Lots of good comments! Here are my responses to the two most common comments: Comment: Electrical box needs to be grounded. Response: Yes, thanks, that problem has been fixed. Comment: Legionnaire's Disease / Legionella growth in "stale" water heater water. Response: After significant further research I have found so much conflicting advice on this topic from several "official" government sources. The EPA for example recommends setting your water heater to 120F (49C), while OSHA specifically states that temperatures of 120F will foster Legionella growth and recommends setting temperatures to 140F (60C). The CDC recognizes this and specifically states "Sometimes maximum temperatures allowed by your state may be too low to limit Legionella growth." My schedule (as shown in this video) and water heater temperature settings (140F) should not pose any risk for Legionella. However, if you are attempting this project you should do your own research, but based on mine a reasonable solution seems to be to make sure that your water heater hits 140F (60C) continuous for at least 1 hour per week. In my case my water will hit this sanitation range every day. Thank you to everyone for your concern and bringing this to my attention.

Inserting a simple ($10) digital timer into the low voltage Thermostat line worked well for me at a fraction of the cost. This works for most types of water heaters (Electric, Gas, Indirect) Always turn off the power before making any modifications!

A couple NEC things you'll want to add. The MC cable should have a clamp to prevent pull out. Since the box is metal and you're using MC on one side, the box should also be grounded. Also this one is minimal since the box is high but NEC doesn't allow for open punch outs when the box has live circuits inside it. Finally, the MC you cut open should have an anti-shorting bushing added to it. It's just a small plastic piece that protects the cables from the inside shaft pieces on the metal cladding left behind. A bag is $3 at HD

This sounds great when you have a purely resistive electric water heater. My old gas water heater just rust out and started leaking. We installed a new Heat Pump Water Heater and it is rated to use $130 per year of electricity per year. Compared to normal electric heaters, that is incredibly efficient, and turning it off and on wouldn't help much. Edit: The water heater in the thumbnail is actually a Heat Pump Water Heater which is partially why I watched and then left a comment.

You are right about checking the wires with a multimeter. When I installed my water heater timer, I thought I flipped the water heater breaker, but turns out it was one of the baseboard heaters. Luckily, I checked the wires for current before proceeding.

Great video! Proper verification of voltage: 1) confirm the voltage meter works 2) shut off power 3) test for no voltage 4) test the voltage meter at another source to verify this works. This takes into account if the voltage meter is working still. These are the steps before we enter any electrical switchgear.

Living on a boat in Canada over the winter I learning something quickly. Leaving the heater going all day even when not on the boat really increases the power bill(of course). Dropping the heatings(or even turning them off) it takes fooooorever(less than 10c) to reheat the boat and in turn more ON time more $$... because now you are not only heating the air temps you are also heating everything thats physical on the boat(wood, metal). The best way I found was to keep it in the middle, from a comfy 21-22c to 15c when I would leave for work. Coming back, cranking up the temp to 21-22c it was back at that temp within 30mins. So basically with the water heater. When you turn off the heater for those LONG periods you are now trying to heat up a MASSIVE amount of cold water. I would instead of totally turning off the heater 8-10 hrs at a time. Change it to run smaller time slots even just 10-15mins every hour to maintain a little heat. Your 4am warm up with in turn will run less .

Two things I would like to point out. This is a great video and your step by step install is pretty much spot on and easy to follow. I'm an electrician by trade and now work for an engineering firm so this is just me being me. #1 the metal box needs to be grounded. It's not clear to me that you connected the ground wire to the metal box. Remember the metal flex only covers the NM cable inside and can't be considered as a ground. #2 the 4watts that the shelly device and coil pulls doesn't have to be added to the final calculation as you wired them to the water heater circuit. The sense device shows you the entire circuit as one load. I also use the sense device and it has saved me a ton. Not sure if you have a pool but if you do the variable speed pump is also a great saver of electricity. It accounts for over 18% of my usage when if was a normal pump motor. I just changed it out and waiting for the sense device to find it again. Can't wait to see what it accounts for now that its a variable speed motor.

Great video once again, thanks. You're so lucky having such a low electricity price. Mine is more than double that in my country. So makes this sort of project even more beneficial. A few comments: 1. Consider using an approved type plastic box instead of the metal one. 2. Leave the original wiring as is, so that if you ever want to remove the contactor box (say you move house) you can reconnect the wires to the water heater and everything is back as it was. 3. Consider adding an appropriately rated "by-pass" switch on the box. That way if anything goes wrong with the contactor or controller you can switch the supply straight to the water heater and save a lot of user complaints. 4. Some electricity supply companies offer a lower "night rate" tarrif. If this is available, and your water heater has enough capacity, then you can save even more by only heating your water at night. You need to have a hgh enough capacity to ensure your water does not run cold during the day. I do this and it saves me a lot of money.

For those with second homes, cabins, whatever this would be especially useful. I'm sure the project is fun but if a consumer could buy a smart circuit breaker (that is good quality) it may have a higher adoption rate.

Nice video Rob, I'd suggest 3 improvements. 1. ground the metal box to make is safe should a hot wire make contact with it in the box and label the box to indicate that it has mains electricity inside 2. have a power-on indication light on the outside of the box 3. have a manual switch on the box door in case of failure of the Shelly/homeAssistant/automation

Wanted to thank you Rob, as based on this concept I built something very similar and now power my hot water via solar and 9 days out of 10 no longer pay for the power most of the time. Furthermore I added a Ecowitt thermometer (external) which via homeassistant turns on the switch/relay to heat the water during off peak (at night) on the days that it does not heat via solar power during the day. The same switch/relay turns on/off based on solar production during the day until the thermo in the tank turns off as the water is fully heated. I knew all this was possible, yet your video gave me the confidence to make it all happen!

Hi Rob. I installed a 30 amp relay on my geyser aka water heater in February and soon after that, got a Shelly EM connected to my main power line with the second CT clamp onto the water heater line. HA turns my water heater on at 6pm and turns it off at 9pm every day. I am also averaging about 6kwh per day. I am very amazed at the heat retention of these water heaters. I was able to take a hot shower at 1pm the next day - 16 hours after turn off - and the water was still very warm, so clearly my water heater isn't working as hard as I had thought to keep the water hot, so I have now turned off the automation so that I can compare. Unfortunately, we have had quite a few rolling backouts, so my data isn't complete, but I hope to gather better data over the next week or two (hopefully no rolling backouts to interrupt this test).

About a year ago I started purchasing some of the things I'd need to do a project like this... But then yeah to replace my water heater. We went with a heat exchanger water heater for the new one, which saves a bunch of energy, but it also has a very fancy touchscreen interface and WiFi connectivity. So I was able to schedule different temperatures and on/off timed completely in-unit. It's pretty sweet, and these new heat exchanger water heaters save so much energy that they pay for themselves in a few years of use.

Hi, I automated the heater about 2 years ago. The main reason is that Hydro Quebec has high rates in peak hours at about $.4 per kW and $0.04 during off peak. My calculation was to save about $100-200 per year. But eventually I removed it. In my family of four people (kids 12 & 14 y.o.) we had a collisions, when the washer and dishwasher used hotwater so the person may not have enough hot water to get a shower. I think, In general in North America the luxury of having a hot water at any moment reliably is overcome the benefits of savings $100-200 per year.

It is totally worth it. This is something I wanted to do 2 years ago. Now I am even motivated more to do it as soon as possible

I use a small 35 L water heater with a standard electric plug so it was easy to make smart. Most things that draw current in standby I automatically turn off after 10 seconds in standby and activate with my wall mounted light buttons. I turn on my fan automatically when my fire place is used. Everything is automated in my house 😃 Saving money is a bonus.

I'd love to see a video on the impact that insulation has on energy savings. If you put some heavy duty insulation with a high R value, that should reduce the time that the element actually needs to be on doing the heating.

This. So good, so clear, and so safe. Thanks Rob and I can't believe how much you saved here!!

This video was super clear and I really appreciate it. I automated my water heater this way over the weekend. I couldn't have done it without you. One thing that didn't show up in the video is what this sounds like. I bought a "Holdwell 45GG20AG 2 Pole 40 Amp 240V Coil Definite Purpose Air Conditioner Contactor" for my project and I discovered that it makes quite a loud CLACK when it engages or disengages. My hot water heater is in the basement and it's quite audible on the ground floor. I'm not sure if all contactors make such a loud sound or whether mine is unusual (or even possibly not right). In my case, my guest bedroom is down in the basement and I'm worried about the loud pop at 5:00am waking my guests. (I might have to just leave the hot water heater on when I have guests staying in that bedroom). I have no idea if this is common, and whether there's a quieter alternative. Depending on where in the house your hot water heater is (especially if you're in an apartment or condo) this might matter. Anyways, many thanks for doing this! I wouldn't have had the confidence to tackle this job without your video.

Wondering if the hot and cold cycles you have an increased risk of things like legionella growing in the water heater?

Be careful on the temperature of the hot water. You need to be sure it's hot enough to kill or prevent bacteria growth. Might want to use a temperature relay on the tank to monitor it's temperature. Otherwise, you might get your family sick. BTW : I live in Quebec and just like the US, our heater is 24/7. I have a Giant Cascade water heater, it have 3 heater instead of 1 or 2. The 3rd is a lower wattage and will keep water hot when you only use a little or to keep temperature steady when not in use, instead of turning the large heater on/off and overheating. It's better for everyone like that. You should also consider "isolating" your water heater better. Your garage might get cold. I am sure long rung it's better.

Great project! An air-source heat pump water heater will use a lot less energy than a standard electric resistance water heater, will also replace energy use of a basement dehumidifier if you use one, and some states or utilities have rebates for them. Some newer ones have wifi that could be integrated with home automation controls. I control my 2010-era GE HPWH with a tasmota single channel relay board and a resistor in series with the tank temperature sensor (thermistor). As I have solar & batteries with the house mostly off the grid, my control is different than you explained. The added resistance (relay open) tells the water heater that the water is cooler than it really is, so it will run then (during the day, when my controls see there is extra solar available to use). This heats the water to a higher temperature (up to 160F), and stores thermal energy like a battery. A thermostatic tempering valve limits the output water temperature to the house to about 120F. When the relay is closed (normally closed contact), the heater runs at it's normal temperature setpoint of 116F, which is typically already met, so it doesn't use any power from the house batteries at night.

Excellent vid. I had this done a couple years ago to smart a 240V pool pump using a contactor and a Kasa smart switch. Well worth the money.

The main reason for the mid-week daily energy saving is the hot water cools over time. When power is continuously applied the water heater ends up in a cycle of element on until water hot, water temp slowly drops, element turns on until water hot, water temp slowly drops, element turns on … This will happen even if no water is drawn from the tank. By using a timer to only heat water just before it’s needed, those regular but wasteful ‘back up to temp just in case’ boosts don’t happen.

thanks for info. I did similar accept getting around the shelly. I used a 120v contactor. I had existing plugin wifi auttomation adapter (15$ for 2) that supports google home. great part is its simple just a plug ub to a power strip. If it fails simply remove automation adapter and plug into outlet. The 120v will fire the 40a contactor (all in box and shielded), and its just a plain old WH. Works great and can schedule. I may add raspberrry pi to home just to control it to remove internet requirement, but also works from phone app. cheers

I did a similar project, but I used a RIB (Relay In a Box). I save extra $ by keeping my peak hourly usage down during the peak hours (M to F, 4 to 7). The hot water heater can distroy your peak hour usage since it is using something like 4 kWh while it's on. The electric utility company uses your highest single-hour peak during the peak hours during the month. So if you have even just one day where a single hour goes to 7 kWh when your norm is 4 kWh during the peak hours, this will cost you an additional 3 kWh peak demand charge @ about $20-$25 per kWh (with taxes and other charges), you would save at least $50 per month.

Where I live (Israel) it is common to have a solar heating system on the roof, so no need to heat the water during the sunny days of the year. To fully automate this, I used Sonoff TH16 + a temperature sensor that is attached to the outlet hot water pipe (from the outside). Then I could fully optimize the heating automation by adding the reading from that sensor, and activating heating only when temperature is below a certain threshold (for example: 40 degrees C.). Another condition to add to the automation is a toggle helper that indicates if you're on vacation, so no need to heat the water while the house is empty.

I have several (10+) automations for our HW heater in Homeassistant. I have halved our usage since I started. We have a Solar tank pre-feeding the main tank which is electrically heated. The automations have grown and grown and now take into account season, local climate, household members location, zone detection for people doing sports, guest and holiday modes and more. I now need to port it all into a Node-red flow for my sanity.

I already use a digital timer on my water heater and a mechanical timer on my irrigation system I think the Shelly relay will be a nice piece to modify both of these so that they can be run through automations thanks for the help with a Videos and the great information have a wonderful podcast

You need to insert an anti-shorting plastic bushing in the end of your cut BX cable, electrical tape is not up to code. Did you ground your new electrical box? If you did, I missed it in the video.

Here in the UK we are blessed with a company called Myenergi. They make a product called Eddi which controls the water heater in my 300L tank. From March to end October I don't pay for any hot water as the Eddi heats it every day from my excess solar. Then there is the Myenergi Zappi which does the same thing to charge my EV from excess solar! Then in the winter here November to mid March we have to rely on the grid and cheap rate tariffs (Not so cheap these days) to charge the solar batteries and charge the car. UK solar production swings from 1.5kWh per day on bad winter days up to 40kWh in the height of summer months. I have a 9kW solar system on the roof.

Thanks for the awesome video. Inspired me to take the plunge. While wiring everything up I ran into an issue. When switching the Shelly on, the contractor clicks and supplies voltage BUT the Shelly web interface freezes and after about 30 seconds the Shelly resets and the contractor disconnect then the web interface responds again with the Shelly in the off position. Have you ran into this? Do I have a defective Shelly? My hot water heater is 4500W just like your. Appreciate any assistance.

Great idea. I installed a Rheem heat pump HWT last year. It uses very little power. Around 1.5-2 Kwhrs/day depending on use. I use the heat pump only mode. I was surprised that it still uses 40 watts of power in vacation mode. This is just to power the display and the Wi-Fi. Having this on/off control feature may not be worth it in my case as that is not much power to save. Although the Shelly 1PM is drawing very little power in this application (4W), it is still being supplied by a 30A 240VAC circuit breaker. I would feel better with having either an inline 250v rated 1A fuse & holder or a 3A circuit breaker on either the L1 or N feed line from the contactor. This would be incase the Shelly fails internally. I would think the UL rating for the Shelly device would be limited to no more than a 15A circuit breaker supply. It is interesting that this is not mentioned anywhere in their wiring documentation.

What about those of us i the great white north with gas water heaters? I know it’s a big part of my gas bill, I wonder if there is a smart thermostat for hot water heaters…

Rob, thanks for the informative video and participating in the challenge.

You understood the assignment. Very in depth and incredible results

IMPORTANT The biggest gain is not the automation itself, it is automation in combination with kWh price per hour. Then you warm your water during cheap hours and prevent it from heating in the expensive hours, also enough size of the vessel is needed. Having the water heater in the house is also good cause every lost degree of temperature then goes out in the house and is not lost. In Sweden we some hours have as low as sub $0,01 per kWh but also now after Russias war on Ukraine we have up to as much as $1 in rare cases.

I have a NG waterheater . I take one shower a week . I wash clothes once every 2 weeks and do a house cleaning every 2 weeks . So i put my water heater in vacation mode for most of the time . I turn on for the shower and wash clothes or house cleaning once a week . I turn back to vacation mode just before i take my shower . We are just so wasteful as a society . 24/7 hot water is so unessasary .

Great video, really helpful to see the specs for each component. For some reason the Shelly 1PM is currently unavailable on Amazon canada. Could I use the Shelly 1, with appropriate change to the wiring?

This is a great idea, the one elephant in the room though is the vast majority of people probably are not skilled enough to do this and this is a relatively low skill job, so an electrician cost will definitely add to the cost. That said if I used electricity to heat water, here in California where you multiple that electricity cost by about 3, this would be a good deal of savings, although a hybrid water heater probably could do something similar if not better... that said I have natural gas for my water heater and recently switched to a tankless water heater, and I am handy enough to do the work so the cost between that and a traditional water heater wasn't terribly much.

In the north east we don’t see a lot of electric water heaters most tend to be natural gas or propane. I switched to a tankless water heater some years back and love it as there’s just 2 of us and we don’t use much hot water so only heating what we need, when we need it is great. The automation idea is nice as long as you account for the re-heat time on the front end, and don’t have much need throughout the day, but there are much higher efficiency water heaters that could be a better saving. There are also contractors and solid state relays which don’t have to use line voltage; I’m an electrician and have gotten into automating some years back and tend to run everything off 12 controllers and solid state relays which can keep up with decent amp loads and have the added benefit of bringing down control voltages to low voltage levels which enables more control options. I will agree with another electric and hope you added an insulation bushing to your BX/MC cable before putting it through you elbow and that you need to ground the box itself; NEC also doesn’t allow for extra openings in boxes, and they make plugs that you can just pop in to close the knock out you popped out. You also should probably have chosen a box with a screw on cover as kids can open things up and the box you used looked to simply have a hindered door, though I may be wrong. Automation has come a long way with relay panels,or load centers actually being a practice solution for controlling multiple circuits without needing individual stop gap fixes or solutions in line; you see this more in the commercial and industrial sectors then in residential but they’re trickling in. Sadly the residential home integration ecosystem still tends to be home built options more than easy plug in fixes, at least regarding hardwired appliances.

There’s also natural gas tankless water heaters that only come on when hot water is needed. They work great. If your building a new house or replacing a water heater and have options for natural gas or a large propane tank they are a great choice. Especially if gas/propane is cheaper than electricity.

I have been using a contactor combined with a Sonoff basic flashed with Esphome and integrated with Home Assistant to manage and control my water heater for the past two years. :)

I hooked up a yolink smart plug to the recirc pump. It turns on the hot water recirc pump. For five minutes when i hit the yolink fob button. Saves running the water until hot at the faucet. Helps save money and we have irregular schedules. Saves running recirc pump on hot water for unnecessary time.

I'm using a contactor to automate my pool in home assistant. Hadn't thought of using it for the water heater. Thanks for the tip!

Just did this project at what will be a rental and then learned of the legionella issue the next day. I think the ideal solution is the hight temp thermostat setting with the use of thermostatic mixing valves at point of use to safeguard against burns in an automatic manner. UV could also be used as a sanitizer but that's be more electricity and bulb replacements with the need of negating buildup on the bulb.

Did you consider adding more insulation around the tank to reduce the energy loss that way? Are your hot water pipes insulated throughout your home?

We have a heat pump water heater (the one in your thumbnail actually). It uses less than half that power on a heavy usage day. And that's in the spring. It uses even less in the summer when there's more free heat available. It also automates all of this for you. You pay more up front, but it pays off pretty quickly.

I did this a few years ago and I saw a huge diff in my electric bill. Mine has a push button to manually turning on/off. I also have a display screen which shows the time and date and the tank temp and the display screen only turn on when there is motion. Next I have a temp sensor and a flow sensor. late at night if the hot water is running for more than 3 min it indicate someone taking a showing so the hot water tank will turn on and remain on for 5 more min until the hot water stop running.

Aquanta is also something but more expensive upfront and to be honest doesn't really provide additional smart info that they claim such as tank hot water capacity. Also their scheduling app is kind of hard to program well. Another unexplained advantage of putting your water heater on a smart switch is you can program it to turn off whenever your hvac triggers on therefore greatly reducing your demand charge assuming you setup a demand based rate plan with your electric provider. In this case you can also install an EasyStart to your home HVAC to drastically reduce inrush demand when the compressor switches on. So basically staggering the 2 biggest electricity demand devices in your home so they don't occur at the same time and reducing the huge inrush current required by your heat pump or air conditioner.

It will be great to see what your energy savings is with the tank needing to pull the water up to temp after having been off for the preceding hours. A insulation blanket could help hold temps up between on times.

Heat Pump water heater would not only save huge power, but also air condition and dehumidify your garage. wins all around, and I think they come with smart features as well. $1600, sure, but I think well worth it. We have gas powered ones up north, and I think heat pump is still cheaper to run.

Here in the UK it is normal to have the water heating integrated with the central heating so by replacing the traditional boiler controls with a Sonoff 4Chan I could manage both the CH and the HW using Node Red - one effect of that was that I found I could eliminate not only most of the scheduled water heating periods but also the HW temperature depending on whether it is a shower or bath that would be required. At the moment on weekdays I have on average 1hr HW heating to cater for pre work shower and at all other times by asking Alexa the water temperature and then if necessary ask for a shower/bath to be provided she will then typically respond within 15-20 minutes to say the water is now ready. The only other factor is an occasional heating of the water to 65C to control any danger of bacteria build up. Power usage has dropped greatly especially as we are currently paying around 30-35c per KWh.

Ghosh, I wish I saw this a few weeks ago, the US water system is/was a complete mystery to me and wanted it to be automated. Now I can.

Very thorough Rob! I still need to try out some Shelley devices.

Flexing with the ti-83!! 👌

A couple of years ago we moved from an electric tank water heater to an on-demand gas tankless. At the time we had 8 people in the house and we cut about $40/month of electricity usage out. It was replaced by a gas bill, but it wasn't $40/month (more like $30ish once you included their base fee) we've also since gone gas for our stovetop since I prefer cooking over gas. Another benefit is that during a long term power outage (hurricane), I can easily just hook up the water heater to a small battery bank or UPS and we get hot water for days as long as we have natural gas still flowing to the house. Not for everyone and not everyone has natural gas available, but it is another option for potential savings. We have considered moving our electric dryer potentially to a gas unit as well. I will say that your return on investment will be a lot quicker than ours will be. We didn't do it just for the money savings. Unlimited hot water whenever you want it is really nice :)

Hi Rob, Your contactor solution would also work for those on a well pump. I asked a plumber about installing the Moen Flo device and he said that's great for the water traveling out of the water tank into the house, but what if a leak occurs in your tank or before... Your p-stat will detect low pressure and your well pump will be running bringing in water. I can install a contactor as you show to the supply power for the well pump pressure-stat!

great project, I was looking for a way to automate my well pump (runs on 240v), thanks for sharing

Is there a concern for Legionellae with the long down time periods?

Jasco makes a 240v Z-wave switch that I want to use for my 80 gallon water heater. That switch has a power meter built in and a manual on/off button on the switch - just in case HA goes down.

You got a new subscriber I did the same project ordering everything from your list. My bill in Hawaii 400$ month, I hope I see it dropping.

you have a ton of interesting projects but for an earth day project this is pretty amazing. while not a tremendous savings over short periods of time, it it clearly a large savings over a long time. and also... who would have thought to automate their water heater!? i will definitely be 'stealing' this one in the near future. awesome job yet again!

7 day purpose built water heater timers can be purchased. No need to fiddle around making one unless you just want to. Timers like the Intermatic EH40 are right around $100

As a follow up on the Water Heater project, my version which has the same Shelly 1PM UL and an Eaton 240v contactor has been operational for a couple of weeks. But there's a glitch, the contactor has an inductive "kick" when power is switched off due to the collapsing magnetic field, the result is there's enough energy to arc the contacts of the Shelly relay and also knocks the Shelly off line and it reboots. In discussion over on the official Shelly reddit pages it appears that a MOV or metal oxide varister wired across the terminals of the contactor relay coil should cure the problem. It has to be rated at somewhat above the voltage of the coil, but it should shunt the kick to make it mostly harmless. I ordered one from DigiKey and will get it installed when it comes in the mail. Will let you know.

I used to do this. But I don't have a strict or remotely predictive schedule. So it just ended up bothering me and being on 24/7 again. I bought a solar water heater instead. It's great.

You could add a water flow sensor to the cold water input side of the hot water heater and a DS18B20 temperature sensor to the hot water tank and program them to activate the hot water heater in time slots that are normally programmed as “OFF”. Like… if the unit is off, the flow sensor is sensing flow and the hot water temperature is below a pre-determined temperature, turn the hot water heater on, BUT if the flow meter is sensing flow longer than X amount of minutes, it may be a water leak so turn off the main water valve and send a notification. Also add a flow sensor to the city water water line also and program that also.

What we frankly should do... like a lot of countries... is having centrally heated water... because that is sooooooo much more efficient, especially if using the heated water from powerplants and cycling it.

I have a different hot water system set-up so I won't go into that. All I wanted to say or ask was, how much effect, would wrapping your hot water storage in additional insulation, have? Obviously if you're keeping it off for periods, the benefit would be less but it would still be interesting to understand.

I’ve already done this in the U.K. using a Sonoff basic (LAN Mode simple switch) from AliExpress. Suspect this is cheaper in the U.K. Added advantage that you can upgrade to a Sonoff TH10 and include a temperature sensor. I have mine tunnelled into foam around the hot water tank. Upper limit is 80°C though so not at the top of the tank. Current TH10 includes graphing function (of temperature/humidity) and a LAN mode so I think I will upgrade to this.

Another thing you could do is turn down the thermostat on your hot water tank. The common default setting is 140 degrees Fahrenheit. The EPA recommends 120 degrees because it’s hot enough to keep diseases at bay, it’s not hot enough to cause scalding, it will supply enough hot water for most small families and is relatively energy-efficient.

I built my smart switch following the instructions in the video. However, shelly device sometimes goes offline after triggering the relay and I have to flip my breaker to restart the device. I think you absolutely have to install RC snubber to avoid voltage surge during switching, a relay is an inductive load.

Yeah... I'd pay the $66 a year to be able to wash dishes, do laundry, and have access to hot water at times besides 6 AM and 6 PM.... plus having a background in real estate, I've seen A LOT of water heaters that had to be replaced do to sellers turning them off and on excessively. I'm not a water heater expert, but I know that flipping at least some of them off and on isn't good.

Have you considered switching to a heat pump water heater? I've switched and the efficiency is incredible.

Good information. I turn my hot water heater off just Before my shower. Plenty of hot water for a shower and there is no advantage in reheating the water just before turning it off for the day.

120 volts will kill you. It is very unlikely to ever get shocked or electrocuted by 240v since you would need to touch both wires as the exact same time. Touching the first, 120v, hot wire will likely throw you off or lock you to it with 120v before you ever have a chance to touch the second wire. People who say they have been shocked by 240v, were probably shocked by 120v at a circuit with two 120v, out-of-phase lines. Most people underestimate the danger of 120v. The lethality is all in your level of conductivity and how well grounded you are.

Here in the uk pence per kWh is more like 37pence, so you are getting it cheap. In this country such automation is a no brainer, I have time switches and contractors all over my house.

Good video! Probably more of a money saver going tankless in warmer states. Here in MN that really isnt an option. The btu needed to raise the ground water temp is absolutely ridiculous.

I had an electric hybrid water heater installed. It heats water by heat pump. It reduces energy consumption to heat water by 3/4s.

Would you be willing to post a list of node-red nodes you currently use?

cool project. I like the idea but in reality heat pump water heaters are the future. It would work perfectly in a Florida garage. I installed one in my basement and through the app it uses about 1.5KWh per day. The app also has automation scheduling to turn it off/on whenever you want.

I'm not an expert but shouldn't he connect the ground wires to the metal box?

Can’t wait for an episode for automating swim pool equipments which is another big energy monster

I went the DIY route for my heating. There's a pi that acts as home server and router, so I wired it up to a relay in the thermostat line. It controls the heating based on the presence of my phone on the network. When my phone leaves the house, and by implication I am not home, the heating turns off. Doesn't save much though, because the climate here only gets low enough to need the heating for maybe two months a year.

Great idea to work with the existing water heater. When it’s time to replace it I would consider purchasing an instant hot water system which means it only heats up the water when you are using it and it only heats up a small body of water as it goes through the heat exchanger.

I've thought about this type of automation a few times, but I have a gas water heater. So I wouldn't need the high voltage relay, and instead would need a new power source for the Shelley and somehow interface with the electronic gas controls. I'm not quite ready to mess with gas appliances yet...

I bought a much better quality (twice the cost) water heater, 30 years ago (still working, no leaks), one with better insulation. It's sitting on an insulated pad, and has an extra blanket of insulation. Pipes have anti siphon twists. Even after a 12h power failure, water is still very hot. Turning off the power would be silly given my circumstances. Point being, better insulation is another approach. Arguably better.

Great video, looks like a cool project. I already have a manual timer on mine called the little gray box. I Ended up using that to manually control the on off schedule. But I like your ideas better

I think my post got killed because it had a link in it, but rheem sells a wifi upgrade module that works with many of their Gas and Electric water heaters that lets you control the temp and when it is on. There is also a cloud integration for it already in Home Assistant. Nothing beats local control but the addon avoids touching any of the high voltage electrical.

This was fantastic and so easy to understand!! I just happened across this and so happy I did !!! Now I'm subscribed and will check the other videos. Thanks so much !!

Just subscribed....looking to set up a second hot water heater that runs just when i say so to optimize the benefit of my solar panels! Thanks

Let's see: I can waste hours sourcing and putting this makeshift water heater device together, or for about 2/3rds the price (on Amazon and occasionally on eBay) I can get a DEWENWILS (it used to be Wion a while ago) 240V Wi-Fi switch. Hmmmm. I really need to think about this. Glad I installed 4 of these (2 HW heaters, plus pool and sprinkler pumps) a bunch of years ago.

Why not replace the unit with a tankless unit and a hot water circulator that is on a motion sensor or hot buttons? That would further save gallons of water being dumped down the drain until the shower/faucets are hot. Person walks in to the bathroom or hits a "heat" button by a main sink etc, a minute or so and the water is cycled through the tankless. Once the water starts the tankless heats what you need near infinitely, then shuts off along with the pump after a certain amount of time. Insulate the hot lines to retain heat and spend even less.

I got tired of the thermostats on the elements flaking out. Mine now has an esp32, mqtt & a pair of forced-air cooled SSRs. The 155F factory cut-off is still in place, just in case.

Not a single mention of maintaining temperature to avoid bacteria growth? Our water heaters are thermostat regulated and it is recommended to keep the water at 70C. Since it is thermostat regulated it mostly turn on when hot water is used and cold water enters the tank and needs to be heated. Less hot water usage= energy saving. (And also not having an ancient water heater that's poorly insulated. Is is actually better to maintain a higher temperature and mix in more cold water at the hot water exit.

I'm from Australia and basically you're hitting a fly with a baseball bat! Here in Oz, we have timers that fit in a fuse and do the same thing that you just did

The water temperature needs to stay warmer enough to prevent bacterial proliferation around 115F (45C).

My heater has this functions for full heat programmable from start. But what it also have programmable, is a minimum temperature on the water. What this does is two things, firstly you will have hot water for other things like washing your hands and whatever you use it for between the showers, but also which I believe is to save electricity is to not having to warm up the water from scratch when it is shower time. This is of course more important in Sweden where the water comes in at 4 degrees centigrade in the winter. However, it would be interesting to put a thermometer sensor in the heater to be able to automate the temperature of the water between the shower periods. Maybe it is more efficient the heat the water with shorter bursts between shower periods?

Great vid, but I'm surprised you don't have solar. We have panels on the roof & the surplus heats the water. Even here in the UK we've switched off the gas heating for the water and rely totally on solar surplus already!