Hot Tap Water...Faster

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T56MaxTorq

T56MaxTorq

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My wife loves to watch the show, "Shark Tank" where folks take out bad loans for worse ideas. I'm always daydreaming about how I can improve anything that I don't like or am annoyed with while I watch. I hate cold water from my tap in the morning, as I'm sure everyone else does. Sit there for a minute to wait and wait for hot water to shave, shower, etc. watching your hard earned money and perfectly clean water go down the drain. Not to mention the residual hot water gets trapped and cools as soon as you turn it off, waste of energy. I had a solution that could speed up hot water and waste less when it sits. There's some expensive commercial products that give you instant hot water but waste energy far more by having a secondary hot water heater close to the faucet.

So why not have smaller diameter, higher pressure plumbing in the home? You'd need a boost pump, small gauge pipe and a debooster at every hot faucet. For example, If you were to cut the pipe ID in half and double the pressure in that pipe, you'd have the same flow after deboosting but spend half the time waiting, waste half as much water and half the energy leaving residual hot water in your pipes. Increase the pressure and lower the diameter and the saving yields would be even better.

So without plumbing all new hot pipes to retrofit an older home, I thought about snaking the small diameter pipe through existing pipe. The hard part would be snaking the new water line. Would have to be done with a boroscope of some sort but what the hell would I do at a T fitting and what could possibly hold double or triple the water pressure?? Just a thought.
 
A on demand water heater under the sink does the same thing. Insulating your pipes helps also. The more hot water you use the hotter the pipes get almost up to the water temp. When there is no longer flow, the water and pipes cool. Insulation will help but eventually it will cool to room temp. High pressure will get the hot water to the faucet only as fast as the water comes out of the faucet. (flow vs. pressure) You could have a closed loop system with a return back to the water heater and a circulation pump but that would continually use energy. Waiting for a gallon of cold water to clear out of a pipe is about as efficient as you can get.
 
Yeah those on demand systems waste a lot and take too much maintenance when you have hard water. Plus you need a unit for every faucet. I don't even know if they can keep up with a hot shower. I could take the waste down to a quart instead of a gallon with smaller hot pipes.
 
I have no idea the cost, but it is nice to turn on the hot water and hear a click and instantly have hot water. Never had a problem with the shower either. Been using since I bought the house 6 years ago. My energy costs are much less than my last home. Still am always interested in the next great idea.
 
Tadams said:
I have no idea the cost, but it is nice to turn on the hot water and hear a click and instantly have hot water. Never had a problem with the shower either. Been using since I bought the house 6 years ago. My energy costs are much less than my last home. Still am always interested in the next great idea.
Click to expand...

Haven't heard of a real user of an on demand system, do you mind sharing the brand and model of the unit?? Thanks for the input. I've only heard hearsay
 
I'm not home now, but I know the one in the master bath is Eemax. Model SP3012
I had written that number to have one installed in my office.
Once you are accustomed to instant hot water, it seems to take forever to have hot water from a conventional system
 
Hey Colorado... are you a 420 blaze it kind of guy? They have been using these on demand systems almost exclusively for years and years in the European Theater. Don't know where the big *** water storage tank idea came from in the west. I believe it's short sighted economics that play the part here in america. Big is cheaper to install but costs more in the long run. A lot more. As far as sediment...... Ha!!!! The water moves through the pipes as heated and creates no sediment. Hard water issues I'm unsure of, but I have had no trouble with mine for over ten years and it cut my bill by almost $40 a month, and would be even cheaper if it wasn't all electric here.
Also, they have systems that are constant recycling systems that give instant hot water but they cost more because the water is constantly cycled. Your idea would also require a way to increase the water pressure over what your cities system provides. More moving parts and more things to go wrong. Wait.... Your on to something. More maintenance for an upgraded system creates more jobs. Your a genius. Somebody needs to run with this.
Your idea does have some merit but I wouldn't try to feed new lines thru old. Maybe just add sleeves in the long straight runs to decrease volume within the pipe. Bypassing the problems of turns and tee's.
 
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Tadams said:
I'm not home now, but I know the one in the master bath is Eemax. Model SP3012
I had written that number to have one installed in my office.
Once you are accustomed to instant hot water, it seems to take forever to have hot water from a conventional system
Click to expand...

Thanks! No rush. Im sure that once accustomed to Instant hot water, it has got to be sooo nice that going back to conventional style must be annoying.
 
I had an issue with my on slab house for slow hot water (up to 3 minutes) seemingly. The master bath is the closet to the WH and was not an issue, but the kitchen and 2nd bath were horrible. I installed a recirculating pump at the WH and a special valve under the sink in the second bath which is the farthest away point. The pump has multiple timer set points that I programmed around our usual water use times.
Problem solved!

Instant Hot Water Recirculating System with Built-In Timer - Watts
 
Blind Squirrel said:
Hey Colorado... are you a 420 blaze it kind of guy? They have been using these on demand systems almost exclusively for years and years in the European Theater. Don't know where the big *** water storage tank idea came from in the west. I believe it's short sighted economics that play the part here in america. Big is cheaper to install but costs more in the long run. A lot more. As far as sediment...... Ha!!!! The water moves through the pipes as heated and creates no sediment. Hard water issues I'm unsure of, but I have had no trouble with mine for over ten years and it cut my bill by almost $40 a month, and would be even cheaper if it wasn't all electric here.
Also, they have systems that are constant recycling systems that give instant hot water but they cost more because the water is constantly cycled. Your idea would also require a way to increase the water pressure over what your cities system provides. More moving parts and more things to go wrong. Wait.... Your on to something. More maintenance for an upgraded system creates more jobs. Your a genius. Somebody needs to run with this.
Your idea does have some merit but I wouldn't try to feed new lines thru old. Maybe just add sleeves in the long straight runs to decrease volume within the pipe. Bypassing the problems of turns and tee's.
Click to expand...

I've been in the military for 12 years and maintain turbo-prop engines, I have no care for weed. I thought of this idea after studying aircraft brakes, which use high pressure hydraulics, then deboosted that pressure to actuate the braking piston. Not sure what you mean by "create sediment," it's impossible to create anything that is not already there. There's always going to be junk in your water at min levels, I had simply thought that this scale, lime, calcium, etc builds up over time in an on demand system, whether it's in the heat exchanger or the heat element itself I don't know - reducing the overall heating efficiency over time.

It's good to hear people's on demand systems actually last.

As far as my design goes, the only moving part is the water pump - which is pretty simple and perfected these days. The debooster is all mechanical, as is a regulator, but to turn on the pump during a demand would take a Hobbs switch. Being able to throttle the pressure for various demands would require a more complex regulator and of course a relay.

The snaking through the pipes would only pertain to homes that have burried interior piping like multi stories. Someone with a crawl space like me it would be as simple as removing the old pipe and adding a small high pressure pipe.
 
My house has a full basement with the hot water heater in the basement. Running the pipes would be simple, but I am very satisfied with what we have. The unit in the bathrooms run the sinks and the shower, and do a nice job of supplying hot water for a family of 5.
 
I haven't studied up on the on demands but I did broaden my knowledge on our boiler replacement a few years back. 3500 square feet and it heats the house heating only a couple gallons at a time. I got a Weil McLain energy efficient boiler. In essence it is a "on demand" design. Saved me $100 a month average on my heating bill over the old 6' long cast iron boiler we had.
 
toolmanmike said:
I haven't studied up on the on demands but I did broaden my knowledge on our boiler replacement a few years back. 3500 square feet and it heats the house heating only a couple gallons at a time. I got a Weil McLain energy efficient boiler. In essence it is a "on demand" design. Saved me $100 a month average on my heating bill over the old 6' long cast iron boiler we had.
Click to expand...

Damn $100 a month?? That's impressive. My design is just a theory and really just a side thought when I was bored. I also never understood why the water heater and the furnace don't share the same heat exchanger, I suppose because one goes bad before the other and people huck the whole thing out in favor for another. I thought it was so cool long ago when I first saw an atv starter that was also the alternator. We could all save space, weight, moving parts if things had dual purpose.
 
We had "on demand" water heater. $370 for a new heat exchanger every 3 years. Took that POS to the dump few months back. Replaced with a tank electric. Less water is ran to get hot water. Only have to run the wafter long enough to get water from the tank to the faucet to get hot water.
 
We have had 3 separate units for 6 years and have no issues whatever. I am completely satisfied and would replace them without any question if and when something happens to the ones we have
 
Maybe some designs are junk compared to others. I've only heard the bad stories so I thought it was inferior design all together and wasted electricity to run it. I'm assuming they use a super heating element in a vacuum insulated tank with some computer control. I just don't know where I would put 3 of them in my house lol maybe in the crawl space
 
Small unit in the bathroom fits under the sink in the cabinet. Feeds both the sink and the shower off one unit. Home has 3 baths, so same set up in each one. Not a large unit and his no storage tank to take up space. We still have the traditional large hot water heater in the basement closet next to the washer and dryer units.
 
nice! That eemax is pretty slick! Computer controlled and super heats the water as it flows through. Im guessing as the hot water from the big water heater catches up to it, it throttles back the electricity to maintain a constant temp then probably shuts off completely as the big water heater takes over. lol I don't think I could compete with that design! Except that a good amount of residual hot water is wasted in the pipe, essentially the reason for the eemex heater in the first place. I'll have to do the math one day to see if my idea is even worth it.
 
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T56MaxTorq said:
Damn $100 a month?? That's impressive. My design is just a theory and really just a side thought when I was bored. I also never understood why the water heater and the furnace don't share the same heat exchanger, I suppose because one goes bad before the other and people huck the whole thing out in favor for another. I thought it was so cool long ago when I first saw an atv starter that was also the alternator. We could all save space, weight, moving parts if things had dual purpose.
Click to expand...
 
T56MaxTorq said:
Damn $100 a month?? That's impressive. My design is just a theory and really just a side thought when I was bored. I also never understood why the water heater and the furnace don't share the same heat exchanger, I suppose because one goes bad before the other and people huck the whole thing out in favor for another. I thought it was so cool long ago when I first saw an atv starter that was also the alternator. We could all save space, weight, moving parts if things had dual purpose.
Click to expand...
You are exactly correct and that option was available but the installer didn't recommend it, separate units if one fails. Replacement water heaters are much cheaper than the domestic water add on to the heating system.
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Every wonder why most government offices have the instant hot water, it is less expensive. When we had ours installed the company recommended against the whole house unit. I don't remember the cost, we had a heat pump replaced at the same time
 
I have had a closed loop system in a couple of homes. Neither had a circulating pump as the water heater was in the basement. The water would rise as heated and return as it cooled thus self circulating. I'm sure a pump would be better but it doesn't take long to get hot water without.
Yote
 
Tadams said:
Every wonder why most government offices have the instant hot water, it is less expensive. When we had ours installed the company recommended against the whole house unit. I don't remember the cost, we had a heat pump replaced at the same time
Click to expand...

I thought that was from all the bums that bathe in the sink before I got there. J/k
 
We have a closed loop plumbed on the hot water side and a small circulating pump at the water heater. Instant hot water at every faucet. This was done 20 years ago, so I thought it would be common today.
 
RockinRobin said:
We have a closed loop plumbed on the hot water side and a small circulating pump at the water heater. Instant hot water at every faucet. This was done 20 years ago, so I thought it would be common today.
Click to expand...

Yeah that's what I put in only the pump is set to run only during expected usage times.
 
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