Saving water here in California buy installing mini water heaters at point of use.

[Pmaru77]

I'm remodeling a bathroom right now and am trying to figure out these mini water heaters and what to do. First off, the bathroom sink, it takes too long and we waste water waiting for the hot. I've installed the Armitron before with great results. They were like 4 gallon electric water heaters under the sink inside a vanity or such. The problem with those, is the emergency overflow that needs to be dumped outside (I believe). Can the dump into the drain? Probably not. The second option is these in the wall tankless water heaters (electric) that can easily be fitted almost anywhere, provided you can get a 20 or 30 amp power line to it. They have no overflow dump valve to worry about. Either one of these would save me water, but add to the electric. Seeing that the future of water looks grim, and that electricity can eventually be from solar, I still want to do this for the sink.
Question, for a bathroom sink, I think I would hook up a cold water line to it? So that is the sink (easy decision).

For the shower, right now we occasionally bucket the excel cold water down the stairs and use it for the pool or garden (some work involved) plus there is only two of us. If we are diligent, that is the best of the best. But since I have everything apart and see that they make tankless water heaters that fit inside the wall, I'm tempted to hook up one of these, and have no idea if I would hook up the hot line or the cold line of water. It would depend on the tech. of the heater I'm guessing. To do or not to do? Me thinks these heaters are not proven to last? Plus you need a access door which I'm OK with. It would be nice if they worked. Any help out there?

 

[Reach4]

Two more possibilities:
1. put in a hot water circulating system to let the existing natural gas provide the hot water.
2. Feed the new little point-of-use electric water heaters with hot water from the water heater. That would keep you from running out of hot for a long shower (if the shower is going through the little electric unit).

I don't know about the point-of-use tankless units saving water for hand washing. They take a minimum flow to turn on I think.

I don't think it is permissible to have the temperature and pressure valve to feed its water directly to the drain.

 

[Sponsor]

 

[Pmaru77]

Two more possibilities:
1. put in a hot water circulating system to let the existing natural gas provide the hot water.
2. Feed the new little point-of-use electric water heaters with hot water from the water heater. That would keep you from running out of hot for a long shower (if the shower is going through the little electric unit).

I don't know about the point-of-use tankless units saving water for hand washing. They take a minimum flow to turn on I think.

I don't think it is permissible to have the temperature and pressure valve to feed its water directly to the drain.

I like option 1 you have but have no idea how to do it, or how complicated it would be.
I can still run a pipe to dump outside for the tank option, but would have to do more work. I do not have room for a tank for the shower.
The mini tankless takes .3 gpm to turn on, and looks like they are designed to put out .5 gpm which is ok for a bathroom sink.

I wish the wife didn't need so much hot water. I'm fine with cold or luke warm. Except for cold showers.

We are lucky there is only 2 of us. I cannot imagine having a family of 4 or 6. As it is, I see a big jump in utilities elect and water when we have extended guests.

 

[Dana]

In most cases you can use the cold line as the return to the tank on a KISS recirculation system. The down side to that is you will have tepid water above room temp on the cold side of the bathroom taps right after the recirc has run a cycle.

The simple D'MAND recirculation kits where you call the hot water with a button are more energy efficient and less failure prone than those that are set to keep the water at the taps hot 24/7:

With this approach the folks who are fine with cold/tepid water hand washing and those who insist on hot water right now both get their way, and you don't waste water in the shower waiting for hot water to arrive.

 

[Pmaru77]

In most cases you can use the cold line as the return to the tank on a KISS recirculation system. The down side to that is you will have tepid water above room temp on the cold side of the bathroom taps right after the recirc has run a cycle.

The simple D'MAND recirculation kits where you call the hot water with a button are more energy efficient and less failure prone than those that are set to keep the water at the taps hot 24/7:

With this approach the folks who are fine with cold/tepid water hand washing and those who insist on hot water right now both get their way, and you don't waste water in the shower waiting for hot water to arrive.

Wouldn't you need one of those gizmos at each sink/shower?
SO you turn on hot water and the water returns to the heater until the hot gets to the faucet and then the valve does its thing?
Or just one and put it the furthest away?
I think I get it. When you open any hot water source, you are sending pressure to the gizmo and it lets water flow through it until it reaches temp. and then it closes and you get hot out of the faucet you have turned on. ?

 

[Reach4]

As I understand it, you push a button at the point of use, which may be hard wired or wireless. One pump turns on, and then you turn on a faucet some amount of time later.

 

[Pmaru77]

As I understand it, you push a button at the point of use, which may be hard wired or wireless. One pump turns on, and then you turn on a faucet some amount of time later.

Yeah, there must be a pump to pressure the water past the street pressure. I think that implies that you need the pump on whenever you need hot water anywhere in the house. and the switch could be activated wirelessly for remote locations. Not thrilled about drinking water out of a water heater, but we do have a new water heater

The city is giving incentives for catching rain water, up to $400 worth of rain barrels. You'd think the next thing is something like this.

I've got a "casa" down in Mexico and have 2 tankless hot water heaters, one for the shower area and one for the kitchen area that run off of their own propane tank. Wonderful. Especially because of the water coming from a 1100 litre water tank.

 

[Reach4]

Not thrilled about drinking water out of a water heater, but we do have a new water heater

You can run a separate return line. The return line does not necessarily have to be as large as the main line.

 

[Jadnashua]

You'd put the cross-over at the point of use furthest from the water heater. If everything is along a main line, then, when the pump runs, everything before it will also be hot. If you have significantly long branches off of the main line, you might need more than one, or to move the pump back to the WH and use more than one cross-over device. You'd only need the cross-over devices if you can't put in hot water return lines.

The system I have is made by RedyTemp, and, if you have power where it needs to go, literally can be installed in about 10-minutes. I have mine set on a timer so that it only runs when I'm typically up, and this particular model, does not run constantly...mine tends to run maybe 45-seconds maybe 3-4x per hour. It has an adjustable aquastat and I have it set to shutoff when the hot water is warm. Since the shower and everything else is before that system, they're hot. I find that flushing the toilet (it's a 1.6g) also clears the warm water out of the line. Prior to installing it, my shower took over a minute to get hot, now, about 5-seconds to clear the cooled off water in the short leg from the main. Everyone's piping layout will likely be a little different, so your results may differ. My unit is close to 15-years old and still going strong with no maintenance.

If you're heating with NG, adding electrically heated tanks, can eat up a fair amount of power. FWIW, for other than maybe hand washing, you'd need LOTS more power than 20-30A for an electric tankless system. That amount of power works okay for a small tank, but not a tankless.

 

[Dana]

Wouldn't you need one of those gizmos at each sink/shower?
SO you turn on hot water and the water returns to the heater until the hot gets to the faucet and then the valve does its thing?
Or just one and put it the furthest away?
I think I get it. When you open any hot water source, you are sending pressure to the gizmo and it lets water flow through it until it reaches temp. and then it closes and you get hot out of the faucet you have turned on. ?

You're not sending pressure to the gizmo- the gizmo is opening up a valve and pumping water from the hot plumbing to the cold plumbing (or a separate return line to the cold side of the hot water heater) until the hot water arrives, at which point the valve between the hot & cold closes and the pump stops.

You only need one per remote tap area, not one per sink. In a bathroom the shower pluming & sink plumbing are usually drawing from the same distribution pluming- they don't have two separate home-run lines all the way back to the hot water heater, one for the shower, another for the sink. If using a flow-sensing type it's important to put the sensor before the branch between the sink & tub/ shower.

While you could install a separate return line from the remote tap back to the cold side of the hot water heater, in retrofits it's usually easier to use the cold distribution plumbing and just put up with having tepid water at the cold taps that's somewhat above room temp for ~10-15 minutes after the call for hot water. (In a shower the tepid water condition is gone well before the shower is over, but if calling hot water just for short draws such as hand washing it can persist for awhile.)

 

[JerryR]

The system I have is made by RedyTemp, and, if you have power where it needs to go, literally can be installed in about 10-minutes. I have mine set on a timer so that it only runs when I'm typically up, and this particular model, does not run constantly...mine tends to run maybe 45-seconds maybe 3-4x per hour. It has an adjustable aquastat and I have it set to shutoff when the hot water is warm. Since the shower and everything else is before that system, they're hot.

I just installed a Redytemp TL4000. I have probobly 150 feet of pipe run from my electric water heater to our master bathroom. Prior to installing the pump it was taking over 3 minutes of running the master bath shower hot water before it got hot.

Right now with the SS braided hoses supplied with the pump it takes 2 minutes before getting hot water at the pump. I still want to reduce the time and I feel that the SS Braided hoses are restricting flow. I already replaced the angle stops with full flow 1/2" ball valves. I've ordered a pair of high flow Stainless Corrugated 1/2" flex lines to replace the braided lines hopefully this will increase flow and speed up hot water.

I already had some X10 devices to control the nightstand lamps so I added a X10 momentary relay at the pump. I only use the pump on demand. I have several X10 RF transmitter switches, one at nightstand, one in master bathroom and one in the pool bathroom to turn the pump,on a single cycle.

I had my local electrician install a receptacle in the sink cabinet and self installed the pump.

I trip the pump before brushing my teeth and hot water is at the shower when I'm done brushing.

I'm considering installing an additional on demand smaller pump, ATC-3000, under the kitchen sink which is much closer to the Hot Water Heater for use when we need hot water in kitchen.

I'm very happy with the results.

 

[JerryR]

Right now with the SS braided hoses supplied with the pump it takes 2 minutes before getting hot water at the pump. I still want to reduce the time and I feel that the SS Braided hoses are restricting flow. I already replaced the angle stops with full flow 1/2" ball valves. I've ordered a pair of high flow Stainless Corrugated 1/2" flex lines to replace the braided lines hopefully this will increase flow and speed up hot water.

UPDATE: I replaced the SS Braided hoses with 1/2" SS Corrugated flex lines and this reduced the time for hot water from 2 minutes to 1 min 15 seconds.