Any plumbers here?

[Alpo]

I'm thinking of replacing my wore out water heater with an on-demand unit.

 

Researching them, there seems to be two types. The whole house type, which would replace my current water heater, and smaller ones that would be put in the bathroom and another one in the kitchen

 

I see having one underneath the kitchen sink would mean I wouldn't have to wait for hot water, but it just seems like that would be more expensive, since I would need one in the kitchen for washing dishes and two more - one for each of the bathrooms - and then the fourth one for the utility room for the washer.

 

If you were putting it on demand heater in your house, which way would you go? Whole house, or individual units?

[Michigan Slim]

While house if I was doing it. Keep it simple. Big money to run electric or gas to each location. 

I'm not a fan of them overall. I had one on a well and it couldn't ramp up and down well enough to match my water pressure changes. 

[T.K.]

I put one in my house. The shower in the master bedroom which is the furthest from the heater just takes a few seconds to get hot, but thats all. This can be solved by putting one of the small units in the bathroom, but ill just live with it. Going tankless was the best move i ever made.

I was told by a licensed plumber

That i would have to run a 3/4" gas line, etc and a cost of @$3000 etc. Which is total BS. I installed it with the existing 1/2" gas line and have never had a problem. Its been 15 Years or so.

Edited April 7 by T.K.
More info

[Cold Lake Kid, SASS # 51474]

I have a Whole House, Natural Gas unit, but my home is 2 story, so I have to run the taps for a while to get hot water, from the basement to the bathrooms on the second floor.

Just something to consider depending on where the On Demand unit will be in relation to the point of use.

[Sedalia Dave]

First thing to look at is will it pay for it's self.  Skip the percentages of savings they are meaning less. Look at real dollars. My typical summer time gas usage is about $5.00. Would take forever for one to pay for itself.

 

I researched putting them under the sinks to reduce the time it takes to get hot water.  The problem is most of them require more amperage than is typically available in either location. A 1500 watt heater is pulling 15 amps. Means that it will have to be on a dedicated circuit or it'll blow the breaker when its on and you plug in anything else that pulls much current.

 

A whole house unit requires a lot of power. At a minimum you'll need 200 amp service for an electric unit. Depending on how many other large electric appliances you have (Stove/Oven, AC, baseboard heat, etc) You may need to upgrade to 400 amp service.

 

For gas units you may need to have a higher capacity meter or bigger lines installed for it to work.

 

So be sure to weigh the initial expense vs the time to pay it back.

[Cypress Sun]

 

I can't speak for the plumbing, only for the electrical portion of the deal. The below only applies if your existing water heater is electric, not gas.

 

For each unit you install, you would need a separate circuit to each unit. You can't just tap off of an existing circuit for this purpose. Wattage and voltage depends upon the unit. Each circuit would need to be installed from your electrical panel to each unit. An electrician is going to get expensive, real quick...more than likely negating any savings on not needing to run the water to get hot. Keep in mind that the under sink ones will not heat your shower without an (somewhat) extensive plumbing repipe also.

 

No matter what the salesmen claim about the inline/on demand water heaters, they don't save you money. The water still takes as long to get hot as it did before, only now it has about twice as much power consumption as a regular 4500 watt water heater does. The wiring that is presently at your existing water heater will, more than likely, be inadequate for an on demand water heater as most of the on demand units require a #8 conductor and a 40 - 50 amp breaker. Many people get a unwelcome surprise by this when the plumber comes out to swap out the water heater and the wiring/breaker is not adequate.

 

Another thing about on demand water heaters is that the very second that the hot water is turned on, that entire wattage/amperage of the on demand water heater is at full load amps, in other words...it's more expensive powerwise.

 

Everyone I know that had an on demand water heater installed, replaced them with a standard water heater after a few years.

 

I would go with a tank type water heater. I installed a 30 amp, 2 pole switch for mine. I turn it on for an hour in the morning and an hour at night. Works great, saves money and is easier on the unit as it doesn't cycle on/off all day and night.

 

YMMV

 

 

Edited April 7 by Cypress Sun

[Alpo]

My water heater has been in use for 7 years. It now produces about 1 gallon of hot water.

 

When my daughter's family was here over Thanksgiving we hook the hose up to it and drained it out the back door. I had the hose end, and stuck my hand in the flow. Felt like it was full of sand.

 

I have come to the reluctant conclusion that I need a new water heater, which is why I was contemplating the on-demand.

 

I did notice, while I was looking at them on home depot's website, that it was going to take a whole bunch more electricity than the 40 amp 220 breaker my water heater uses now.

[Marshal Mo Hare, SASS #45984]

I had my 40 gal heater replaced by a tankless, both were propane.  I had one extra request. I wanted faster hot water to the kitchen sink, because I used it a lot. I could see the route that hot water was taking to get there, a length of inch and then 3/4 inch pipe before getting to the 1/2 inch for the kitchen. After rerequesting this, I got the water wait down by 30 seconds, 90 secs to 60.

[Father Kit Cool Gun Garth]

When I take my shower first, Ann gets hot water on demand when she goes next. 

[Ozark Huckleberry]

4 hours ago, Alpo said:

When my daughter's family was here over Thanksgiving we hook the hose up to it and drained it out the back door. I had the hose end, and stuck my hand in the flow. Felt like it was full of sand.

 

I have come to the reluctant conclusion that I need a new water heater, which is why I was contemplating the on-demand.

Have you considered:

 

1. Draining and flushing the water heater -- not just once, but a couple of times until the sediment is cleared, and;

 

2. The problem might be the elements and/or thermostats. I had a similar problem and solved it by just replacing the elements.

[Pat Riot]

13 minutes ago, Ozark Huckleberry said:

Have you considered:

 

1. Draining and flushing the water heater -- not just once, but a couple of times until the sediment is cleared, and;

 

2. The problem might be the elements and/or thermostats. I had a similar problem and solved it by just replacing the elements.

I would go this route first. A water heater should last longer than 7 years. 
I would call a local water heater repair. It could save you money and hassle. 

[Rye Miles #13621]

I had to replace my hot water tank after only 8 years, it was leaking from the bottom, it was a piece of junk. Hopefully the one I got is better so I was told. I stayed with the old natural gas whole house heater. The tankless option was way more expensive and since I’m by myself I didn’t think I needed it.

[Buckshot Bob]

For people who don’t want to wait for hot water you can install a recycle loop with a small pump that constantly recycles the hot water. I’ve seen it done in allot of larger homes where there’s a long run to the bathroom or kitchen. If you do this insulation on the pipe will save you some cash in the long run. My longest run is to the kitchen, I just accept it’s going to need to run a little, I did insulate the pipe and that seemed to help a little, my plumbing is in the basement where it’s always at least 60 so if you’re in a crawl space you might see more of a difference. 
About 8 years ago we got natural gas “had propane before” my furnace and hot water heater were old and for what it was going to cost me to switch them both over to natural gas I decided to just replace them . I got bids from about 5 different companies and every one of them didn’t recommend installing a tankless water heater for allot of the reasons stated above. 

[Texas Joker]

1 hour ago, Pat Riot said:

I would go this route first. A water heater should last longer than 7 years. 
I would call a local water heater repair. It could save you money and hassle. 

Yep. If sediment built up it'll short the bottom element.

 

Drain the tank. Use heat to bend a 3/4 inch pvc length 90' into an L shape. Tape the pipes long leg to your shop vac hose.  Pull your elements and inspect/ replace. Slide your pipe into bottom element hole and clean out the sediment/scale. Reassemble.

 

Less than 40 bucks at lowes gets you 2 elements and an upper/lower thermostat. 

[Cypress Sun]

8 hours ago, Alpo said:

My water heater has been in use for 7 years. It now produces about 1 gallon of hot water.

 

When my daughter's family was here over Thanksgiving we hook the hose up to it and drained it out the back door. I had the hose end, and stuck my hand in the flow. Felt like it was full of sand.

 

I have come to the reluctant conclusion that I need a new water heater, which is why I was contemplating the on-demand.

 

I did notice, while I was looking at them on home depot's website, that it was going to take a whole bunch more electricity than the 40 amp 220 breaker my water heater uses now.

 

As others have stated, sounds like the tank needs flushing/cleaning at the minimum. Because of the "sand", the bottom element probably needs to be replaced also. If the tank isn't leaking, I would replace both elements and both thermostats. BTW, that's not sand, it's actually deposits from hard water.

 

Replacement of these items and the flushing/cleaning can be done by either a plumber or by you if you want to save money. If the work is done by a plumber, get a quote (price) first. Tell them that you'll have the tank drained BEFORE they get there as this takes time and they charge by the hour.

 

Assuming that the wire that goes to your water heater is a #10, which almost every electric water heater is wired with, the breaker should be no more than a 30 amp breaker, not a 40.

 

Based upon what I've seen around here, element/thermostat replacement is $200 -300. Tank type water heater (40 gal) is $800 -1200 which includes them supplying the heater.

 

If you do the job yourself, make sure that you turn the breaker for the unit off before draining it.

 

For the record - I replaced my water heater a few years back, doing the work myself. It was actually pretty easy to do. All I really needed was a plumbers tubing cutter (already had), emery cloth, Teflon tape (white tape for the threads), a pair of Shark Bite flexible hose connecters (bought at HD), short piece of 3/4" pvc w/male connector (for the pressure relief valve to drain into the pan if needed) and two red wirenuts (already had). I reused the pan under the old heater. The Shark Bite hose connectors are a GREAT invention. One of the SB flex hose connectors was just a normal one with a threaded male connector at one end and a slip on connector at the other end. The other SB flex hose connector was the same thing, only with a shut off valve for the cold water side.

 

The secret to do it yourself water heater replacement is to match up the heaters as close as you can in height, width and connection location. It helps tremendously to have room to work on the heater also. Mine in the garage with about a foot of room on either side and nothing above it, so that helped and was easy to work on. Being in the construction trade for 40+ years and seeing how plumbers do things helped a lot also.

Edited April 7 by Cypress Sun

[Chantry]

Keep in mind that a conventional hot water can serve as a source of fresh water during an emergency.  I think the water heater I have is a 30 gallon tank , which means about one gallon of water per day for a month.

 

And I would see about fixing the one you have before spending money and doing a comparison between the long term costs of each method.

[Still hand Bill]

I had a on demand 15 years ago and hated it.  Took forever to get hot water, then would get a slug of cold if you stopped for even a second. It froze one winter and we went back to a tank.  They take a ton of energy as it’s hard to heat the water quickly without lots of heat.  This is why tank heaters work.  Small heater, longer time to heat the water.  
 

if I was to do it again, I would try an on demand with a small tank as those are supposed to address the slugging issue and long heat up times.  Also my new house is a better location as gas on demand need to be close to a outside wall.  They can have to use special exhaust vents due to the high heat.  

[Ozark Huckleberry]

20 minutes ago, Chantry said:

eep in mind that a conventional hot water can serve as a source of fresh water during an emergency.  I think the water heater I have is a 30 gallon tank , which means about one gallon of water per day for a month.

Good point.

 

When we lost power from a hurricane, we still had water pressure, a the tank kept the water hot enough to make brief showers reasonably comfortable for a few days while we waited to get power back. 

[Texas Jack Black]

 It all depends on your power source NG ,LPG, or Electric. Also how many people living in the home. Your expected  years left at that site ETC. and more .

A lot to think about .

 They are not for me 

 

Best Wishes

[Pat Riot]

When I lived in that “four letter word” state, California, there were plumbers that offered a service of annual water heater tank flushing and inspections. 
The first house I bought in ‘93 was built in 1962. The water heater looked to be a mid-70’s model. I flushed the tank and there were a lot of these weird little globs of semitransparent goo in the water that came out of the tank. Along with little bits of what I think was mineral deposits and sediment. It was like miniature gravel. 
Shortly after I flushed the tank the water heater died and sprung a leak. As luck would have it Home Depot had a sale going on. I got a new water heater and they installed it for the price of the water heater alone prior to the sale. 
I flushed annually after that and it worked great until I sold the house in 2005. 

[Texas Jack Black]

 The key to tank longevity is  maintenance and water quality.

PS I am not a plumber but I can read

[bgavin]

I looked into a tankless for our rental property, then went with a good quality conventional.
The tankless requires regular maintenance, meaning a scheduled event with the renters.
San Diego water has a high saline content, which might have posed a complication for an expensive tankless.

Be SURE you have a catch pan and drain under the heater.
When they let go, they make a big wet mess.
Mine was in an alcove off the kitchen floor... which got trashed when it let go without a catch pan.

I used my Harley bike jack to lift it up enough to slide it into place.
We were renovating the kitchen at the time, and I had to move a wall 5 inches to accommodate a standard diameter heater.
My house is 1960 vintage and the alcove was too small for a modern heater.

I chose a nat gas model that will light when our power goes out (frequently here).

 

[Dirty Dan Dawkins]

Electric whole house are generally 20-24 kw. 80-100 amps. 

[Forty Rod SASS 3935]

My thought is very simple:  I simply don't have room for under-the-counter-heaters....and the cost saving isn't enough and the convenience isn't enough to justfy it.

Edited April 8 by Forty Rod SASS 3935

[watab kid]

im going to replace mine this year i fear - its been a while and its not lasting long anymore - lot of sediment in the bottom from our hard water im sure , 

 

the on demand at point of use would require electric i suspect and you probably pay more for electric than gas as i do here , then there is running that electric to them as well as the plumbing at multiple locations , mostly not practical i think , and running gas then venting is more yet , 

 

the single point makes some sense but there is that time lag same as with what you have , if your already electric or gas you already have those issues taken care of at the central location , ill stay with my gas unit and call it good at this point in life 

 

i installed a lot of these in commercial locations over the state and surrounding states for a clients business , it paid for itself for him  as he washed over a 100trucks every day in each location , i dont think it will in a private home ,