- 2 days ago
A $30 solar water heater can turn a few feet of black pipe, a board, and sunlight into genuinely hot water. The idea is simple: black polyethylene tubing absorbs heat, water sits in the sun long enough to warm up, and if you add a barrel and a glazed box, you get a small batch solar heater that can hold more hot water for later use.
This practical homestead-style explanation walks through a low-cost solar water heater, from a bare coil for washing and outdoor use to a batch heater with thermal siphoning, insulation, and a black storage drum. It also covers the limits: warm-weather performance, freeze protection, safe mixing with cold water, and why this setup is for washing, rinsing, livestock water, or a workshop sink rather than drinking water.
The video blends old-fashioned farm wisdom with simple solar heating physics, making it useful for DIY homestead projects, off-grid living, backyard plumbing ideas, and budget-friendly renewable energy experiments. It is especially relevant if you’re looking for solar water heater plans, black pipe solar heater, batch solar heater, or a simple off-grid hot water solution.
SEO: solar water heater, DIY solar hot water, batch solar heater, off-grid hot water, homestead plumbing, renewable energy project, outdoor wash water, workshop sink heater, livestock water heater, and low-cost solar heating ideas for homesteads, cabins, and farm use.
This practical homestead-style explanation walks through a low-cost solar water heater, from a bare coil for washing and outdoor use to a batch heater with thermal siphoning, insulation, and a black storage drum. It also covers the limits: warm-weather performance, freeze protection, safe mixing with cold water, and why this setup is for washing, rinsing, livestock water, or a workshop sink rather than drinking water.
The video blends old-fashioned farm wisdom with simple solar heating physics, making it useful for DIY homestead projects, off-grid living, backyard plumbing ideas, and budget-friendly renewable energy experiments. It is especially relevant if you’re looking for solar water heater plans, black pipe solar heater, batch solar heater, or a simple off-grid hot water solution.
SEO: solar water heater, DIY solar hot water, batch solar heater, off-grid hot water, homestead plumbing, renewable energy project, outdoor wash water, workshop sink heater, livestock water heater, and low-cost solar heating ideas for homesteads, cabins, and farm use.
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LifestyleTranscript
00:00You have already built this once, by accident, and it burned your hand.
00:05A garden hose lying across the yard on a July afternoon.
00:09You go out to water something, you squeeze the trigger without thinking,
00:14and what comes out of it is hot.
00:16Properly hot.
00:18Hot enough that you let go of it and say something you would not say in front of your mother.
00:23Then you stand there while it runs cold, and you water the beans,
00:27and you never think about it again.
00:30That hot water was free.
00:33It cost nothing.
00:34Nobody burned anything to make it, and you poured it on the ground.
00:40I am Elias Yoder, and what I want to show you is that the hose was the whole machine.
00:46Black pipe, a little water inside it, and the sun.
00:50There is nothing else to it.
00:52All anybody has ever done since is make that accident happen on purpose
00:58and keep what comes out.
01:00My grandfather is the one who pointed it at me, and he enjoyed it a good deal more than I
01:06did.
01:06I would have been nine or ten, and I had done exactly what I just described,
01:11out by the pump house, and I dropped the hose and hopped about, and he did not come running.
01:17He stood there and laughed at me until he was finished laughing.
01:22Then he picked the hose up himself, held his hand under it for a second,
01:27and said that right there was the cheapest hot water on the place,
01:31and I had just thrown four buckets of it into the dirt because nobody had ever told me to put
01:37a bucket under it.
01:39The sun is already heating it.
01:41The only question is whether you kept any.
01:45I gathered the whole of it into a book at EliasYoder.com.
01:50The book is the long version.
01:52If you want it, it is there.
01:54I will not mention it again.
01:57Now, before I show you the build, I am going to tell you what this is not,
02:02because I would rather you were pleased with it than disappointed.
02:06This is a warm weather thing.
02:08On a clear day, it is remarkable.
02:11On a cold gray one, it does very little,
02:14and in a hard freeze, you must empty it,
02:17or the water inside turns to ice and splits the pipe open.
02:22So this is for an outdoor wash,
02:24a shower outside in summer,
02:27the sink in the shop,
02:29a camp,
02:29a cabin,
02:31warming water for the stock,
02:33taking the chill off a pool.
02:35It is not a replacement for whatever heats the water in your kitchen in February,
02:41and I am not going to pretend otherwise.
02:44Understand that, and it will delight you.
02:47Ask it to run a household in January,
02:50and it will let you down.
02:52Here is the simple build,
02:54and it is almost nothing.
02:56A roll of black poly pipe,
02:59the flexible sort sold for irrigation at any hardware store,
03:03half inch or three quarter,
03:05a hundred feet of it for somewhere around twenty to twenty-five dollars.
03:09A sheet of plywood or an old board.
03:13That is the list.
03:15Lay the board flat and coil the pipe onto it in a tight spiral the way you wind a hose,
03:22and fasten it down with staples or zip ties so it stays where you put it.
03:27Fit a hose connector on one end for your inlet.
03:32Lean the board against a wall that gets the sun,
03:35or lay it flat, facing up.
03:38Run the hose in until the pipe is full,
03:41and then, here is the part the videos get wrong, and it matters.
03:45Do not close both ends.
03:48If you cap one end and shut the other and walk away,
03:53you have made a sealed pipe full of water sitting in the sun.
03:58Water swells as it heats,
04:00and in a closed pipe that swelling has nowhere to go,
04:04and what gives way is a fitting,
04:07usually while you are standing next to it.
04:10So, leave the outlet end open,
04:13or put a tap on it and leave the tap cracked,
04:16or run the far end up into an open bucket or a vented barrel.
04:22Something has to be able to breathe.
04:24It is a two-minute decision,
04:26and it is the difference between a water heater and a surprise.
04:31Where you stand, it matters nearly as much as what it is made of.
04:36It wants the side of the building that gets sun through the middle of the day,
04:41which in this country means facing south,
04:44and it wants nothing shading it between about ten in the morning
04:48and three in the afternoon.
04:50A tree that is bare in April
04:52will be throwing shade across the whole thing by June,
04:56so look up before you fix anything down,
05:00and lean it rather than laying it flat on the ground,
05:03both because a leaning board faces the sun more squarely,
05:07and because a coil lying in the grass
05:09is a coil losing heat into the ground all afternoon.
05:13A few inches of air behind it is worth having.
05:16Now, why a coil of cheap pipe does this at all?
05:20Because it is two things working together,
05:22and neither one alone would do it.
05:25The first is color.
05:27Black takes in nearly all the light that lands on it,
05:30and turns it straight into heat,
05:32where anything pale or shiny throws most of it back.
05:36That is why a dark seat in a parked buggy or a car
05:40will cook you in August,
05:42and a light one will not.
05:44The pipe is a sponge for sunlight,
05:47and the water lying inside it
05:49drinks up what the pipe takes in.
05:51The second is shape,
05:53and this is the part people miss.
05:55A hundred feet of pipe laid out on a board
05:58puts an enormous amount of black surface in the sun
06:02while holding only a very little water inside it.
06:06A great deal of collector.
06:08Hardly any water.
06:10And that water is not going anywhere,
06:12so it sits there all afternoon,
06:15taking on heat with nothing to carry it off.
06:18Thin water,
06:19wide black surface,
06:21patient sun.
06:22That is the whole of the physics.
06:24Which tells you how to run it through a day.
06:27Fill it in the morning,
06:29and then leave it alone.
06:30It climbs slowly all through the middle of the day,
06:34and it is at its hottest
06:35sometime in the middle of the afternoon,
06:38and it stays hot a while after that
06:40because the sun has stopped putting in,
06:43but nothing has yet taken out.
06:45So do not go and open the tap at noon
06:48to see how it is getting on.
06:51Every gallon you draw off
06:53is replaced with cold from the hose,
06:55and you have started the whole afternoon over again.
06:58Leave it be until you want it.
07:01This is the same lesson
07:03as nearly everything else I have ever told you,
07:05which is that time is doing the work,
07:08and your job is mostly to stay out of the way.
07:11Now, two things about that little bit of water,
07:14and the first one is a warning
07:16I want you to hear before you build anything.
07:19That water gets hotter than you think,
07:21and hot water hurts faster than people believe.
07:25Water at 140 degrees
07:27will take the skin off an adult in a few seconds.
07:30Not a few minutes.
07:32Seconds.
07:33On a child or on somebody old,
07:35it is quicker still,
07:37and a glazed one of these on a hot, clear day
07:39will go past 140 without any trouble at all.
07:44I have seen this thing presented as a selling point,
07:46that the first water out will make you jump.
07:49That is backwards.
07:51That is the hazard,
07:52and it is the only genuinely dangerous part
07:56of this whole build.
07:57So you plummet so there is cold to mix with.
08:00Always.
08:01Run your cold line to the same tap
08:04or the same shower head
08:05so you can bring it down to what you want,
08:07or fit a mixing valve,
08:09which is a cheap bit of brass
08:11that does it for you
08:12and will not forget.
08:14Never put a child
08:15or anybody who cannot get out of the way
08:18under an outlet
08:19that has nothing but collector water
08:21coming out of it.
08:22And always turn it on,
08:24point it away from yourself,
08:26and let the first of it run.
08:28The second thing about that little bit of water
08:30is how little it is,
08:32and this is the number nobody gives you.
08:35A hundred feet of half-inch pipe
08:37holds about one gallon.
08:39Three-quarter inch
08:40holds somewhere near two and a half.
08:42One gallon is a wonderful thing.
08:45It is washing your hands
08:46in genuinely hot water.
08:48It is a bucket for scrubbing.
08:50It is rinsing the mud off.
08:52It is a basin to shave at.
08:54It is not a shower.
08:56A shower uses a couple of gallons a minute,
08:58so a bare coil gives you
09:00about half a minute of hot,
09:02and then you are standing
09:03in cold water with soap on you.
09:06Which brings us to the upgrade,
09:08and the upgrade is not a nicety.
09:10It is the thing that turns this
09:12from a trick into something you would use.
09:14You want storage,
09:16and you want a cover over it.
09:18Take a barrel, metal or dark plastic,
09:20and paint it flat black.
09:23Build a simple box rounded out of boards
09:25and put an old window
09:27or a sheet of clear plastic across the front.
09:30That is it.
09:31Two things change at once.
09:33The barrel holds many gallons instead of one,
09:36so there is enough for a real wash,
09:38and that much water cools slowly,
09:41so it is still warm in the evening
09:43when you actually want it,
09:45rather than at two in the afternoon
09:46when you do not.
09:48And the glass does the thing
09:50a greenhouse does.
09:51Light comes through it,
09:53lands on the black barrel,
09:54turns to heat,
09:56and then cannot get back out
09:57as easily as it came in,
09:59and the wind cannot strip it off
10:01the way it strips a bare coil.
10:04Trapped heat against a big black tank
10:06is a different machine
10:08from a pipe on a board.
10:10On the barrel itself,
10:12a food-grade plastic drum
10:14is the usual thing,
10:15and they turn up cheap or free
10:17from anybody who buys in bulk
10:20a bakery, a car wash,
10:22a farm supply.
10:23Fifty-five gallons is the common size,
10:26and it is more than most people need.
10:29Twenty or thirty gallons
10:30will give a couple of good washes
10:32and will come up to heat
10:33a great deal faster
10:35because a big barrel
10:36on a short day of weak sun
10:38simply ends up tepid,
10:40which, as you will hear shortly,
10:42is the one state you do not want it in.
10:45Paint it flat black,
10:47not glossy.
10:49Flat takes in more
10:50and throws back less,
10:52and it is the cheapest improvement
10:54on this entire build.
10:55This is called a batch heater,
10:58and it is not a new idea.
11:00It ran ordinary households
11:01for a good many years
11:03before anybody thought it was clever.
11:05Now the part that feels like cheating,
11:08and it is free.
11:09Hot water rises,
11:11cold water sinks.
11:13That is always true,
11:15and you can build a pump out of it.
11:17Set your storage barrel
11:18higher than your collector.
11:20The sun heats the water
11:22in the collector.
11:23That warmed water rises on its own
11:26up into the barrel,
11:27and the cooler water
11:28at the bottom of the barrel
11:29slides down to take its place
11:32and get heated in turn.
11:34The whole thing circulates itself
11:36all day,
11:37with no pump,
11:38no power,
11:39and nothing that can break.
11:41It is called a thermosiphon.
11:44You get the heights right once,
11:46and then heat and gravity
11:48run it for as long
11:49as it stands there.
11:50Two smaller things worth doing.
11:53Insulate every bit of pipe
11:55that carries hot water
11:56away from the collector.
11:58Foam sleeves cost very little,
12:01and it is a sorry thing
12:02to heat water for nothing,
12:04and then lose half of it
12:05in 20 feet of bare pipe
12:07on the way to where you are standing.
12:09And if you build the glazed box,
12:12lean the glass back toward
12:14where the sun sits at midday
12:16rather than standing it bolt upright.
12:19The difference across a whole day
12:21is not small.
12:23Now the water itself,
12:24and there are two things to say,
12:26and I will say them plainly.
12:28The first is that warm,
12:30standing water grows things.
12:33Not boiling water,
12:35and not cold water.
12:36water, lukewarm water,
12:38somewhere between a tepid bath
12:40and a warm one,
12:41which is exactly what
12:43a half-heated tank sits at
12:44for days on end.
12:46And the way it reaches you
12:48is not drinking it.
12:49It is breathing the mist.
12:51Which means a shower
12:53is the riskiest thing
12:55on the whole list,
12:56because a shower is a machine
12:58for turning water into mist
13:00and putting it
13:01where you are breathing.
13:02So you do one of two things.
13:05Either you use it regularly
13:07and let it get properly hot
13:09on good days,
13:10which deals with it,
13:11or you drain it
13:13and let it stand dry
13:14between uses.
13:15What you do not do
13:17is let it sit half warm
13:19for a fortnight
13:20and then stand in the spray of it.
13:22The second thing is the pipe.
13:25Black irrigation tubing
13:27is made for watering a field.
13:28It is not made for drinking water
13:31and it is not made for hot water
13:33and I would not put my mouth under it
13:36or fill a kettle from it.
13:37So this is wash water.
13:40Washing, rinsing, scrubbing,
13:42the stock trough, the pool.
13:45If you want hot water,
13:46you can drink.
13:47That is a different pipe
13:49with a different rating on it
13:50and a different price
13:51and you should go and buy that one
13:54rather than take my word
13:55for the cheap stuff.
13:57There is one use for this
13:58that has nothing to do with washing
14:00and it is the one
14:02I would put first on a farm.
14:04A black trough
14:05or a black barrel
14:06standing where the sun gets at it
14:08keeps stock water
14:09from being bitterly cold
14:11and animals drink more
14:12when the water is not ice
14:14on their teeth
14:15and an animal that drinks properly
14:17does better in every other way.
14:19You do not need a shower head
14:21or a barrel in a box for that.
14:23You need a dark tank in the sun
14:25instead of a galvanized one
14:27in the shade
14:27and that is the whole job
14:29and it costs you a tin of paint.
14:32And before the first frost,
14:34empty it.
14:35All of it.
14:36The coil and the barrel
14:37and every low spot in the run.
14:40Water that freezes in a pipe
14:41will split it from the inside
14:43and you will find out in the spring.
14:46Draining properly
14:47takes thinking about once
14:49when you build it
14:50rather than scrambling
14:51on the night of the first frost.
14:53Put your lowest fitting
14:55at the actual lowest point
14:57of the whole run
14:58and make it something
14:59you can open with your hand.
15:01Then tilt the board
15:03so everything runs toward it
15:04and if you can put a bit of air
15:06through the coil
15:07from the other end afterward,
15:09do,
15:09because a coil holds water
15:11in its bends
15:12long after you think it is empty.
15:14One last thing worth knowing,
15:17because people act as though
15:18this were invented
15:19on the internet last year.
15:21A man named Clarence Kemp
15:23patented a commercial
15:24solar water heater
15:26in 1891
15:27and called it the Climax
15:29and it was black tanks
15:31in a glass-topped box,
15:33which is the barrel
15:34you just read about.
15:35In 1909,
15:37another man,
15:38William Bailey,
15:39separated the collector
15:40from an insulated tank
15:42so there was still hot water
15:44after dark
15:44and his design sold
15:46in the thousands
15:47in California and Florida
15:48until cheap gas arrived
15:51and pushed it off the market.
15:53Everything on a roof today,
15:55the expensive ones included,
15:57is running the same idea
15:58those two men had
16:00before most people
16:01had a motor car.
16:02You are building the version
16:04that costs $30.
16:06Now the plane limits together
16:08so you can decide.
16:10It is seasonal
16:11and it is weather dependent
16:13and nothing fixes that.
16:15The bare coil
16:17holds about a gallon
16:18so it is a wash
16:19and not a shower
16:20and if you want a shower
16:22you are building the barrel.
16:24It will not heat
16:25your house water
16:26and it is not plumbed
16:27to any code
16:28so do not tie it
16:30into the household system
16:31unless somebody
16:32who knows the rules
16:33where you live
16:34says you may.
16:36And it is wash water
16:37not drinking water
16:39and not for a child
16:40without cold mixed in.
16:42There is no scheme
16:44in any of it either
16:45though it is worth
16:46seeing the shape.
16:47Heating water
16:48is one of the largest things
16:49on an ordinary power bill
16:51second only to heating
16:53and cooling the house itself
16:54and there is no money
16:56at all in telling a man
16:57that a roll of black pipe
16:58and an afternoon of sun
17:00will do a share of it.
17:02There is a great deal
17:03of money in the tank
17:04in his basement
17:05that runs all night
17:06keeping 40 gallons hot
17:08for the two showers
17:09he actually takes.
17:11My grandfather never
17:13built one of these.
17:14What he had was the sense
17:15to notice that the sun
17:17had already done the work
17:18and the only failure
17:20was that nobody
17:21had put a bucket under it.
17:23Tell me in the comments
17:24what you would put
17:25the first one on
17:26because I expect
17:27it is an outdoor tap
17:28or a shop sink
17:29for most of you
17:30and I am curious
17:31whether anybody
17:32has a use
17:33I have not thought of.
17:34And if you are new here
17:36tell me roughly
17:37how many clear sunny days
17:39you get in a year as well
17:40because that one number
17:42decides whether this is
17:43a toy where you live
17:44or a tool.
17:46Next time I want to go
17:47the other way with water
17:48into the cold
17:49because keeping a trough
17:51and a line from freezing
17:52without a heater in them
17:53is the other half of this
17:55and it is the half
17:56that comes round
17:57in about six weeks.
17:59The sun is already heating it.
18:01The only question
18:02is whether you kept any.
18:03The people who built
18:05this country
18:05with their hands
18:06knew that
18:07and we are only
18:08just starting to remember it.