Instant Hot Water?

FastEddieB

FastEddieB

Touchdown! Greaser!
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Oct 14, 2013
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Lenoir City, TN/Mineral Bluff, GA
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Fast Eddie B
Our new TN “Pole Barn” seems well thought out regarding both electrical and plumbing. One thing that could be improved however is the long delay in getting hot water to the kitchen sink.

I recall my parents had something installed in their D.C. home that provided near instant hot water at their kitchen sink. I think it was appropriately called an “Insta-Hot” or some such.

I see devices such as this on Amazon:

51006664155_e783ddab8a.jpg


Installation looks pretty straightforward.

Anyone have experiences or recommendations regarding these before I pull the trigger?

Thanks in advance.
 
The electric ones are probably just a small tank water heater - 2-6 gallons, with the intention being to keep water available for the surge. They will come in 120 or 240 and are not tankless. For washing your hands, it should be fine. For a dishwasher or washing machine, maybe not. Installation should be a DIY job.

If you want constant hot water, you want a (more expensive) gas fired tankless model. Unless you are certified with gas, you'll need to call someone to at least install the gas line.

I'll add in, don't discount insulating your pipes in the crawlspace. I suspect TN, like NC is far enough south that they tend not to run water lines inside the house like they have to do up north.
 
If you do tankless, look carefully at the energy requirements. While the power (electric or gas) is only needed when water is running the amount needed during that time is considerably higher.

When I had to replace my hot water tank last year, I looked at a tankless. It would have required a new line from the gas meter, an analysis by the gas company, and an up sized meter. All that would have added about $1000 to the cost, and about 2 weeks to the timeline.
 
My thought was to feed the 4 gal tank with my existing hot water line. That should give enough hot water for most quick rinses. I suppose if I exceed that, there will be a “gap” of cold water when the hot water tank lines kick in?
 
I have those insta-hots in a small satellite office that doesn't have a water heater. Boss wanted a sink in every exam room and that was the only way to do it. They work to wash your hands, but that's about it. You dont have a source of sustained hot water. Not a problem as nobody needs to take a shower or do the dishes with it.

When my dad built his house, he put in a heavily insulated 1/4in recirc line with a small pump at the far end of the system. The pump was on a timer so it wouldn't create excessive losses. If you needed hot water between 7 and 9am or in the evening it was instant. If you needed hot water at 1am, you had to wait until it came through.
 
FastEddieB said:
Our new TN “Pole Barn” seems well thought out regarding both electrical and plumbing. One thing that could be improved however is the long delay in getting hot water to the kitchen sink.

I recall my parents had something installed in their D.C. home that provided near instant hot water at their kitchen sink. I think it was appropriately called an “Insta-Hot” or some such.

I see devices such as this on Amazon:

51006664155_e783ddab8a.jpg


Installation looks pretty straightforward.

Anyone have experiences or recommendations regarding these before I pull the trigger?

Thanks in advance.
Click to expand...
Pretty standard in apartments I've rented in Europe, so we decided to get one a few years ago when our tank was fading. It takes a few seconds to fire up (ours is natural-gas powered), but then the water stays hot as long as you want — for a few months last year we had six adults living in the house (my daughters and their partners both moved in for a while), and it was great never running out of hot water, even with back-to-back long showers.

Note, though, that "instant" depends on how far the heater is from your tap. If it's in the bathroom in a small apartment, you'll get hot water right away. If it's in the basement and you're on the second floor, with 50 ft of pipes in-between, you'll still have to wait a while for all the cold water in the pipes to clear before the hot water arrives, just like with a tank heater. The main benefit is that once it starts, it never runs out.
 
We actually installed a hot water recirculating pump onto our water heater about 6-8 months ago. The install was quite simple, and the water savings is reason enough to add one. No more waiting for the water to heat in the back bathroom - instantly hot water!
 
We had one at our place in Desert Aire. It was great for instant coffee or tea in the morning. But WAY too hot to wash your hands.

Funny, we are just the second night in our new house in Chehalis, and not more than 5 minutes ago I was wanting instant hot water. The microwave takes a minute. That's 6 hours a year.

I'm 75.........so that's 18 days of just waiting for hot water.
 
The insta hot type things are totally different than a tankless water heater (or heater with recirc pump). They are designed to have instant near boiling hot water available for things like making tea, formula for children or getting stuck on food off. You do NOT want to wash your hands in 97 dC hot water!!

FWIW - we have one and use it a lot but it isn't for just having fast hot/warm water on your regular faucet. For that, look to a recirc pump which will give you hot water in 2-5 seconds at the normal faucet.
 
RudyP said:
The insta hot type things are totally different than a tankless water heater (or heater with recirc pump). They are designed to have instant near boiling hot water available for things like making tea, formula for children or getting stuck on food off. You do NOT want to wash your hands in 97 dC hot water!!
Click to expand...
We got one in the rebuild of our kitchen a few years back. Handy for hot chocolate...dump the powder in the cup, hit it with the hot water, and you're done. Actually let us relegate the microwave to the closet. Great for cleaning sticky stuff off silverware (peanut butter, etc.) prior to putting them in the dishwasher.

It does have a tank, and I can hear it cycle as it keeps the water hot. Ours was installed with a separate faucet (vs. feeding the "normal" hot-water line to the main faucet), and that faucet has a small diameter. Ours developed a leak after a couple of years, and was replaced under warranty.

All-in-all, I'm kind of "meh" about it, but the wife wanted one in her "perfect kitchen."

Ron Wanttaja
 
FastEddieB said:
Our new TN “Pole Barn” seems well thought out regarding both electrical and plumbing. One thing that could be improved however is the long delay in getting hot water to the kitchen sink.

I recall my parents had something installed in their D.C. home that provided near instant hot water at their kitchen sink. I think it was appropriately called an “Insta-Hot” or some such.

I see devices such as this on Amazon:

51006664155_e783ddab8a.jpg


Installation looks pretty straightforward.

Anyone have experiences or recommendations regarding these before I pull the trigger?

Thanks in advance.
Click to expand...
I have one of these under my kitchen sink. It’s a small hot water tank. The end result is hot water immediately, warm water then hot water.
The time it takes for hot water to get to my sink from the big tank is longer than the time it takes to empty the little tank under the sink. It’s only noticeable if I’m filling the sink to wash dishes. For washing hands or a single dish it’s plenty of hot water.
 
wanttaja said:
We got one in the rebuild of our kitchen a few years back. Handy for hot chocolate...dump the powder in the cup, hit it with the hot water, and you're done. Actually let us relegate the microwave to the closet. Great for cleaning sticky stuff off silverware (peanut butter, etc.) prior to putting them in the dishwasher.

It does have a tank, and I can hear it cycle as it keeps the water hot. Ours was installed with a separate faucet (vs. feeding the "normal" hot-water line to the main faucet), and that faucet has a small diameter. Ours developed a leak after a couple of years, and was replaced under warranty.

All-in-all, I'm kind of "meh" about it, but the wife wanted one in her "perfect kitchen."

Ron Wanttaja
Click to expand...

That's about right. I've always liked having them but they tend to last 3-5 years and then need to be replaced. I have yet to find one super high quality, built-to-last version, which I would prefer, but they are cheap and pretty easy to replace so it isn't a huge annoyance.
 
weilke said:
...When my dad built his house, he put in a heavily insulated 1/4in recirc line with a small pump at the far end of the system. The pump was on a timer so it wouldn't create excessive losses. If you needed hot water between 7 and 9am or in the evening it was instant. If you needed hot water at 1am, you had to wait until it came through.
Click to expand...

^^^ This.

I build a sprawling bungalow at the ranch; did not want any stairs like our former city houses (we are getting older). The master bath is on the east side, the kitchen is on the south, the laundry room and dog shower on the north and the guest ensuites are on the west side, so I have plumbing everywhere.

Installed exactly what is described above with a 3/4 inch supply & 1/2 inch return loop around the house with a Grundfos timer pump. The hot water reservoir tank is a heat exchanger off the main heating boiler. Every fixture has immediate and virtually unlimited hot water during the hours we are normally awake.
 
I just installed a Rheem tankless heater in our house. It's not instantaneous, but it's unlimited (or as long as the propane holds out). A recirc kit is available for it to make it instantaneous, but that uses more gas keeping the water in the lines hot all the time. Gotta wait in the bathroom, but the heater is only 6' from the kitchen so it's not a long delay there.
 
If you really want instant hot water ...

 
GRG55 said:
I build a sprawling bungalow at the ranch; did not want any stairs like our former city houses (we are getting older). The master bath is on the east side, the kitchen is on the south, the laundry room and dog shower on the north and the guest ensuites are on the west side, so I have plumbing everywhere.
Click to expand...

Friends in Florida have a very long U-shaped home. Rather than distributing hot water, they have tankless heaters stuck to the outside wall wherever they need water inside. Also keeps the gas line outside of the house. Of course, that only works in a place that doesn't see hard freezes.
 
weilke said:
Friends in Florida have a very long U-shaped home. Rather than distributing hot water, they have tankless heaters stuck to the outside wall wherever they need water inside. Also keeps the gas line outside of the house. Of course, that only works in a place that doesn't see hard freezes.
Click to expand...

Interesting solution.
We bury the water supply lines around here a minimum of 8 feet below grade to make sure they don't freeze in winter. :)
 
I put an Insinkerator hot/cold fauct system on our kitchen sink. Its a 2 quart water heater tied to a filter for hot and cold beverages. Works great and we love it. Only draws 800 watts at 120V. So easy to install.
 
I think I hit a snag for a simple install.

I checked the breaker we have running to our 1/2 hp garbage disposal, which draws 6.3A. It’s the circuit that’s handy that’s easiest to tap into. It’s a 20A circuit which also feeds our very rarely used dishwasher, which itself draws 10.5A. The under-sink water heater we’re looking at draws 12A.

Running a new circuit to under the sink is likely to be very expensive. The only quick-and-dirty solution would be to install a switch to the heater and placard the dishwasher with instructions to turn off the heater when the dishwasher is in use. Or a switch to send power to either the heater or the dishwasher but not both.

Any clever ideas here?
 
The problem is low flow faucets and long runs. I put a circulator on mine, it has a return line and check valve. Basically pumps the cold water in the pipe back into the hot water tank. I get instant (like 2 seconds) hot water. Works great.

This looks like it works on the same principle except it pushes the water back via the cold water pipe rather than a dedicated line, I like the dedicated return better, but that could be an issue in some installs.

Watts Premier Instant Hot Water Recirculating Pump System with Built-In Timer - Sump Pumps - Amazon.com
 
I have a 220v electric tankless I used up in my barn. Worked reasonably well, ground water around here is about 55f and it boosted temp up to around 110F through a 1/2" supply line. Good enough for washing horses, not enough to take a shower.

I have the long run problem in the master bath sink. Hate wasting the water waiting for it to get hot enough to shave. We have domestic h/w from a boiler, so once it gets hot, it stays hot. Thinking about installing another electric tankless under the sink to get instant hot water until thde boiler supply kicks in. Have to run another 220v circuit though. There's a dryer on the other side of the wall, but don't think they should share the circuit.
 
FastEddieB said:
I think I hit a snag for a simple install.

I checked the breaker we have running to our 1/2 hp garbage disposal, which draws 6.3A. It’s the circuit that’s handy that’s easiest to tap into. It’s a 20A circuit which also feeds our very rarely used dishwasher, which itself draws 10.5A. The under-sink water heater we’re looking at draws 12A.

Running a new circuit to under the sink is likely to be very expensive. The only quick-and-dirty solution would be to install a switch to the heater and placard the dishwasher with instructions to turn off the heater when the dishwasher is in use. Or a switch to send power to either the heater or the dishwasher but not both.

Any clever ideas here?
Click to expand...

When I was looking to do the same thing you are - put tankless system in kitchen sink because main water heater is a long ways away - that was the biggest constraint I found - power or gas flow constraints. Our house was built in '95 when 'over building' was obviously not on the mind of the folks that built this place, so we have bare minimum for power and gas plumbing. It seems like when I was looking that there were some REALLY small systems (1-2 gallons) that might fit the bill if you're just wanting to not have to wait for hot water when washing hands or rinsing something off quick. Have you figured out how much water has to flow through the line before you get hot water from your main tank? You might not need as much capacity as you think you do if you put it inline with the existing hot water line.
 
It looks to us like the biggest unit that will fit under the sink is 4 gals. Right now the plan is to run it off the same circuit as the garbage disposal and dishwasher with an inline switch and placarding the dishwasher (which only very rarely gets used) with instructions to turn off the water heater when dishwasher is in use. We do plan on putting it inline with the hot water line, realizing there will be a "cold water gap" when we exceed the 4 gal capacity.
 
FastEddieB said:
a "cold water gap" when we exceed the 4 gal capacity.
Click to expand...

There shouldn't be a problem as long as you don't have more than 2 gallons or so of lines between you and the main hot water heater.

I went back and forth repeatedly on my design, from a small tank to a small tankless to recirculation and back. The closest bathroom is about 1 sink-water-minute away from hot water. The other one is about 2 minutes. The tentative plan is a recirc pump with a thermal valve between the hot and cold at the end of the line with a fancy self-built controller so either a button or flow on the line enables the recirculation for the appropriate time. So, turn on briefly, turn off, wait 15 seconds and tada, hot water. Like all things all I need is time...
 
chartbundle said:
There shouldn't be a problem as long as you don't have more than 2 gallons or so of lines between you and the main hot water heater.

I went back and forth repeatedly on my design, from a small tank to a small tankless to recirculation and back. The closest bathroom is about 1 sink-water-minute away from hot water. The other one is about 2 minutes. The tentative plan is a recirc pump with a thermal valve between the hot and cold at the end of the line with a fancy self-built controller so either a button or flow on the line enables the recirculation for the appropriate time. So, turn on briefly, turn off, wait 15 seconds and tada, hot water. Like all things all I need is time...
Click to expand...

The recir I have has a temp control that actuates when the water in the pipe cools, that's all available commercially. End result is hot water within a second or two. Tank is about 50 feet away.
 
This is one of those things that I can't believe hasn't been fixed better here in the great old US of A. When I lived in Europe 40 damn years ago, they had mini instant tankless heaters at every faucet or other hot water outlet. No central water heater.

The hot water was instantaneous, HOT, and they only used half as much pipe when plumbing the house. Why we haven't done the same in the intervening 40 years blows my mind.
 
flyingcheesehead said:
Why we haven't done the same in the intervening 40 years blows my mind.
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It's about money.

It's cheaper to plumb two systems in the house than to install multiple localized hot water heaters. In my house, that would be 4 of them at cost of something like $5000. Compare that to copper pipe at about $1.80/ft.

Why do they care? 1) because the builder with the lowest cost makes the most money and the plumber with the lowest cost gets the job. That lowest cost is not going to be tankless water heaters.
 
bflynn said:
It's about money.

It's cheaper to plumb two systems in the house than to install multiple localized hot water heaters. In my house, that would be 4 of them at cost of something like $5000. Compare that to copper pipe at about $1.80/ft.

Why do they care? 1) because the builder with the lowest cost makes the most money and the plumber with the lowest cost gets the job. That lowest cost is not going to be tankless water heaters.
Click to expand...

Lowest cost to install, yes. But the operating costs should be WAY lower on the localized ones, since you're not spending money to keep a tank of water hot for the 23 hours a day where you're not using hot water. For people who live in cookie-cutter neighborhoods, well, I expect that they'll get a crappy cookie-cutter home. But there's plenty of people who are more involved in the process of building new homes, and to them the equation should be different. However, even the availability is a problem here. I'm not sure you can even buy the sort of thing I'm talking about here to this day.
 
Builders and plumbers don't get an incentive to build a system with a low operating cost.

Relatively few people build their own houses.
 
I have an instant hot water faucet installed in our kitchen sink. It's on a timer and I have hot water only in the morning when I make my drip (Chemex) coffee. It's on from maybe 5AM to 10.

Others are probably similar, but it is quite a clever design. The little tank is not pressurized. Instead when you turn the valve to get hot water, the valve actually adds cold water to the bottom of the little tank, displacing the hot water which then comes from the top of the tank to the faucet. The result is zero risk of explosion, no pop-off valve to leak, etc. If I turn the heat too high all that happens is that the faucet bubbles and burps a little bit until the element shuts down.

I have no idea what the electricity cost is and I don't care.
 
flyingcheesehead said:
Lowest cost to install, yes. But the operating costs should be WAY lower on the localized ones, since you're not spending money to keep a tank of water hot for the 23 hours a day where you're not using hot water. For people who live in cookie-cutter neighborhoods, well, I expect that they'll get a crappy cookie-cutter home. But there's plenty of people who are more involved in the process of building new homes, and to them the equation should be different. However, even the availability is a problem here. I'm not sure you can even buy the sort of thing I'm talking about here to this day.
Click to expand...

My last cookie-cutter home actually had two electric water heaters. One fed a riser to the kitchen and and master bath on one and of the house, the other fed the kids bathroom and a main level washroom on the other end. That worked quite well in terms of the time to get hot water.

What didn't work well was the distribution of the air from the hvac. Both air handlers were at on one far-end of the house leaving the opposite end lacking for either heat or cooling. Oddly enough, the compressors for both were at that end of the house, so they both had really long linesets with the associated losses. A true 'wtf were they thinking' design.
 
flyingcheesehead said:
This is one of those things that I can't believe hasn't been fixed better here in the great old US of A. When I lived in Europe 40 damn years ago, they had mini instant tankless heaters at every faucet or other hot water outlet. No central water heater.

The hot water was instantaneous, HOT, and they only used half as much pipe when plumbing the house. Why we haven't done the same in the intervening 40 years blows my mind.
Click to expand...

LOL. That's easy to answer. If you lived for the first 900 years of your nation's existence in houses built from large quantities of piled up rocks when you finally got back from your tour of Empire and got around to thinking about central heating and hot water, you'd pretty well be forced to install a heater at every faucet too. Face it, its an even bigger retrofit problem than @FastEddieB is dealing with. :D As for central heating, they appear to have given up on it completely. No go with those walls. :p

Thankfully the French went to Canada, the British lost, and we have been spared such plumbing marvels as separate cold and hot water faucets at each sink. ;)

BTW, does anybody know...does the PIC sit in the right front seat in a British airplane?
Just askin' :cool:
 
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chartbundle said:
There shouldn't be a problem as long as you don't have more than 2 gallons or so of lines between you and the main hot water heater.

I went back and forth repeatedly on my design, from a small tank to a small tankless to recirculation and back. The closest bathroom is about 1 sink-water-minute away from hot water. The other one is about 2 minutes. The tentative plan is a recirc pump with a thermal valve between the hot and cold at the end of the line with a fancy self-built controller so either a button or flow on the line enables the recirculation for the appropriate time. So, turn on briefly, turn off, wait 15 seconds and tada, hot water. Like all things all I need is time...
Click to expand...

Don't bother with fancy self-built. I got one of these from Amazon for my heated horse trough. $20, works great.

https://www.amazon.com/dp/B011VGASL...abc_9ANPJ05RDSXFTAFBK8J5?_encoding=UTF8&psc=1
 
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