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What We Covered
Conventional electric water heaters depend on the power grid and use tons of electricity, making them unsuitable for an off-grid solar power system.
Thankfully, we have a number of great off-grid alternatives to choose from. Some are very convenient, while others are totally renewable and independent. Whatever your goals, this episode will equip you with an overview of the options you need to know about.
00:00 – Intro
01:28 – Why conventional electric water heaters are problematic
03:23 – Propane: conventional tank water heater
04:43 – Propane: tankless (on-demand) water heater
08:46 – Solar water heaters
11:13 – Wood cook stove / water coil / range boiler / thermosiphon water heater
15:31 – DC electric element for burning off excess solar power
17:47 – Outdoor wood furnace
19:37 – Wrap up
- More info on range boiler thermosiphon system
- DC electric heating elements
- Sustainable Preparedness – details on how to make your homestead systems (water, power, heat, etc) more independent
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Welcome back to The Ready Life podcast where you are empowered to make your homestead as independent as possible for basic necessities like water, heat, food, and power. In this week’s episode, we’re going to be talking about off-grid hot water. I know when I first learned about living off the grid years and years ago.
That was 1 of my first questions. Is there a flushing toilet? Is there water? Can I take a shower? What about hot water?
Well, there are a lot of different ways that you can make hot water even living off the grid. And today we’re going to look at a number of those different options. Now I know a little bit about off-grid hot water because we use it. But all of the technical stuff, that’s where the brains are. So he’s going to be doing most of the talking today.
I can tell you about what the options are and then he’ll tell you more about the details. So. But before we talk about what the options are, maybe we should talk about what we should not use for heating water off the grid. That’s very true. And that would be an electric water heater.
In fact that is part of the big 4 that we refer to quite a number of times. There are 4 big power consumers in your home and if you can switch those to an alternate energy source then you’re going to reduce almost 80% of your home’s power if you’re using all 4 of these items as electric options. And the big 4 are your oven range, your clothes dryer, see if I can remember this off the top of my head, your HVAC system and your hot water. So today we’re going to talk about hot water and alternate options. That’s right.
And the electric water heater, it would just use massive amounts of power and it would just be cost prohibitive. Yeah unless you have an unlimited budget in which case you can skip this episode. Yes, the sky’s the limit you can do pretty much whatever you want these days. Wasn’t always the case but now you can build systems so big that you could do pretty much anything you wanted if you wanted to throw tons and tons of money at it. But that’s not what we’re about.
That’s right. We did this on a shoestring budget and we’re here to show you how you can do it just the same way. But yet have a quality system. I don’t like doing things cheap. We’ve gotten burned so many times when when you buy cheap and so you want to go quality but yet be cost-effective.
And efficiency is 1 of the biggest ways that you can do that to have a quality off-grid solar system that is reasonably priced. So what can we use for heating our water off the grid? Well obviously the most the easiest and option that is exactly like from a user standpoint exactly like what you’re doing right now with your electric water heater is to use a propane water heater. And there are a couple main styles of propane water heaters. There’s your conventional tank style water heater where you’ve got a 40 gallon or whatever size tank and there’s a flame in there, a little propane burner that heats the water up.
That is totally feasible off the grid. In fact most of those don’t use any power if you can get a simple 1 you know there’s there’s no electricity required it’s just propane heating the water up. So totally feasible however I will say those aren’t necessarily the most efficient options from a propane standpoint because you are keeping a 40 gallon tank of water hot 24-7 whether you need it or not. If you’re constantly using hot water then you know maybe a tank water heater is is efficient enough for you and it might actually do okay but if you have periods of time where you’re not using hot water, for instance when you’re sleeping or if you have periods of time where there’s nobody in the house, nobody using hot water, then a tankless or on-demand water heater becomes more and more efficient and you can use quite a bit less gas with those types of units. And did anyone say long, hot showers?
That’s the other thing. I love tankless water heaters for that reason alone, even without the efficiency. You never, never run out of hot water. We have unlimited hot water. Yeah.
And if you haven’t guessed already, we have a tankless propane hot water heater and we love it. Yes. It is however more complicated. There’s more to go wrong with a tankless water heater. There’s more intricate parts, as I have found out.
Ours is an oldie, oldie goldie. I think it’s circa 2005, somewhere thereabouts. It’s hard to believe that that would be considered oldie goldie I’m feeling old all of a sudden well but we’re talking water heaters you know water heaters aren’t supposed to last all that long you know what is I don’t remember the average lifespan but I’m thinking somewhere in the neighborhood of 15 years maybe 20 something like that you figure for a water heater so yeah it’s It’s an old 1 and I’ve had to tinker with it. It’s nearing the end of its lifespan and I’ve had to tinker with it some to get it to work, you know, clean out a jet or things like that. There are more parts to go wrong with it, but man when it’s working it’s so nice and as long as yours isn’t an ancient water heater then it should work fine.
So the 2 main styles now I believe there only used to be 1 the what we now call the non-condensing units. But nowadays, there’s non-condensing and condensing. And I’m not going to try and go into all of the intricacies of that, but just some general pros and cons of each. With the condensing, it’s condensing type of tankless propane water heaters. They’re more efficient, so they don’t use as much gas.
They transfer more of the heat to the water. They can be vented with even a PVC pipe because it extracts so much of the heat into the water that the exhaust coming out is not very hot and it can be vented with PVC. And it does require a drain though because there is some condensate that needs to be drained. I believe it’s highly alkaline so you got to have a special drain for that so it could be a little bit more limiting and where you place it because you have to have it in a location where it can have a drain and things like that. And I believe, if I recall right, I believe that all other things being equal, a condensing is going to be more expensive for the unit itself.
With the non-condensing it may be a little smaller, more flexible on placement because there’s no drain required, but the vent is going to be more expensive because it has to be able to handle higher temperatures. So it’s going to be a more expensive larger vent that goes up through the roof to vent it. So that’s the kind we have, right? That’s the kind that we have, the older kind, the non-condensing, which are still made. They’re still made.
So there’s pros and cons to each, and I’m not gonna belabor which is better than the other. You’ll have to decide that for yourself. But that’s just a little bit about those, and that takes us to solar water heaters. Solar water heaters, yes. Which is an interesting option, especially for those of you who are in consistently sunny climates.
Some of them can be quite efficient. I talked with a fellow once that told me he had a solar water heater, the evacuated tube type, and he said that he was in, I think he was in Indiana, and he said that it was, like, sleeting outside, so it was in the low 30s, and he was getting nice, pretty warm, pretty hot water off of the thing. Now, I don’t know if that’s typical or not, but the evacuated tube models are more efficient and they are able to extract more heat transferred into the water with fewer losses and things like that and but they are more fragile there’s you know the evacuated tube there’s glass It’s just the whole unit is more fragile. The more durable or tougher models are the flat panel models, and they look more like a solar panel. And so those are probably gonna be a better option if you’re in snow country, where snow can pile up on your roof, or if you’re in an area that gets hail, where you don’t want something that’s a little bit on the fragile side.
And so, but it’s, you know, 6 of 1, half dozen of another. I mean, not exactly. There’s pros and cons to each is what I’m trying to say. And so you’ll just have to pick which is the better option for you. But I would not figure that you’re going to be able to produce all of your hot water with that solar water heater, there’s going to be days where you can’t, where you’re just not getting enough, especially in northern climates.
If you’re in Arizona, then maybe so. But in northern climates, then it’s probably, you’re gonna have downtimes with the solar water heater. And so it’s a good idea to plumb in a backup, like a on-demand propane water heater, something like that. You can plumb that into the system where it runs when the solar water heater isn’t making the water hot enough and things like that. So that’s an option as well.
What’s another option, 1 that we actually used in the past? So my favorite option is a wood cook stove. You know I was just thinking with the wood cook stoves they actually solve 3 of those 4 those big 4 power consumers in your home. The HVAC which heats your home, the wood stove would heat your home and then your oven range because you can cook and bake on a wood cook stove and you can plumb in a hot water system with your wood cook stove. We actually had that where we lived yeah previously and we loved it We had so much hot water.
And it was hot. And the wintertime. Yeah, in the wintertime. But then in the summer… Yeah, the Summertime, it was more challenging.
He did something really cool. Summertime, of course, you don’t want to be running your wood cookstove. You’ll cook yourself out of the house. And so we actually came up with an option where, so let me just explain the first, we should probably explain the wood cookstove heats the range boiler thermosiphon system works so basically you’ve got your wood cookstove inside the firebox is a water coil and that’s basically a heavy-duty stainless steel pipe that runs in does a ue 180 degrees turns back and comes back out of the firebox. While it’s in there the the water gets heated up because this this pipe is inside the firebox where it’s piping hot so it’s plumbed into your system the water gets hot and then the water coil is plumbed into a say 40 gallon tank called a range boiler and it looks a lot like a conventional water heater except it’s a heavier duty tank.
I have heard of people using regular water heater tanks for this but we decided to go with a heavier duty model that’s thicker metal and everything And so basically you plumb your water coil, you hook it up to this range boiler, and the range boiler has a port down low and a port up high. And what that enables you to do is to use the principle of a thermosiphon to your advantage, because heat does what? Well, heat rises and cold sinks. Right, so when the water in that water coil that’s in the firebox, when it heats up, it’s naturally going to want to go up. So it takes the path of least resistance and goes to the top of the tank.
It wants to go up and we have a pipe that’s running up to that top port in the in the range boiler and then what happens is the heat of course is up in the upper portion of that range boiler the colder water is down in the lower portion of that range boiler and so the lower port on the range boiler runs into the other side of the water coil in the firebox and so basically it makes a loop essentially where the hot water the hot water goes up to the range boiler and as it flows up it’s pulling cold water in behind it and it starts this circle happening where before long you’ve got a tank full of hot water with no electricity required no pumps nothing that is so cool and I love and I loved it it was so incredible great it was really nice but the question is what do you do in the summertime? So well, 1 question before the summertime, though, I was just thinking about that range boiler. Isn’t there some kind of a relief valve? If the tank gets too hot, then there’s a way that it can let off steam.
Right. We’ve got a whole blog post about this. We’ll link to it in the show notes. If you go to the show notes, the link to the show notes will be in the description for this episode. But yes, there’s a pressure relief valve so that if the pressure gets too high it will blow off the extra pressure there for sure.
Any water heating system needs to have that. But what do we… Summertime. So then summertime what do we do for hot water? Well, we take advantage of that range boiler that we already have sitting there.
And we are not using the wood cook stove, so we’re going to shut that off, close the valves for that. And then this range boiler, it had all kind of ports on it, and it had some extra ports that we weren’t using. And so I was able to get a DC electric heating element. So in your conventional electric water heaters, they have heating elements that screw into them. They’re high power, like AC, 240 volts, and they are heating up the water in your water heater, And they are, you know, using electric resistance heat to heat the water up.
So I found a electric heating element that will run off of our DC power from our batteries, the direct current power from our, straight off of the batteries, and would heat up and heat our water in the summertime with the excess solar power that we weren’t using otherwise. And I was able to set that up where it had its own little special charge controller that when the voltage of the batteries would get up to a certain point it would burn off the excess power into that heating element and heat up our hot water in the summertime. I will say if you don’t have a really oversized system then you’re not going to have a ton of hot water with that. But we, if by the end of the day, in the evenings, we could take a quick hot shower and it was nice and comfortable, especially if you insulated the range boiler and the pipes, then it was workable. If you oversized your solar system, then yeah, you could have a good bit of hot water, maybe even use 2 heating elements.
But that was a really cool option for supplementing with the wood cook stove range boiler system and it worked reasonably well. No electricity required, no grid power required, no pumps or anything. Very cool. Yeah so I guess another option would be to take your fire outside during the summer to heat your hot water and I think that there isn’t there a hot water system That works with an outdoor furnace. Mm-hmm.
Yep. What outdoor wood furnaces? Will typically be Used to heat water and then or liquid of some form and then the liquid is run into a radiant floor heating system in the house but you can also tap into that with a heat exchanger to create hot water for your domestic hot water system. And so yes that’s an option as well those can use a good bit of wood so don’t expect to be you know you’re gonna need to do a good bit of wood cutting in the winter. But they do use larger chunks of wood, and so you don’t…
You have to cut and split it, yeah, it’s so small. It’s not like you have to have twice as many cords of small firewood. You’re doing bigger pieces. So it does take more wood for sure, but not necessarily a huge amount more work. But that is another way that you could heat your hot water.
Once again it may not be something that you want to do in the summertime just because who wants to burn a fire in the summertime and you definitely don’t want your radiant heat floor, your radiant floor heating system going in the summertime but it is another possible way to heat your hot water. Maybe a flash fire at least it’s outside. Yeah maybe or just once again plumb in a propane water heater as a backup. Yeah yeah and we really like our tankless propane water heater so so there’s a lot of options for heating your hot water even if you have a small energy efficient off-grid solar power system It’s just all about strategy and choosing the right appliances and things like that but you can do pretty much what you want to just gotta use strategy to your advantage. Anyhow I hope that’s been helpful in learning about heating your hot water off the grid.
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