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[Tim McCulloch]

I have an on demand electric hot water heater and I love it!

I've been running it for a number of years and it is the best thing ever. We love the never ending hot water. Take as many showers in a row as you want, it just isn't a problem. You simply do not have to manage your usage and worry about running out of hot water.

It replaced a propane tank unit so I had to run all new electrical for it. I think I put in something like 3x 240V 50A circuits for it. Fortunately it was located very close to the breaker panel so it really wasn't much of a problem.

If I were building a new house, I would put separate smaller units nearer the point of use, like one in the kitchen and one near the master bath and one near the guest bath. That way you don't have to wait for the hot water to traverse the house. You just have hot water, almost instantly. You can have as much hot water as you want, too. However, I don't think the tiny individual point of use units are that good. You know, the ones that go under the sink. They typically don't have the capacity to keep up with the temperature and flow that is needed.

Back when I was flipping houses...  for 2 of them we put in a typical gas water heater but only use it hold water at 80°F or so (usually the "vacation" setting) and install point of use heaters.  Small tankless electric heaters do their best when they only need to do a 20°-25°F temp rise, so gas does the big rise (50-ish to 80-ish) but holds at a lower, energy saving temp.  The point of use heaters consume less electricity due to the lower temp rise required and better keep up with the volume demand.  The hybrid approach puzzled realtors but in the houses we installed this way, the buyers were happy.  There's no reason this can't be done with a traditional electric tank heater, too, and especially the heat pump version Mike linked to.  My guess is the primary heating elements would see little use.

[John Roberts {JR}]

I believe I have enough electrical service to support tankless (since I no longer use the in-wall resistance heaters), but wiring in place to the hot water heater is way too wimpy for 50-60A tankless draw.

I like heat pump technology, but need a bunch more family members to justify the break-even from cost savings in my lifetime. 

 I am leaning toward a cheap basic old school water heater (1/3rd cost of high tech). From measuring the height of my old unit it is not as tall as a new normal sized unit so I will get a 38 gallon "lowboy", easier than re-plumbing the copper lines higher. 

I could add a junction box for the power drop, instead of just crude wire leads with black tape hanging out the side of the heater, but I noticed an old school 240v dryer outlet on the wall right behind my heater that is sitting unused, that measures hot... So that is making me wonder if my current water heater is 120V or 240V?  I also figured out where some of the funny wiring that didn't appear to be fused is going. Out behind my house in a panel below where the service meter is, there are a half dozen or so big breakers(?) Perhaps just switches? My guess is that the in-wall resistance heaters run from those breakers/switches.  Since they haven't been touched for 30+ years I am not going to mess with them now.

@ Steve... my whole house is probably one big code violation. I try not to do things that are overtly unsafe..like getting into the shower after feeling a tingle. I really almost did that. My rigged up added external ground wires for a couple GFCI outlets, probably isn't to code either. Shhh don't tell anybody.

 JR

PS; I still smell like sawdust. I can probably take one hot shower after I disconnect the power from old heater.  Maybe some cold showers if needed.

PPS: My new water heater is ready for pickup so time to hit the road. I'll pick up a 240V cord set. Hopefully this will be easier than I feared at first.   

[Mike Sokol]

I like heat pump technology, but need a bunch more family members to justify the break-even from cost savings in my lifetime. 

It pays to watch the sales and rebates. My son bought a house with a dead hot water heater, so we started pricing them. This same heat-pump hot water heater I linked to was listed at $1,200 at Lowes which seemed like a crazy amount to pay for instead of a standard electric HWH for $300. There was a sale that weekend that brought the price down to $1,000. He then filled out a new credit card application at Lowes which had a 10% discount incentive. So now the cost was $900. Our local POCO was offering a $500 rebate on it due to energy efficiency, so now the cost was $400. And he then got a $300 energy credit on his federal tax return, so the cost was now $100. I installed it for him, so there was no labor cost.  A standard electric HWH would have cost at least $300, while his new heat-pump HWH only cost him $100 and probably saves him $200 a year in reduced electricity costs. What's not to love?   

[Tim McCulloch]

It pays to watch the sales and rebates. My son bought a house with a dead hot water heater, so we started pricing them. This same heat-pump hot water heater I linked to was listed at $1,200 at Lowes which seemed like a crazy amount to pay for instead of a standard electric HWH for $300. There was a sale that weekend that brought the price down to $1,000. He then filled out a new credit card application at Lowes which had a 10% discount incentive. So now the cost was $900. Our local POCO was offering a $500 rebate on it due to energy efficiency, so now the cost was $400. And he then got a $300 energy credit on his federal tax return, so the cost was now $100. I installed it for him, so there was no labor cost.  A standard electric HWH would have cost at least $300, while his new heat-pump HWH only cost him $100 and probably saves him $200 a year in reduced electricity costs. What's not to love?

Our POCO encourages us to use more, not less...  But we're in Kansas, where we set our clocks back 50 years.

[Jonathan Johnson]

I believe I have enough electrical service to support tankless (since I no longer use the in-wall resistance heaters), but wiring in place to the hot water heater is way too wimpy for 50-60A tankless draw.

I see you've pretty much figured that out. Tankless electric water heaters do have high demand, requiring bigger wire and possibly bigger service.

And while they're more efficient over time, if everyone with an electric tank heater switched to electric tankless, we'd have to build a huge number of new power plants and upgrade the whole power grid just to meet the increased instantaneous demand when everyone in America jumps in the shower Monday morning.

The wavelength may be longer, but the amplitude is higher.

[John Roberts {JR}]

It pays to watch the sales and rebates. My son bought a house with a dead hot water heater, so we started pricing them. This same heat-pump hot water heater I linked to was listed at $1,200 at Lowes which seemed like a crazy amount to pay for instead of a standard electric HWH for $300. There was a sale that weekend that brought the price down to $1,000. He then filled out a new credit card application at Lowes which had a 10% discount incentive. So now the cost was $900. Our local POCO was offering a $500 rebate on it due to energy efficiency, so now the cost was $400. And he then got a $300 energy credit on his federal tax return, so the cost was now $100. I installed it for him, so there was no labor cost.  A standard electric HWH would have cost at least $300, while his new heat-pump HWH only cost him $100 and probably saves him $200 a year in reduced electricity costs. What's not to love?

I don't feel like waiting for a sale while my heater is still energizing my hot water pipes.

Tomorrow I'm going to disconnect the wires hanging out the side of my old heater and put wire nuts on them... Just for chuckles I'll measure the voltage, or search for a plate on the old heater with specs.

Had a little drama fitting the new heater inside my mustang (cobra)... I had to un-box it, to just fit it in barely. One guy in the parking lot was taking bets on whether I would fit it in...   Just another day in hickory as the worm turns.

I just checked the dryer style outlet again and this time no voltage??

Oh well I know the old drop is getting voltage...

JR

[Stephen Kirby]

A little NCVT swerve.  I recently rented an RV from a large national outfit.  As Mike is a big proponent of using NCVTs at campsites to verify the pedestal wiring, I have brought mine along the last few times I've rented one.  What was interesting is that none of the guys who do the orientations knew what it was when I showed it to them while they were going over the 120 hookup with me.

[Mike Sokol]

A little NCVT swerve.  I recently rented an RV from a large national outfit.  As Mike is a big proponent of using NCVTs at campsites to verify the pedestal wiring, I have brought mine along the last few times I've rented one.  What was interesting is that none of the guys who do the orientations knew what it was when I showed it to them while they were going over the 120 hookup with me.

Interestingly, I did a No~Shock~Zone orientation session at the Airstream RV plant two years ago, and once I showed them how a NCVT worked, they bought one for every RV tech in the shop and added it to their SOP for preliminary testing of trailers coming in for work. However, they won't promote the use of NCVT's to their customers since they think discussing shock hazzards will reduce RV sales. Oh well...

[John Roberts {JR}]

Interestingly, I did a No~Shock~Zone orientation session at the Airstream RV plant two years ago, and once I showed them how a NCVT worked, they bought one for every RV tech in the shop and added it to their SOP for preliminary testing of trailers coming in for work. However, they won't promote the use of NCVT's to their customers since they think discussing shock hazzards will reduce RV sales. Oh well...

yup people are funny... Imagine designing an outlet tester where they need to touch a metal contact while it's plugged in... "just trust me" 

OK update... I pulled the cover off the old school 240V dryer outlet and it was never wired up.. probably 40+ years in a humid environment.

I was needing a hot shower so I disconnected the voltage feeds to the old hot water heater. As soon as I removed the first hot wire (black) the voltage on my hot water pipes dropped to nothing. Even though my NCVT said the shower was safe, i disconnected the other hot wire (red), just to be super safe...  I am not sure why the voltage leak wouldn't persist with the one hot lead still connected feeding through the heat element to the voltage leak?

I'm now showered up  and running the load of dishes that backed up in my sink.. 


We'll see tomorrow what the plumbing hook-ups look like.

 I'll sleep a little better without energized plumbing in my casa.

JR

PS: Maybe I'll read the installation instructions tonight. Mike you'll like this, they recommend using a NCVT to confirm power is off.

[Mark Cadwallader]

Interestingly, I did a No~Shock~Zone orientation session at the Airstream RV plant two years ago, and once I showed them how a NCVT worked, they bought one for every RV tech in the shop and added it to their SOP for preliminary testing of trailers coming in for work. However, they won't promote the use of NCVT's to their customers since they think discussing shock hazzards will reduce RV sales. Oh well...

They just need to add a section to the owner's manual and include a NCVT with the purchase of a trailer or RV. Then it becomes an added benefit of their products, and prevents injuries and liabilty down the road. That will then establish a standard of care for the industry, and soon every RV and trailer will come with one.

Yep; just imagine a Airstream branded/logo'ed NCVT and Mini-Mag flashlight, in a little presentation case ....  Too cool.

[ProSoundWeb Community]