1 00:00:00,060 --> 00:00:03,659 Take a look at this label on this 40 gallon  electric water heater. 2 00:00:03,659 --> 00:00:05,752 It lists three wattages: 3 00:00:05,752 --> 00:00:07,968 Upper is 4500W. 4 00:00:07,968 --> 00:00:10,310 Lower is also 4500W. 5 00:00:10,310 --> 00:00:12,717 And of course that totals… 6 00:00:12,717 --> 00:00:14,871 4500 wa - whatt? 7 00:00:14,871 --> 00:00:16,206 Who wrote this? 8 00:00:16,206 --> 00:00:17,926 Actually, that’s not a mistake. 9 00:00:17,926 --> 00:00:22,030 You’ll find similar labels on most conventional electric water heaters. 10 00:00:22,030 --> 00:00:29,879 Oh and, by the way, that second listed wattage is what it would run at if hooked up to a 208V electrical supply rather than 240, 11 00:00:29,879 --> 00:00:33,515 which you’ll usually find in office and large apartment buildings. 12 00:00:33,515 --> 00:00:38,722 Using Ohm’s law we can determine that this thing’s heating element has a resistance of 12.8 ohms, 13 00:00:38,722 --> 00:00:44,277 which at 240V would draw 18.75 amps and thus 4500 watts 14 00:00:44,277 --> 00:00:51,064 but at 208v it would only draw 16.25 amps which works out to 3380W. 15 00:00:51,064 --> 00:00:52,838 Math is fun! 16 00:00:52,838 --> 00:00:56,891 Anyway, how can those two numbers add up to themselves? 17 00:00:56,891 --> 00:00:59,972 This label would suggest 2+2 is 2. 18 00:00:59,972 --> 00:01:03,291 And I’m pretty confident that’s wrong. 19 00:01:03,291 --> 00:01:10,056 Well, you might have guessed by the labels “upper” and “lower” that there are two separate heating elements in the water heater - 20 00:01:10,056 --> 00:01:13,620 indeed there are, and they’re both the same power rating. 21 00:01:13,620 --> 00:01:17,611 The reason for this silly math has to do with the thermostats. 22 00:01:17,611 --> 00:01:19,629 Yeah, there’s two of those, too. 23 00:01:19,629 --> 00:01:27,647 But they’re cleverly interlocked in a way that not only prevents them from running at the same time which would overload the electrical supply 24 00:01:27,647 --> 00:01:32,340 but also makes the operation  of the water heater smarter and more effective. 25 00:01:32,940 --> 00:01:36,339 A water heater like this is an extremely simple device. 26 00:01:36,339 --> 00:01:42,797 It’s really just an exceptionally well-insulated cylindrical tank of water with a few holes in it. 27 00:01:42,797 --> 00:01:45,607 Up top there are holes to let water in and out. 28 00:01:45,607 --> 00:01:50,177 Down below is another hole with a spigot to let you flush out the tank periodically, 29 00:01:50,177 --> 00:01:54,755 and then there are two holes in the sides of the tank under these covers. 30 00:01:54,755 --> 00:02:00,707 The heating elements stick into the tank and thus into the water through those holes and when power is run through them 31 00:02:00,707 --> 00:02:02,552 they get real hot. 32 00:02:02,552 --> 00:02:04,925 This is really just an overgrown kettle. 33 00:02:04,925 --> 00:02:12,192 Now, there are actually two more holes in the tank, one of which leads to the temperature/pressure safety valve up top. 34 00:02:12,192 --> 00:02:17,136 Heating water makes it expand slightly which increases the pressure inside the tank. 35 00:02:17,136 --> 00:02:19,567 Ordinarily this isn’t a problem. 36 00:02:19,567 --> 00:02:25,640 The tank may seem like a sealed pressure vessel but it’s still connected to the rest of your plumbing. 37 00:02:25,640 --> 00:02:33,907 As the water inside expands, some water will simply move out of the tank by pushing the water in the supply line backwards. 38 00:02:33,907 --> 00:02:38,700 However, if you have an entirely closed plumbing system with backflow prevention, 39 00:02:39,360 --> 00:02:45,437 then that won’t be possible so you probably  have an expansion tank installed with your water heater. 40 00:02:45,437 --> 00:02:47,140 At least I hope so. 41 00:02:47,140 --> 00:02:54,802 But anyway if for whatever reason pressure starts building up too high in the tank and/or the water inside is getting too hot 42 00:02:54,802 --> 00:02:59,981 then this valve will pop open, releasing that pressure and  spraying hot water onto the floor, 43 00:02:59,981 --> 00:03:03,916 and you will have a very bad day but at least the water heater didn’t explode. 44 00:03:03,916 --> 00:03:05,341 That’s nice. 45 00:03:05,341 --> 00:03:08,956 And the final hole in the tank is one many people overlook. 46 00:03:08,956 --> 00:03:15,739 Because the tank is made of steel which, I don’t know if you’ve heard but doesn’t really like to be in prolonged contact with water, 47 00:03:15,739 --> 00:03:24,528 a sacrificial anode rod often made of aluminum or magnesium pokes down into the water to take the corrosion bullet for the rest of the tank 48 00:03:24,528 --> 00:03:25,740 and keep it from rusting. 49 00:03:26,280 --> 00:03:32,047 The top of that rod lives buried underneath the foam insulation that's underneath this plug, 50 00:03:32,047 --> 00:03:34,833 and it can actually be replaced! 51 00:03:34,833 --> 00:03:38,880 If you do that regularly, it can extend the life of your water heater significantly. 52 00:03:39,480 --> 00:03:42,584 But almost nobody does that, including me. 53 00:03:42,584 --> 00:03:43,860 Yay laziness! 54 00:03:44,460 --> 00:03:46,676 But this isn’t a home improvement channel… 55 00:03:46,676 --> 00:03:52,247 So what's so special about this water heater that’s making me make a video about it? 56 00:03:52,247 --> 00:03:56,777 Well, earlier I said the thermostats make it smarter and more effective. 57 00:03:56,777 --> 00:03:58,773 Allow me to explain. 58 00:03:58,773 --> 00:04:02,522 Notice that even though this is a 40 gallon water heater, 59 00:04:02,522 --> 00:04:06,963 its rated capacity is somehow 53 gallons. 60 00:04:06,963 --> 00:04:10,883 Where did it magic 13 extra gallons from? 61 00:04:10,883 --> 00:04:17,981 Well, I suppose we can let water out of the tank while also heating incoming water, can’t we? 62 00:04:17,981 --> 00:04:20,880 Yes, but there’s more to it than just that. 63 00:04:21,420 --> 00:04:27,034 First, how exactly does the water flow into and out of this tank? 64 00:04:27,034 --> 00:04:29,170 Both pipes are at the top, 65 00:04:29,170 --> 00:04:35,846 but the incoming water supply pipe attaches to a dip tube that travels all the way down to the bottom of the tank - 66 00:04:35,846 --> 00:04:41,100 meaning cold water enters the tank from below and pushes hot water out the top. 67 00:04:41,820 --> 00:04:44,875 We can actually observe this with the thermal camera. 68 00:04:44,875 --> 00:04:50,519 Right now the tank has a fairly uniform temperature, just a few degrees above ambient. 69 00:04:50,519 --> 00:04:54,172 But when I open a tap and start using its hot water, 70 00:04:54,172 --> 00:04:58,588 we see that it’s only getting colder at the bottom of the tank. 71 00:04:58,588 --> 00:05:06,004 And here’s something pretty fascinating about water: so long as you reduce turbulence and keep things relatively still, 72 00:05:06,004 --> 00:05:10,448 the hot and cold water inside the tank doesn’t mix. 73 00:05:10,448 --> 00:05:12,451 Like, at all. 74 00:05:12,451 --> 00:05:17,858 You can see that as I continue using hot water, the region that’s cold is getting bigger, 75 00:05:17,858 --> 00:05:22,260 but the hot parts up top are still just as hot as they were when I started. 76 00:05:22,920 --> 00:05:27,177 This happens because hot water is less dense than cold water, 77 00:05:27,177 --> 00:05:35,760 so in effect it “floats” to the top of the tank, and as a result a surprisingly sharp boundary between hot and cold is maintained.   78 00:05:36,480 --> 00:05:42,435 Now you might think that over time that boundary layer will disappear and the water will mix together but 79 00:05:42,435 --> 00:05:44,573 for the most part it doesn’t. 80 00:05:44,573 --> 00:05:51,244 Any water that cools down inside the tank (like for instance the water clinging to the slightly cooler tank walls) 81 00:05:51,244 --> 00:05:57,788 becomes more dense and simply sinks to the bottom, piling in with the rest of the cold water. 82 00:05:57,788 --> 00:06:04,483 After a very long time without adding heat energy to the tank  the remaining hot water does start to cool down, 83 00:06:04,483 --> 00:06:07,491 but it takes a lot longer than you’d think. 84 00:06:07,491 --> 00:06:09,988 Like, the better part of a day. 85 00:06:09,988 --> 00:06:11,146 It’s pretty wild. 86 00:06:11,400 --> 00:06:16,423 This thermal stratification combined with how we fill the tank from the bottom-up 87 00:06:16,423 --> 00:06:18,731 turns out to be really useful. 88 00:06:18,731 --> 00:06:24,218 Remember that we have two heating elements sticking into the tank at two different heights. 89 00:06:24,218 --> 00:06:32,342 As you continue using hot water, eventually the cold/hot water boundary reaches the bottom heating element and its thermostat,   90 00:06:32,342 --> 00:06:37,904 kicking that element on so it can start  working to heat the water as it flows into the tank. 91 00:06:37,904 --> 00:06:43,469 [sound of water trickling in pipes] 92 00:06:43,469 --> 00:06:47,512 [hissing noise from the element starts] 93 00:06:47,512 --> 00:06:55,406 Now, 4500 watts may seem like a lot of power, but in the context of water heating it really isn’t. 94 00:06:55,406 --> 00:06:59,460 It takes gobs of energy to heat water. 95 00:06:59,460 --> 00:07:09,150 At most the water heater can put 4500 joules into the water per second, or 1075.5 gram calories per second. 96 00:07:09,150 --> 00:07:15,312 On a cold winter day the water entering the tank might be 10 degrees Celsius if we’re lucky, 97 00:07:15,312 --> 00:07:19,890 and our target temperature is generally around 50 degrees Celsius. 98 00:07:19,890 --> 00:07:23,900 So we need to attain a 40 degree temperature rise. 99 00:07:23,900 --> 00:07:30,039 If we divide the gram calories we have every second by the 40  degrees we need to increase in temperature, 100 00:07:30,039 --> 00:07:37,854 we find that we can only heat 26.9 milliliters of  water per second, or about 1.6 liters per minute. 101 00:07:38,280 --> 00:07:45,199 That’s not too bad, really, but the lowest flow shower heads you’ll generally find here are 1.5 gallons per minute, 102 00:07:45,199 --> 00:07:47,040 and they may go as high as 2.5. 103 00:07:47,940 --> 00:07:53,160 Sticking with the smaller number, that’s nearly 5.7 liters per minute of flow.   104 00:07:53,880 --> 00:07:57,318 Of course most people temper hot water with a bit of cold water 105 00:07:57,318 --> 00:08:02,055 so we might only have 4 liters leaving the hot water tank every minute 106 00:08:02,055 --> 00:08:06,335 but that’s still more than double what we can heat with 4500 watts. 107 00:08:06,335 --> 00:08:09,588 So we’re going to run out of hot water eventually. 108 00:08:09,588 --> 00:08:11,160 There’s just no getting around that. 109 00:08:11,700 --> 00:08:15,173 Even if we try and heat the water as it enters the tank, 110 00:08:15,173 --> 00:08:22,740 the water is simply moving out too quickly and it won’t reach the target temperature by the time we’ve used up the hot water already in it. 111 00:08:23,460 --> 00:08:28,776 But, remember there’s a second heating element above the one at the bottom. 112 00:08:28,776 --> 00:08:30,509 It isn’t any more powerful 113 00:08:30,509 --> 00:08:36,298 but with a bit of strategy we can use it to chase the water as it leaves the tank. 114 00:08:36,298 --> 00:08:40,113 And that’s exactly what the water heater does. 115 00:08:40,113 --> 00:08:48,000 With our theoretical 4 liters per minute flow rate, the lower heating element will  only achieve about a 16 degree temperature rise. 116 00:08:48,540 --> 00:08:52,897 That's nowhere enough, but also that’s not nothing. 117 00:08:52,897 --> 00:08:55,380 So long as the lower element is turned on, 118 00:08:55,380 --> 00:09:00,153 in effect the bottom of the tank is filling up with 26 degree water 119 00:09:00,153 --> 00:09:01,920 rather than 10 degree water. 120 00:09:02,640 --> 00:09:06,720 And once that tepid water reaches the top element, 121 00:09:06,720 --> 00:09:12,191 well now its thermostat kicks in and switches the power output to itself. 122 00:09:12,191 --> 00:09:17,768 We have the same 4500 watts that we did before, but now it’s up here - 123 00:09:17,768 --> 00:09:21,292 working to heat the water we’ve already started heating. 124 00:09:21,301 --> 00:09:23,702 [hissy water heater sounds] 125 00:09:25,458 --> 00:09:27,723 [CLACK, hissing stops] 126 00:09:29,147 --> 00:09:34,065 [a new and louder hissing begins] 127 00:09:34,260 --> 00:09:39,734 We can still only achieve a 16 degree temperature  rise with 4 liters per minute of flow, 128 00:09:39,734 --> 00:09:42,641 but that’ll get us up to 42 degrees. 129 00:09:42,641 --> 00:09:46,496 Not exactly where we want to be, but still plenty hot. 130 00:09:46,496 --> 00:09:53,546 We will of course still run out of hot water - once the  top element kicks on the bottom switches off, 131 00:09:53,546 --> 00:09:59,221 so the water entering the tank is now truly cold and once it’s up near the top... 132 00:09:59,221 --> 00:10:00,898 well, game over. 133 00:10:00,898 --> 00:10:04,799 At best we’re getting 26 degree water out of the tank, now. 134 00:10:04,799 --> 00:10:15,420 But this strategy bought us some extra time with a limited power source simply by changing where we applied that power, and heating the same water twice. 135 00:10:16,200 --> 00:10:20,260 This is where we magicked 13 extra gallons from. 136 00:10:20,260 --> 00:10:30,117 4500 watts is 4500 joules per second, and that's 16.2 million joules per hour or 3.87 million gram calories. 137 00:10:30,117 --> 00:10:34,620 And lift 96.8 liters of water by 40 degrees celsius. 138 00:10:35,400 --> 00:10:43,393 So over an hour, this water heater can bring 25.5 gallons of cold water to our target temperature, 139 00:10:43,393 --> 00:10:46,860 and that is where this “1st hour rating” comes from. 140 00:10:47,580 --> 00:10:51,637 I reckon it’s only listed as 13 gallons over the true capacity 141 00:10:51,637 --> 00:10:58,270 since it was calculated using a 208V supply and assuming we start with freezing cold water. 142 00:10:58,270 --> 00:11:00,192 Quite conservative. 143 00:11:00,192 --> 00:11:09,394 In any case, this means that over an hour the energy it can  add to cold water plus the energy it has stored in 40 gallons of already hot water 144 00:11:09,394 --> 00:11:12,720 is the same as if you had 53 gallons in the first place. 145 00:11:13,440 --> 00:11:19,380 And on 240V like I have here it may be closer to, like 65 gallons. 146 00:11:19,380 --> 00:11:27,251 The strategy employed here is frankly genius, especially considering how simple this device is. 147 00:11:27,251 --> 00:11:31,076 All we have are two bog-standard thermostats. 148 00:11:31,076 --> 00:11:38,230 There are no electronics here, there’s no control scheme, it’s just a thermostat for each heating element. 149 00:11:38,230 --> 00:11:44,608 The only complication to the circuit design is that the top thermostat always takes priority. 150 00:11:44,608 --> 00:11:51,163 If that heating element is switched on, the thermostat breaks the circuit to the lower element to prevent it from running. 151 00:11:51,540 --> 00:11:55,931 Now, you might think this would cause some sort of operational conflict. 152 00:11:55,931 --> 00:12:01,728 What if we want the bottom thermostat to run but the top one happens to have kicked on? 153 00:12:02,537 --> 00:12:04,713 Well, think about this for a sec: 154 00:12:04,713 --> 00:12:10,881 because hot water stays at the top of the tank naturally, and we fill it with cold water comes in at the bottom, 155 00:12:12,156 --> 00:12:14,732 for the most part that just doesn't happen. 156 00:12:14,732 --> 00:12:17,559 In fact, top element rarely gets used at all. 157 00:12:17,559 --> 00:12:22,842 It basically only comes on after you have used up more than half of the water in the tank. 158 00:12:22,842 --> 00:12:27,865 If you don’t use at least that much, the bottom element will take care of things. 159 00:12:27,865 --> 00:12:31,260 Same goes for keeping the tank warm between uses. 160 00:12:31,260 --> 00:12:38,468 And with a low-flow shower head, 15 minutes in the shower is unlikely to use much more than 20 gallons of water. 161 00:12:38,468 --> 00:12:42,081 So, yeah, the top one just doesn't need to run. 162 00:12:42,081 --> 00:12:47,045 But if you do happen to use up all the hot water, or even just come close to that, 163 00:12:47,045 --> 00:12:52,203 well now the strategy of giving the top element priority helps us again. 164 00:12:52,203 --> 00:12:56,559 While we can of course use the bottom element alone to heat the water, 165 00:12:56,559 --> 00:13:00,294 after all the hot water it generates down there will float  up to the top, 166 00:13:00,294 --> 00:13:05,155 doing that means we have to heat the entire volume in one go. 167 00:13:05,155 --> 00:13:13,380 Whatever hot water it generates at the bottom has to travel through all the cold water on its way up to the top which will of course cool it down. 168 00:13:14,040 --> 00:13:18,780 Oh, by the way, I should mention that  whenever the elements are actively heating,   169 00:13:18,780 --> 00:13:26,377 there is some mixing and churning of the water going on inside the tank thanks to the convection currents that generates. 170 00:13:26,377 --> 00:13:28,920 You can see that happening here with this kettle. 171 00:13:29,520 --> 00:13:34,920 That’s how we can heat the entire tank of  water using what amounts to two hot sticks. 172 00:13:35,520 --> 00:13:41,077 Anyway, if we want to heat 40 gallons  of cold water by 40 degrees celsius, 173 00:13:41,077 --> 00:13:46,320 it’s gonna take over 6 million calories or about 7039 watt-hours.   174 00:13:47,040 --> 00:13:52,563 With 4500 watts to play with, that’s gonna take about an hour and a half. 175 00:13:52,563 --> 00:13:59,640 However, if we only send power to the top element, then in effect we only have to heat half of the water.   176 00:14:00,300 --> 00:14:06,882 We’ll still get some convection currents around the element, but we won’t be mixing all of the water together - 177 00:14:06,882 --> 00:14:09,479 the bottom of the tank will stay cold. 178 00:14:09,479 --> 00:14:18,771 So we’ll get the water in the top of the tank (which remember is what leaves first) up to our desired temperature in half the time. 179 00:14:18,771 --> 00:14:27,008 So even after completely running out of hot water, you’ll get truly hot water again after only 45 minutes or so. 180 00:14:27,008 --> 00:14:33,960 Only once that’s warm and “ready” will we send  power back down to the bottom element to heat up the rest. 181 00:14:34,620 --> 00:14:38,900 I know that I’m weird, but I think this is amazing! 182 00:14:38,900 --> 00:14:44,349 I only recently learned that there are two thermostats on the water heater. 183 00:14:44,349 --> 00:14:50,981 In hindsight it probably should have been a little more obvious since, y’know, there’s two identical covers on the front but 184 00:14:50,981 --> 00:14:57,120 I just assumed that was for cost cutting or something and thought there  was one thermostat controlling both elements.   185 00:14:58,200 --> 00:15:02,520 Well, OK I guess there still is,  technically, but… y’know what I mean. 186 00:15:02,520 --> 00:15:10,869 The simple physics of how hot water behaves in a tank allowed us to implement a very strategic method of heating it 187 00:15:10,869 --> 00:15:15,660 using nothing but a dip tube and two interlocked thermostats. 188 00:15:16,518 --> 00:15:20,756 Just doing that covers pretty much all possible concerns: 189 00:15:20,756 --> 00:15:29,643 how best to heat a cold tank for the fastest-possible hot water, how to chase it on its way out for some extra reserve capacity, 190 00:15:29,643 --> 00:15:35,784 and how to do both those things with a more reasonable amount of input power. 191 00:15:35,784 --> 00:15:38,280 And that’s what I call … neat! 192 00:15:40,800 --> 00:15:45,927 You might have noticed that the water heater  is hooked up to some sort of mystery box. 193 00:15:45,927 --> 00:15:49,855 [CLACK] What exactly is inside that box is not important for you to know 194 00:15:49,855 --> 00:15:53,160 but it allows me to disable the water heater at-will. 195 00:15:54,000 --> 00:15:56,851 Or I guess... selectively enable it. 196 00:15:56,851 --> 00:16:00,180 The water heater only has power if the red light is on. 197 00:16:01,020 --> 00:16:04,268 See, I’m in the middle of some experiments. 198 00:16:04,268 --> 00:16:08,495 Water heaters, as I said, are exceptionally well insulated. 199 00:16:08,495 --> 00:16:17,505 In fact you would have no idea there’s 40 gallons of piping hot water in there by touching the tank as it feels stone cold. 200 00:16:17,505 --> 00:16:23,580 The only heat you can really feel is what leaks out of the supply pipes -  I really oughta get some sleeves for those. 201 00:16:24,240 --> 00:16:30,300 Anyway, because this thing is so well-insulated  that means it’s effectively a battery.   202 00:16:30,900 --> 00:16:32,993 Remember that math I did earlier? 203 00:16:32,993 --> 00:16:39,176 It takes over 7 kilowatt-hours to heat up 40 gallons of water by 40 degrees C. 204 00:16:39,176 --> 00:16:41,742 And that’s… a lot! 205 00:16:41,742 --> 00:16:45,878 Electric water heaters are among the most power-hungry things in your life, 206 00:16:45,878 --> 00:16:52,092 and the cost to operate them is a big reason many people chose to use gas instead for water heating. 207 00:16:52,092 --> 00:16:57,232 I mean, just look at this! Yikes! And those are old numbers! 208 00:16:57,232 --> 00:17:01,040 Oh and by the way, the reason the cost range is so narrow is because 209 00:17:01,040 --> 00:17:04,503 energy is energy and water is water. 210 00:17:04,503 --> 00:17:11,280 Now, I have a time-of-use rate plan with my utility and  power in the middle of the night is quite cheap. 211 00:17:11,940 --> 00:17:18,900 So for the past couple of months, I have only been letting this thing operate between 1 and 5 AM.   212 00:17:19,680 --> 00:17:24,000 And believe it or not, I pretty much can’t tell. 213 00:17:24,360 --> 00:17:26,813 Now, I can feel the comments already - 214 00:17:26,813 --> 00:17:33,180 aren’t you supposed to keep your water heater hot at all times? Aren’t you the least bit worried about diseases like Legionaries?   215 00:17:34,380 --> 00:17:43,103 Well, sort of and as a precaution I did set the temperature a fair bit higher before I embarked on this journey... 216 00:17:43,103 --> 00:17:49,498 but on the other hand for years I have been shutting off the water heater whenever I leave for more than a day 217 00:17:49,498 --> 00:17:51,967 and I’m not dead yet! 218 00:17:52,310 --> 00:17:57,389 But in fairness, that could be a risk and more research is definitely needed there, 219 00:17:57,389 --> 00:18:02,580 so I am not endorsing this practice. Do not do this at home. 220 00:18:03,360 --> 00:18:07,060 I can however tell you that when that thing is “charged up” 221 00:18:07,060 --> 00:18:14,319 it will stay hot for way way wayyy longer than I thought was remotely possible. 222 00:18:14,319 --> 00:18:23,640 I've taken a shower at 9:00 at night - meaning the water heater had not operated for sixteen hours! - and the water was still scaldingly hot. 223 00:18:24,240 --> 00:18:27,300 And remember the whole “hot and cold water won’t mix” thing?   224 00:18:27,840 --> 00:18:30,677 Yeah, you’d think that after a while it would but no! 225 00:18:30,677 --> 00:18:32,239 It just doesn’t! 226 00:18:32,239 --> 00:18:36,330 I’ve taken a shower in the morning, probably using up a good half of the tank’s volume, 227 00:18:36,330 --> 00:18:42,240 and in the evening - over ten hours later - the water  from the kitchen tap was still too hot to touch. 228 00:18:42,900 --> 00:18:44,363 More quantitatively, 229 00:18:44,363 --> 00:18:52,547 I measured the temperature after running approximately 10 gallons of water through the kitchen tap at 132.4 Fahrenheit. 230 00:18:52,547 --> 00:18:57,933 Five hours later - five hours of the water heater being entirely off - 231 00:18:57,933 --> 00:19:01,439 the water measured 124.3 degrees. 232 00:19:01,439 --> 00:19:02,880 Just swapped the digits around. 233 00:19:03,840 --> 00:19:10,560 Somehow, even with at least 10 gallons of cold water  sitting in the bottom of the tank for five hours,   234 00:19:11,160 --> 00:19:14,542 we lost only 8 degrees of temperature. 235 00:19:14,542 --> 00:19:18,300 It’s wild but the cold and hot water really just don’t mix. 236 00:19:19,140 --> 00:19:25,498 Now obviously this strategy won't work for families. Good luck spreading 40 gallons a day around. 237 00:19:25,498 --> 00:19:33,769 But I think it’s worth pointing out that  this thing hardly loses any energy when it’s not getting used. 238 00:19:33,769 --> 00:19:40,051 And that makes it a really effective energy storage device - and a large one at that! 239 00:19:40,051 --> 00:19:48,524 This 40 gallon tank stores 70% of the energy that the original  Chevy Volt’s battery pack could!'I hope you can see that there’s a lot of potential for energy management  applications, here. You shut this thing off for an   240 00:19:48,524 --> 00:19:54,711 I hope you can see that there’s a lot of potential for energy management applications, here. 241 00:19:54,711 --> 00:19:59,933 If you need to shut this off for an hour or even two, you you won’t even notice. 242 00:19:59,933 --> 00:20:04,306 And, what if you put a thermostatic mixing valve on its output? 243 00:20:04,306 --> 00:20:11,677 Then, you could charge up a more sophisticated water heater well beyond your target temperature when energy is cheap and abundant, 244 00:20:11,677 --> 00:20:17,225 not only storing that energy for later, but also extending the tank's capacity. 245 00:20:17,225 --> 00:20:21,840 As a matter of fact that idea is already  in use with some heat pump water heaters today. 246 00:20:22,560 --> 00:20:28,252 I’ll be keeping track of energy costs here and  will report on how this experiment continues to go. 247 00:20:28,252 --> 00:20:33,550 I’ll probably do that on my second channel so you might want to subscribe if you haven’t already. 248 00:20:33,550 --> 00:20:42,780 But I can already say with complete confidence that a conventional, tanked water heater can be an important part of an energy-management strategy.   249 00:20:43,860 --> 00:20:47,157 People keep asking for my thoughts on tankless water heaters 250 00:20:47,157 --> 00:20:54,000 and frankly this experiment is reinforcing my previously-held belief that they’re not the be-all-end-all. 251 00:20:54,000 --> 00:20:59,554 They need tremendous amounts of power and can’t store energy for later. 252 00:20:59,554 --> 00:21:01,800 Plus they have unique maintenance considerations. 253 00:21:02,580 --> 00:21:06,360 I really think they only make sense  when you have severe space constraints,   254 00:21:06,360 --> 00:21:13,684 and personally... I gotta say that if you feel you need the “endless” hot water they can provide, 255 00:21:13,684 --> 00:21:17,789 it might be worth considering adjusting your routines. 256 00:21:17,789 --> 00:21:20,280 But that’s just, like, my opinion. 257 00:21:20,820 --> 00:21:27,483 Anyway, that whole section was basically a  teaser for my next video which will be on home electrification. 258 00:21:27,483 --> 00:21:30,885 That’s coming soon. At least I hope. 259 00:21:30,885 --> 00:21:34,741 For now, I hope what I’ve said here will get some gears turning. 260 00:21:34,741 --> 00:21:43,768 Many of the obstacles we think are insurmountable are in fact a piece of cake with just a bit of strategy and a dash of management. 261 00:21:43,768 --> 00:21:45,411 Thanks for watching. 262 00:21:46,318 --> 00:21:48,790 ♫ scaldingly smooth jazz ♫ 263 00:21:50,468 --> 00:21:54,687 You’ll find similar labels on most conventional electric water heaters. 264 00:21:54,687 --> 00:21:59,867 Oh and, by the way, that second listed wattage is  what would blet deh buh dih be deh 265 00:21:59,867 --> 00:22:03,268 And by the way, that second listed wattage is what it  would run at - 266 00:22:03,268 --> 00:22:05,568 what the heck was that noise? 267 00:22:07,740 --> 00:22:09,120 I heard a weird noise.  268 00:22:09,900 --> 00:22:13,516 Right now, the tank has a prettyform out… prettyform? 269 00:22:13,516 --> 00:22:15,291 It's pretty uniform. 270 00:22:15,291 --> 00:22:18,614 Same goes for keeping the tank warm between uses. 271 00:22:18,614 --> 00:22:23,034 And a low-flow shower head fit… oh. 272 00:22:23,034 --> 00:22:24,421 I skipped a word! 273 00:22:24,421 --> 00:22:30,597 ...combined with how we fill the tank from the bottom up turns out to be really useful. 274 00:22:30,597 --> 00:22:33,197 Remember that we have two heating elemen… 275 00:22:33,197 --> 00:22:34,648 [belches] I GOTTA BURP 276 00:22:35,947 --> 00:22:38,520 Explaining how your water heater works can be a tankless job. 277 00:22:38,520 --> 00:22:42,355 OK, that's not mine, plenty of plumbing companies the world over use that one. 278 00:22:42,355 --> 00:22:45,622 Besides, like I said I don't exactly have an affinity for tankless water heaters. 279 00:22:45,622 --> 00:22:48,203 Especially since electric ones need, like 10 kW just to provide one shower. 280 00:22:48,203 --> 00:22:50,375 Then you might as well get one of those electric shower thingies. 281 00:22:50,375 --> 00:22:51,370 Anyway, toodles.