Will this work

[john in la]

I have a 50 gallon water heater within a couple of feet of my master bathroom so hot water is not a problem here.
My kitchen is the next room over plus my dishwasher has a water heater in it.
So if this was the end of the story I could set my water heater very low saving money.

The problem is I have a second bathroom with a shower and clothes washer in it.
It takes the hot water several minutes to reach this room as it clears all the pipes of cold water in the entire house.
I realize a hot water circulation setup would be best but this will not allow me to turn the water heater way down.
So I am thinking of adding a small under the counter tankless water heater where the line comes into the room.
It will heat the cold water as the lines get purged. Then it could supplement the warm water to make it hot enough for the clothes washer and shower.

My question is will the savings in turning the electric water heater down say 20 degrees pay for the under the counter tankless heater as this is the only room I need extra hot water for because of the shower and clothes washer.

 

[joeysmith]

Yes itll help
Its actually a preferred to have a tanked water heater in front of a tankless unit
Would be best to get one that you can set the output temp on so the water doesn't get hotter while you are in the shower

 

[Phill Tibbetts]

From what I have heard the on demand water heaters are not cheap to run, but that's just what I hear, no experience. Don't ask the person selling them because they will tell you how efficient they are. IMHO

 

[MM-TX]

Can't answer your question about savings but I have used this brand for years in 2 houses and they don't crud up like others I had before that. They are infrared. I have not found any other mgf that sells a infrared heater. We have very hard water and old galvanized pipe and have crapped out a few tankless heaters. SioGreen

 

[circus]

A smarter solution is to run long hot water branch lines from closer to the water heater. Code dictates water main size but the branches can be small. One for the shower and one for the washing machine. 3/8" tubing holds 1/4 the water a 3/4" tubing holds so hot water comes 4 times faster. Less wasted hot water cooling in the pipes too. Assuming 3/8 is big enough.

 

[flying belgian]

I'm in Mn where we heat the house 9 months a year. I never felt like hot water from the water heater was wasted. By the time I run the hot water through the pipes up to my furthest bathroom and it runs back through the house out the drain pipe the water is cold. All that heat is in my house somewhere.

 

[showcrop]

look into the system that takes cold water from water heater inlet and uses it to push the hot water from the pipe back into the tank when flow stops. Of course it requires an additional line but it can be small diameter. It has been years since I looked into it but it looked very attractive.

 

[MarkB_MI]

How cool are you thinking you'll lower the water heater temperature? It really needs to be at least 120F to keep bacteria from growing in the tank.

 

[Mule Meat]

I don't see you saving money.
First you lower the temperature in tank A by 20 degrees. It is going to kick on much faster due to the temperature of the cold water coming in from the supply line mixing with what's in the tank.

"It takes the hot water several minutes to reach this room..."

Meanwhile tankless heater B is going to kick on to heat the water coming from tank A. By that time the temperature of the water in tank A is low enough for the tank to kick on. So now you will have two water heaters using power to heat water at the same time..

If you replumb the system by cutting off the hot water supply from tank A and use tank B as a stand alone system only heating water for the second bath. Then you may save a few pennies. Maybe.

 

[Russ from MN]

Our house is about 55 feet long, the main water heater and most of the plumbing is in one end, however, the bathroom with shower that I use is in the far other end. I added a 2.5-gallon tank type heater in the crawl space under my bathroom, in series in the hot water line, problem solved.

 

[Blackhole49]

No idea on the cost savings (personally I don't see it). Because you really don't have a winter, your situation is much different than mine. Turning the heater down 20* depends a lot on what you have it set at and how hot you like your showers. you will use a lot more 100* water than 120* taking a shower because of the lack of cold mixing water being used and the water in the tank getting cooled faster from the cold replacement water. This is going to cause your current heater to run longer to recover. For me, I envision getting hot water at the far end of the house quicker, but no cost savings. If you do it, hope I'm wrong.

 

[stevieb49829]

I'm in Mn where we heat the house 9 months a year. I never felt like hot water from the water heater was wasted. By the time I run the hot water through the pipes up to my furthest bathroom and it runs back through the house out the drain pipe the water is cold. All that heat is in my house somewhere.

Or melting the snow and ice on top of your septic tank!

 

[showcrop]

I'm in Mn where we heat the house 9 months a year. I never felt like hot water from the water heater was wasted. By the time I run the hot water through the pipes up to my furthest bathroom and it runs back through the house out the drain pipe the water is cold. All that heat is in my house somewhere.

No. effluent often comes out very warm.

 

[da.bees]

The pou heater also adds value in the form of convenience. You can save a little money by setting top t-stat in 50 gal to temperature you want at shower but setting bottom stat at a lower temperature. Say supply comes into heater and hits bottom stat at 70*F, bottom element raises water to 85*F, top stat set to 105*F kicks in when 85* hits it but only has to raise temperture 20*. Savings is realized by lower part of tank giving up less heat that if set to 105*. Put an overcoat on the heater to reduce heat lose or don't and consider lost heat as suplimenting home heat like the Belgian said.

 

[john in la]

The water heater has a slip over insulated coat. It is set to unknown factory set temperature but it must be just above 120 as it is not very hot. 100 would be great as the only one that uses my master bath tub is my toddler grandson and then only if he gets into a mud puddle while playing in the yard. My dishwasher has a built in water heater.
Basically my water heater is at the wrong end of the house with the old person shower and laundry at the other end.

What got me on this quest in the first place is my wife saying we can only wash clothes in cold water because the tub is full by the time the hot water gets to this room. That and the wasted water in shower waiting on the hot water.

But now that Mark brought up the bacteria I have to switch gears. Leave the big water heater at 120 and investigate ideas of supplementing hot water to laundry shower room.

Mark also has we wondering why bacteria will grow in my 100 degree water heater but I don’t have to worry about it growing in my well tank sitting in a 4x4 shed in my yard in 100 degree summers.

 

[Nordic]

The best house improvement we made this year was exactly what Russ from MN did. At the count of five the water is HOT out of the tap. The test of patience is gone and any difference on the power bill seems negligible. Even if it costs a few cents, it's worth every penny in the daily improvement to living in our house.

 

[Ray,IN]

Instant hot water from another perspective: https://www.energystar.gov/products/demand-hot-water-recirculating-system
Install this with a switch in the electric line so you can turn it on 5 minutes prior to running the washing machine or showering.

 

[MarkB_MI]

Mark also has we wondering why bacteria will grow in my 100 degree water heater but I don’t have to worry about it growing in my well tank sitting in a 4x4 shed in my yard in 100 degree summers.

I think you do have to worry. It's a good idea to sanitize your well and plumbing once a year with clorox.

Water heaters in restaurants run very hot, but then use a tempering valve to cool the water to a safe temperature. I think that's both to supply enough hot water to keep up with demand but also to prevent bacteria from growing in the water heater.

I think the main concern is legionnella, which flourishes in temperatures between 77 and 113 fahrenheit.

 

[BarnyardEngineering]

Mark also has we wondering why bacteria will grow in my 100 degree water heater but I don’t have to worry about it growing in my well tank sitting in a 4x4 shed in my yard in 100 degree summers.

Except that you do have to worry about that... you've just been blissfully ignorant of it all this time.

 

[john in la]

Except that you do have to worry about that... you've just been blissfully ignorant of it all this time.

I guess I’ve been lucky.
My well system is completely sealed and the water comes from 200 feet in the ground so how is harmful bacteria suppose to get into the water in the first place to start growing.

Educate me on this subject.