. and will require three 40 amp breakers.

Be careful with that max flow rate, it just means it will flow that, not doing much heating(<30 deg rise) at 60 psi.

I don't know your exact winter water inlet temp, but it's probably in the 50deg range, so for a hot shower at 110deg you need 60deg rise. For your unit, that means you have 3GPM.

Should be good with a single 2gpm showerhead, but if other faucets, dishwasher, washer kick on you may see the shower affected.

Also note that there is a recommended 3 or 4 gpm flow restrictor recommended when you install.

http://www.eemaxha.com/wp-content/uploads/2016/08/Spec-HomeAdvII.pdf

 

[Stuff]

There used to be utility rooms that you put the washer and dryer in as well. Sometimes in the corner of the garage. Now laundry is a fancy room and no one wants an ugly tank in it and the heating system goes in the attic.

Marble kitchen counter tops is what sells a house. Paying more for guaranteeing a hot shower is never even an option.

 

[nsula_country]

No place for a tank type heater. Where was it before they made tankless heaters?

LOL... Wife wanted larger closets!

Also used the area under the staircase for the air handler (downdraft). The other area under the staircase is the water closet in the Master Suite.

CT

 

[James-W]

There used to be utility rooms that you put the washer and dryer in as well. Sometimes in the corner of the garage. Now laundry is a fancy room and no one wants an ugly tank in it and the heating system goes in the attic.

Marble kitchen counter tops is what sells a house. Paying more for guaranteeing a hot shower is never even an option.

I agree wholeheartedly. Certain things sell a house and hot water is not usually something that would even come up when someone is looking for a house to buy. Having a laundry room on the main floor instead of in the basement or garage is getting to be a really big thing these days.

 

[AP514]

My big selling point if I would ever sell would be the Urnial No put the lip..put the lid down...No slash in the middle of the night......and me sleeping on the couch

 

[yeldogt]

With NG available -- only reason to go tankless is for the capacity. Modern tank units have very low standby loss ... A large HW tank unit can pump out a lot of hot water.

The electric tankless units pull lots of amps and often dim lights --

 

[Bretny]

There used to be utility rooms that you put the washer and dryer in as well. Sometimes in the corner of the garage. Now laundry is a fancy room and no one wants an ugly tank in it and the heating system goes in the attic.

Marble kitchen counter tops is what sells a house. Paying more for guaranteeing a hot shower is never even an option.

Hot water pay off on selling a house ranks right up there with a new septic. Some things new owners just expect to be there and work.

 

[nsula_country]

Hot water pay off on selling a house ranks right up there with a new septic. Some things new owners just expect to be there and work.

The ECO27 units were comparable to if not cheaper than 50 gal electric tank heaters. Plus are the size of a briefcase and wall mounted. Relatively 0% floor space loss.

With NG available -- only reason to go tankless is for the capacity. Modern tank units have very low standby loss ... A large HO tank unit can pump out a lot of hot water.

The electric units pull lots of amps and often dim lights --

Hence 400/320 service. Each ECO27 is on a 200 subpanel. No light dimming. The AC/HP's will "blink" lights on startup.

NG/LPG units require venting or external installation...

CT

 

[Denwood]

The most efficient way to heat hot water these days is a heat pump/tank unit. In your position, that's what I'd be looking at. The numbers are even better in warmer climates.

http://www.greenbuildingadvisor.com/blogs/dept/musings/heat-pump-water-heaters-come-age

We made the change to on demand (NG) and have not looked back. The only down side is a bit longer wait times for hot water upstairs. The other kicker with the on demand system is during power outages it does not operate. The old NG tank was an inefficient version with an open vent, however it did not need power to operate.

If you have a backup gen, no worries. Just mentioning the tank option as with a heat pump electric water heater, you'd have 60-80 gallons on tap during power outages.

 

[MFortie]

You misunderstood the function of a tankless water heater.

A tankless water heater CANNOT recirculate hot water through the house so you have instant hot water at every valve.

If you wanted that, then you need a recirculating pump and a hot water piping loop or a temp controlled flow valve at the furthest sink.

No. I didn't misunderstand the function of a tankless water heater. My comment was in comparison to the tank style it replaced. I had hot water much sooner when we had a tank. The tankless has a delayed start before the burner lights.

And yes, when it's winter and I'm standing under the cold water issuing from the shower head that comes out of our well tank while waiting for the hot water for 45 seconds, it's an issue! (Talk about shrinkage!) I have one of those corner shower enclosures with half round doors and have to be standing inside to start the shower lest I flood the floor by opening the doors.

I would think the recirc pump would 'cause the tankless to run all the time and defeat part of the purpose for having a tankless.

 

[walta]

Electric tank less water heaters use fewer kilowatts than than electric tank water heater because they have no standby losses. The water heating happen on demand so they use a lot of amps for the short amount of time you are running hot water, where the tank heater uses the same amount of energy heating the water it just does it over a longer period of time after your shower. So long as your utility does not have a demand charge the bills will be equal.

Let’s say your shower for 5 minutes at 2 gallon per minutes = 10 gallons of 30° water into the heater and 10 gallons out at 120°. So you heated 10 gallons with a 90° change in temp. Each gallon weighs 8.34 pounds X 10=83.4 pounds x 90° =7506 BTU. 1 BTU= 0.000293071 Kilowatt hours. 7506 X 0.000293071= 2.2 Kilowatt hours

The tankless heater adds 2.2 kWh to your bill over 5 minutes of time. The tank water heater adds the same 2.2 kWh to your bill over 30 minutes of time.

Walta

 

[Stuff]

You learn that running the hot in the sink is almost as good as running the shower for those 45 seconds.

A recirculating pump can be push button or motion activated.

 

[James-W]

Hot water pay off on selling a house ranks right up there with a new septic. Some things new owners just expect to be there and work.

If a country home has a new septic system, that certainly is a big plus because they are very expensive. But a water heater is a few hundred dollars and quite frankly, I doubt very few people, if anyone at all, would even inquire about the water heater. If they did inquire about the water heater, regardless of the condition of the water heater, I doubt it would be a deal breaker. Things like the roof and the foundation, those types of things can mean HUGE repair costs and they can be deal breakers.

As an example, I replaced our water heater with a 40 gallon power vent natural gas water heater. Cost a few hundred dollars and I did it in just a few hours. The reason it took that long was I had to drain the old one and that took awhile, then of course there was lunch and I had to revamp the water lines and the gas line. Anyway, point being, a water heater, in my opinion at least, doesn't have a big effect on whether or not a house sells. A new septic system, to my mind, would have a very big effect on whether or not a house sells.

 

[MFortie]

You learn that running the hot in the sink is almost as good as running the shower for those 45 seconds.

Yeah, I’ve done that before. Still hate running all that water down the drain, but, hey, it comes out of the ground (well) and I’m just putting it back (leach line)!

My better solution is let the wifey shower first - her bathroom is on the other side of mine ( we have “his” and ‘hers” bathrooms)!

 

[nsula_country]

The OP may have gotten the answers required by now. Maybe not...

I have an update on the EcoSmart tankless electric water heaters. As previously mentioned we installed two 27kw units in a parallel configuration. About a month ago I noticed one of them not working. Got busy and forgot about it. Figured it was toast. Been only using one since and temperature has been as low as 20's at night. No idea what ground water temp was.

This week started looking at threads and parts for them. Found out they have a control power fuse. It is a standard size (1/4" x 1 1/4") glass fuse, 3/16 amp (.187 amp). Opened unit up and found the fuse holder, blown fuse. Had some 1 amp fuses and viola! Workie again!

Some people claimed they had to replace fuses several times a year. Mostly due to power surges and such. Even for a control power fuse, (.187 amp AC) seems light... Have no problems using a 1 amp. These have been going since 2011 and this is the first fuse. Have 4 more as spares.

Just an FYI. They are very reliable, just require large capacity of current in use.

CT

 

[jvitez]

To reiterate: the best combination would be a tankless plus a tank-type heater. Two ways to do it.

1. Big tankless water heater, NG or electric, feeding a small electric water heater, small like 5 gal. Recirc pump keeps the hot water lines hot throughout the house, and that small amount of heat loss is made up by the 5 gal tank. When you turn on a faucet the tankless does the heavy lifting.

2. Standard size tank-type heater fed with a medium sized tankless. Can do a recirc system or not. A tank type heater can deliver about 70% of its volume before a significant water temperature drop. So a 60 gal tank has 42 gal of actual available hot water. If you feed this tank with a tankless, then the incoming water is hot so you have 100% of the tank capacity available for a "dump" load like filling a large tub or multiple hot water draws at the same time.

 

[yeldogt]

The most efficient way to heat hot water these days is a heat pump/tank unit. In your position, that's what I'd be looking at. The numbers are even better in warmer climates.

http://www.greenbuildingadvisor.com/blogs/dept/musings/heat-pump-water-heaters-come-age

We made the change to on demand (NG) and have not looked back. The only down side is a bit longer wait times for hot water upstairs. The other kicker with the on demand system is during power outages it does not operate. The old NG tank was an inefficient version with an open vent, however it did not need power to operate.

If you have a backup gen, no worries. Just mentioning the tank option as with a heat pump electric water heater, you'd have 60-80 gallons on tap during power outages.

Unless you can get some real dehumidification -- I don't see any advantage if you are needing to heat the room where the unit is located. We had a neighbor at the beach put one in a while back -- placed it in his garage ... seemed like a great idea at the time. It's already failed .. and it required service once prior.

 

[Denwood]

It makes more sense (energy wise) to use a heat pump water heater where the cooling effect (ambient) of the water heater can be taken advantage. Again, for an all electric solution it’s hard to beat. I’d definetely read some reviews first to find brands with better reliability.

We are using a condensing heat pump dryer (same idea) which is ventless, and does add some heat to our basement which is a desirable in our climate. Drying times are longer but overall power use is 30% of a typical dryer.

 

[Lelandwelds]

To reiterate: the best combination would be a tankless plus a tank-type heater. Two ways to do it.

1. Big tankless water heater, NG or electric, feeding a small electric water heater, small like 5 gal. Recirc pump keeps the hot water lines hot throughout the house, and that small amount of heat loss is made up by the 5 gal tank. When you turn on a faucet the tankless does the heavy lifting.

2. Standard size tank-type heater fed with a medium sized tankless. Can do a recirc system or not. A tank type heater can deliver about 70% of its volume before a significant water temperature drop. So a 60 gal tank has 42 gal of actual available hot water. If you feed this tank with a tankless, then the incoming water is hot so you have 100% of the tank capacity available for a "dump" load like filling a large tub or multiple hot water draws at the same time.

I think I would want the tank feeding the tankless. Why pay expensive on demand heat just to fill a tank?

I would add a third option. Cheap tank feeding better tank. Keep the cheapie turned off until company comes. It will bring water temperature from 52°F up to ambient just by sitting there.

 

[nsula_country]

I think I would want the tank feeding the tankless. Why pay expensive on demand heat just to fill a tank?

I would add a third option. Cheap tank feeding better tank. Keep the cheapie turned off until company comes. It will bring water temperature from 52°F up to ambient just by sitting there.

And now you have a 6yr tank and a +12yr tank to worry about rusting out...

ECOSmart tankless are all copper and brass inside...

CT

 

[PT Doc]

I'm sure it's been discussed but the added cost of maintenance chemicals and the time to do it unless you have soft or softened water.

 

[kinglew]

put in noritz also
five years ago replace my50 gal power vent tank propane that was leaking went to tankless.great great save over 50 percent of propane used over tank.very happy camper

 

[kinglew]

The tankless electric water heater I was looking at used 3 40 AMP breakers, my electrician saying that if we go this route he will need to upgrade from a 200 amp service panel to a 400 amp. An extra $500 on his end, not to mention extra $ with the utility company.

At this point not sure its worth it?? Might just go with a traditional 50 gallon tank, with digital temp. adjustments.

take from a electrician which iam they **** energy stay way gas or propane good electric super bad

 

[kinglew]

Oh Also, had a friend use Electric tankless water. it keep blowing the CB all the time. Come to find out the plumbing for the heater came from below not from above...He had to reroute the plumbing to come down the wall (from attic) to the unit instead of up to the unit. not sure why but it fixed his problem....never popped the CB again. Also he said it was a power Hog....

electric tankless power hog big time

 

[kinglew]

I make my living as a Plumbing Engineer designing schools, hospitals, and all types of commercial buildings. My recommendation is not to use a tankless electric water heater. Use a tank type heater. Just to give you an idea a 4.5 KW tankless heater will give you a temperature rise of about 30 degrees F flowing 0.5 GPM.
In a home you will need 24 to 36 KW for a tankless heater. The problem with most larger tankless heaters is that the flow rate to turn on the elements is high enough that a lavatory faucet may not turn on the elements. There are some new tankless that claims to have the low flow issue fixed.
With the new energy requirements and tank insulation requirements there is not that much stand by heat loss.
Just to add if you can go with gas the gas heaters are really good.

noritz solved that problem 8 plus years ago just i trickle fire up talk from my own home tankless out perform a tank .

 

[kinglew]

No. I didn't misunderstand the function of a tankless water heater. My comment was in comparison to the tank style it replaced. I had hot water much sooner when we had a tank. The tankless has a delayed start before the burner lights.

And yes, when it's winter and I'm standing under the cold water issuing from the shower head that comes out of our well tank while waiting for the hot water for 45 seconds, it's an issue! (Talk about shrinkage!) I have one of those corner shower enclosures with half round doors and have to be standing inside to start the shower lest I flood the floor by opening the doors.

I would think the recirc pump would 'cause the tankless to run all the time and defeat part of the purpose for having a tankless.

recirc works great best tankless system you could have save 50 percent of propane used over my old tank .witch was a powervent high eff tank

 

[kinglew]

The OP may have gotten the answers required by now. Maybe not...

I have an update on the EcoSmart tankless electric water heaters. As previously mentioned we installed two 27kw units in a parallel configuration. About a month ago I noticed one of them not working. Got busy and forgot about it. Figured it was toast. Been only using one since and temperature has been as low as 20's at night. No idea what ground water temp was.

This week started looking at threads and parts for them. Found out they have a control power fuse. It is a standard size (1/4" x 1 1/4") glass fuse, 3/16 amp (.187 amp). Opened unit up and found the fuse holder, blown fuse. Had some 1 amp fuses and viola! Workie again!

Some people claimed they had to replace fuses several times a year. Mostly due to power surges and such. Even for a control power fuse, (.187 amp AC) seems light... Have no problems using a 1 amp. These have been going since 2011 and this is the first fuse. Have 4 more as spares.

Just an FYI. They are very reliable, just require large capacity of current in use.

CT

get the right fuse it is size to protect electronic control system.

 

[rburke65]

I'd vote for the water tank Hester.

 

[nsula_country]

get the right fuse it is size to protect electronic control system.

TROLL!

kinglew, you have 7 post history and 6 of them are in this thread.

Welcome to the forum, but don't TROLL...

FYI, I have since purchased correct fuses. But 1 amp fuse in a control circuit is pretty standard. Most are 1 amp to 3 amp, depending on design. ECOSmart erred on the side of conservative when they chose a .187 amp fuse. 12+ years as an E&I Tech and then EE... I've seen a few control circuits!

CT

 

[u3b3rg33k]

Rinnai has tankless systems designed for recirculation. might be worth a look. also might be worth considering a manifold system if you're going to play with the plumbing - by massively reducing the volume of your pipes they don't hold much, so you get hot water at the faucet very quickly.

 

[terabitdan]

I don’t know where some of you are finding tank water heaters that are about the same efficiency as tankless.

According to the manufacturer ratings gas tank models range from about 56-62%, tankless are 88-96%. Sure, you can buy tanks like a Polaris which are in the same range as tankless, but they cost the same or more money.

That’s 35% less gas used to produce the same amount of hot water.

That doesn’t mean everyone can get payback or savings over the life of a tankless. That depends on your usage, but it’s significantly more efficient.


Sent from my iPhone using Tapatalk

 

[kinglew]

TROLL!

kinglew, you have 7 post history and 6 of them are in this thread.

Welcome to the forum, but don't TROLL...

FYI, I have since purchased correct fuses. But 1 amp fuse in a control circuit is pretty standard. Most are 1 amp to 3 amp, depending on design. ECOSmart erred on the side of conservative when they chose a .187 amp fuse. 12+ years as an E&I Tech and then EE... I've seen a few control circuits!

CT

sorry not a troll just post on a subject that i have knowledge in.did all lot of reserach on tankless before i installed my noritz

 

[Radix2]

I don’t know where some of you are finding tank water heaters that are about the same efficiency as tankless.

According to the manufacturer ratings gas tank models range from about 56-62%, tankless are 88-96%. Sure, you can buy tanks like a Polaris which are in the same range as tankless, but they cost the same or more money.

That’s 35% less gas used to produce the same amount of hot water.

That doesn’t mean everyone can get payback or savings over the life of a tankless. That depends on your usage, but it’s significantly more efficient.


Sent from my iPhone using Tapatalk

The OP has no gas. So it is between electric tank and tankless.

He wants showering and washing at the same time, so it gets to be a pretty stout and expensive (if possible at all) electrical system to power a tankless. Both are close to 100% efficient from a water heating standpoint, the difference is standby losses. With a well insulated tank it is going to be pretty small savings for an active family, and the 30a circuit for a 50g tank is dead simple and cheap.

 

[yeldogt]

I don’t know where some of you are finding tank water heaters that are about the same efficiency as tankless.

According to the manufacturer ratings gas tank models range from about 56-62%, tankless are 88-96%. Sure, you can buy tanks like a Polaris which are in the same range as tankless, but they cost the same or more money.

That’s 35% less gas used to produce the same amount of hot water.

That doesn’t mean everyone can get payback or savings over the life of a tankless. That depends on your usage, but it’s significantly more efficient.


Sent from my iPhone using Tapatalk

Really a question of actual savings -- the typical family does not spend much heating water with a typical tank using NG. So how much is the savings going to be with a tankless? ... in the shoulder season before my pool heater goes on I'm at around $25 for gas -- and we have a dryer and large stove that we use often. What will I save going tankless? $5 a month? .... a decent tank uint will last 10 years with no cost .... No one I know has that much luck with tankless. And they cost more vs what you will save.

Tankless are great if you need endless water -- I have one on a dedicated outdoor shower at the beach. We also have to clean it every year -- the second bathroom needs to be done every two .. and they are expensive to fix and replace. Tanks are cheap.

 

[JRC3]

I went with a tankless. I did it more for space than anything else. https://www.garagejournal.com/forum/attachment.php?attachmentid=666352&d=1500263125 I don't think it's worth the extra money. After factoring in the stainless concentric flue and service valaves, I might change my mind in hindsight. It is nice to have the extra space though.


This is the best of both worlds. https://www.menards.com/main/plumbi...22-c-8690.htm?tid=3831045143943448835&ipos=17 The footprint of a 29g and the output of a 50g. I put one in for a buddy with 2 children and a teenage boy and he loves it, never runs out of hot water.