new home with 90 second hot water

[ahr6912]

Only one problem both hot and cold hub in that laundry room in concrete then goes the perspective areas. So, you need to pipe everything from the attic down to the laundry room, master bath, kitchen, and guest bath. Then the recirculation line from eaches further runs in that area back to the tankless and still need the check valves, balancing valve, and aquastat pump. Unless you live in California and afraid of Legionalles in the water lines.

 

[Twowaxhack]

The way I’ve proposed would be one continuous loop.
To start the pipe would come from point D and use your existing piping under the slab to the laundry room and continue to point A.

At point A the pipe would go up the wall to the attic and over to point B and down the wall and back up the wall and over to point C down the wall then back up to the attic and over to point D which is the water heater.

One loop. No balancing valves.

 

[Twowaxhack]

If they piped a manifold under the slab in the laundry then they screwed you. No if an’s or but’s about it, that is plain ignorance.

 

[Twowaxhack]

You could put a 10gal electric tank in and one of those circulator pumps with the bypass valve in. I know one pump will do at least two bypass valves, you could check if it would do three. If not you’d need to get another pump and valve.

https://www.homedepot.com/p/Grundfo...t-Water-Recirculation-Pump-99452459/308844533
You can buy extra bypass valves. Put one under each sink. The laundry would not need one since that’s where the header is.

The center bath may not need a bypass if you’re willing to wait just a few seconds for hot water there. It’s close to the header that will stay hot. You could try it and always add a bypass if needed.

 

[Hamberg]

Seems like a huge cost for 1.5 minutes?!

In a different trade 23 years ago when my home was built; it takes 135 secs (first thing in the AM) for hot water in our master bath, its just the way it is - can’t imagine spending $$ to pick up a minute when there's at least 60 seconds worth of other stuff I need to do. JMOFWIW...

 

[ahr6912]

Great help. Thank you. Here is a pic of that laundry room manifold/hub where the cold and hot get distributed to the various areas. As it will turn out I'm going with a mini hot water heater 4gal under the sink model by Bosch. Price 199 as for the 2.5 gal 152.

 

[Twowaxhack]

Great help. Thank you. Here is a pic of that laundry room manifold/hub where the cold and hot get distributed to the various areas. As it will turn out I'm going with a mini hot water heater 4gal under the sink model by Bosch. Price 199 as for the 2.5 gal 152.

Be sure to run your 3/4” relief lines to a safe discharge point for each heater. In my location that would typically be outside.

 

[ahr6912]

Seems like a huge cost for 1.5 minutes?!

In a different trade 23 years ago when my home was built; it takes 135 secs (first thing in the AM) for hot water in our master bath, it's just the way it is - can’t imagine spending $$ to pick up a minute when there are at least 60 seconds worth of other stuff I need to do. JMOFWIW...

Sorry to hear that. Damn, I'd "move to where to food is" as the slogan goes. But, thanks to modern science under the sink water heater is born. For a minimum of $$ 150-200 and practically no additional plumbing except for a brass reducer or two. You got instant hot at any predesignated temp until the stagnant water in the hot water pipe gets hot through that under the sink water heater from the gas tankless in the garage. Used it in the kitchen back at my other home when I first moved up here. Great invention. Thanks again. Keep your idea on hand for your next home project.

 

[Twowaxhack]

Sorry to hear that. Damn, I'd "move to where to food is" as the slogan goes. But, thanks to modern science under the sink water heater is born. For a minimum of $$ 150-200 and practically no additional plumbing except for a brass reducer or two. You got instant hot at any predesignated temp until the stagnant water in the hot water pipe gets hot through that under the sink water heater from the gas tankless in the garage. Used it in the kitchen back at my other home when I first moved up here. Great invention. Thanks again. Keep your idea on hand for your next home project.

You’ll also need to add dedicated electrical for each water heater.

Poor design costs money doesn’t it ? That’s what I’ve always said anyway.

 

[ahr6912]

You’ll also need to add dedicated electrical for each water heater.

Poor design costs money doesn’t it ? That’s what I’ve always said anyway.

Well said. Like the dedicated electrical, too. Smart. The cicurt breakers in these homes now have the GFCI already included in the back at the breaker box. Thus, eliminating more money from my pocket. At close to 45$ a piece for each. As opposed to the wall-mounted ones like 15$ that you can run two of our three duplex outlets from.

 

[Twowaxhack]

Seems like a huge cost for 1.5 minutes?!

In a different trade 23 years ago when my home was built; it takes 135 secs (first thing in the AM) for hot water in our master bath, its just the way it is - can’t imagine spending $$ to pick up a minute when there's at least 60 seconds worth of other stuff I need to do. JMOFWIW...

Thats too long of a wait for me, I guess I’m impatient.

I take two showers a day so I’d be waiting on hot water for 30 minutes a week. And at 2gpm roughly 8 gallons a day down the drain.

Double all that because my wife is on a different schedule.

 

[ahr6912]

Wow, that is crazy.

That's too long of a wait for me, I guess I’m impatient.

I take two showers a day so I’d be waiting on hot water for 30 minutes a week. And at 2gpm roughly 8 gallons a day down the drain.

Double all that because my wife is on a different schedule.

 

[Hamberg]

You’ll also need to add dedicated electrical for each water heater.

Poor design costs money doesn’t it ? That’s what I’ve always said anyway.

Big yellow extension cord would work !

 

[Mitchell-DIY-Guy]

You’ll also need to add dedicated electrical for each water heater.

Poor design costs money doesn’t it ? That’s what I’ve always said anyway.

For an under sink model for the kitchen, I'll use a 2.5 gallon model. That can share the outlet with the disposal, via an "air switch" which toggles the power from disposal to hot water. Easy peasy...

But unless you have some crazy ass bathroom design, there is unlikely to be an outlet underneath that sink! If you are a ranch house or on a crawl space you may be able to easily add one from below. On a slab, or if this is a second floor, you may find yourself a little bit challenged...

 

[Twowaxhack]

For an under sink model for the kitchen, I'll use a 2.5 gallon model. That can share the outlet with the disposal, via an "air switch" which toggles the power from disposal to hot water. Easy peasy...

But unless you have some crazy ass bathroom design, there is unlikely to be an outlet underneath that sink! If you are a ranch house or on a crawl space you may be able to easily add one from below. On a slab, or if this is a second floor, you may find yourself a little bit challenged...

That’s a great idea after the inspector left. They would want a dedicated circuit for each appliance.

Here they would also want it in a safety drip pan as well and piped to the outside or a suitable drain.