Water requires a great deal of energy. In California for example: extracting, treating, moving, heating, and disposing of it account for about 30% of the state’s total energy usage. That’s a lot! What can we do to reduce water and energy waste for ourselves?
Houses need replumbing sometimes and this gives a great opportunity to save water and energy… and get better performance from the system. By the way, installing an efficient plumbing system can cost less that putting in an inefficient system! Manifold and demand systems are two approaches to look at. Simply installing low-flow fixtures can backfire if hooked up to an inefficient system. It will slow flow rates in the lines and cause longer waits for hot water at the shower and elsewhere.
Manifold plumbing, to put it simply, means running an individual small line to each fixture. If the fixtures are close together, as is common in older homes, this could be a great way to save water and energy and get hot water much faster. Also, it could mean running small (like 3/8”) tubing to the fixtures, which is much easier than running bigger pipe. Demand controlled systems use the typical main and branch plumbing, but add a pump to push the cooled water out of the hot line into the cold or a dedicated return, so when you turn on a tap, you get hot water quickly, with far less waste. They are great for retrofits where the plumbing system is basically sound, but inefficient.
The simple act of heating water seems to divide us into different camps. Tank-type heaters versus tankless. This is a question where all the circumstances around what heater is used, need to be considered. Will the owner maintain the equipment? How hard is the water? Tankless doesn’t like hard water. What sort of hot water service is needed? A one-size-fits-all approach really doesn’t fit here!
And then there is the 120-degree water vs 140-degree question… or named differently, Legionnaires disease vs scalding. The plumbing community still doesn’t fully agree on how to make this decision. There are a variety of mixing or tempering valves which can help, but hard water or incorrect sizing will play havoc with them. If there are any very old, young, or immune compromised people in the house, it makes sense to store the water hotter and then mix it down to a safe temperature. Otherwise, I like to keep water around 130 degrees and just be careful when using it. Having the heater hooked up to efficient plumbing will go a long way towards making the water better/safer for use also. If the piping is sized right, water will travel down the line at a rate of at least one foot per second. This will scrub the lines, helping prevent slime and bacteria from growing in the pipes. Staying healthy is a nice side benefit of efficient plumbing!
Still, whatever the equipment or its usage, opportunities likely exist, depending on building shape and orientation for energy savings via heat recovery and/or solar heating. Shower drain heat recovery is one great way to plug an energy leak. It can capture 60% of the energy that would have gone down the drain. Efficient fixtures on small lines are another approach. Running hot water only to places that actually need it is another. Many dishwashers can heat their own water, so a hot supply isn’t needed. Clothes may not need to be cleaned in hot water as modern detergents can do the job. Certainly, other opportunities will show up if we look for them.
Maintenance can greatly extend equipment life. I’ve gotten fifty years from tank-type water heaters with simple maintenance, yet we’re told to worry if the heater is over ten. A life-cycle cost approach can be used to bring order when thinking about water heating choices. When all costs over time are taken into account, it becomes easy to see what equipment really costs less and which approach saves the most energy and water. Then you can factor in the savings in waiting times, headaches when equipment fails on holidays, and reduced risk of flooding and property damage.
On another topic, outdoor water usage may be controlled with thoughtful yard design, grey water, and rainwater catchment. Houses often use far more water outdoors than inside. People think pools use a lot of water, but then don’t think about their lawns!
Looking at our overall water usage, compared to other countries, there is just a little room for improvement. Around the world, the most water efficient people are in Africa, using as little as 392 cubic feet of water per person per year. In America, we use from 36,600 to 189,740 cubic feet per year! That’s up to 484 times as much. We’re amongst the least water efficient in the world. I imagine we can do a bit better. The Western US is looking at another drought, so we have no choice but to do better, and quickly. I’ve found that with energy efficiency, it’s not all that hard to get by comfortably on 20% of the power most people use. I imagine we can do something similar with water if we step away from old habits and get creative.
I know I’ve wandered all over the world with these ideas, but hopefully have given you some ideas and things to look into to get the benefits of saving water and energy for yourself.
You’ve certainly heard that a picture is worth 1000 words. Actually, there are times when words simply cannot convey the message, so no quantity of words will work.
I’m a visual thinker as most technical people are. We “think” in pictures, moving ones if we’re lucky. Of course, physically being there is best when trying to understand the past, present and future of something, but a picture is a nice second best. For example, the picture you see here shows my cat, Rex with his arm over young Prince, who’s enjoying a little warmth and adult supervision. What the photo can’t tell you is that I rescued Rex from a trash pile when he was about four weeks old…bottle fed him every three hours to keep him going…had him bond with me in ways I’d never experienced before with a feline and too few years later, had to deal with the vet not knowing how to help him when he got sick. He died at the vets’, while I held him.
Prince is another cat from the wild, and Rex was his security growing up. When Rex left, (and we had to evacuate due to a fire) Prince reverted to being a skittish and scaredy-cat. I’m only slowly bringing him out of that way of being, to something more comfortable. The photo reminds me of the whole timeline for both cats and my place in it. I could write far more than 1000 words and not come close to conveying everything I see and feel in that photo. There is so much history behind that photograph!
It works the same for mechanical equipment and built things. A photo may show a pretty house and give you clues about the place, but go snooping around that old house. Climb around in the attic and have a look in the basement. The house has so many stories to tell about how it was built and about how it grew up and spent its time. It will show its’ experience in different ways. You may see the evolution of building techniques, tools, and materials. You’ll definitely see the skill or lack of it, that the hands working on the house over time, possessed. You may be able to read in how well off, or poor the owners of the house were at times. There may be other clues, like trash left behind that now is a little time capsule of events (What is that old fashioned screw cap beer can doing in the attic?). I’ve found old printers’ plates from the local newspaper used instead of tarpaper under shingles! They gave a very good idea what was happening when the roofing work was done on that old house, along with telling a tale of creative scrimp and save.
Plumbing has its own ways of telling you what it’s been through. From solder drips and green corrosion on copper pipe, (meaning the plumber could have been in a hurry or was not very careful in cleaning up their work… particularly in not completely washing off the flux) to various valves not working correctly, (often meaning that hard water scale has built up inside, on the working parts) plumbing loves to tell its’ stories to those who pay attention. Various types of corrosion also give great clues about what the piping has seen. Simply where on a pipe the corrosion or damage is, tells a story of too much flow (erosion corrosion, particularly after 90-degree bends), acidic water in copper pipe, (pin-holes anywhere in the line), or leaks along the bottom of horizontal iron drain lines (slow and steady flow for years, creating a waterline and eating through the iron at the air/water interface).
I like to look at plumbing (or other things) and imagine what it’s experienced and been through, then think of these forces over time. That way I can “see” better what has happened and what will probably happen in future.
I frequent a site on the internet called HeatingHelp. On it are many experienced plumbing and heating folks who help solve anyone’s problems, at least as they relate to the trades 😉 Whenever someone shows up with questions about their boiler or whatever, one of the first things the pros ask for is photos. The photos tell a story and give clues. So often, the person asking questions is made aware of important stuff they had not considered, just because of what the pros see in those photos. Sometimes the photos reveal a possible life-threatening situation the questioner wasn’t at all aware of!
Just like words, photos have their limits. As 1000 words can’t always do what a photo can, 1000 pictures can’t always tell you what a visit to the real thing will show. There is no real substitute for putting your hands on something, seeing, hearing, and smelling the environment it lives in, to encourage it to tell you more stories. Still, even a visit to see and experience the real thing can’t always shine a bright enough light on the mystery of what has happened there in years past. I guess we’ll just have to develop a good way to travel in time!
Following is a brief exploration and perhaps teaser of what’s possible in having, and efficiently using water. The purpose is to reexamine our assumptions about water and energy use, so that we can get far greater savings than are considered normal. I also hope to show that efficiency can help you to greater comfort, independence, and maybe even a touch of financial freedom.
One big difference between first and third world countries is plumbing. Working sewage systems save more lives by far than medicine does, but that’s another story. Here in the US, we have toilets and hot showers, but third world people can show us something about how to get by on far less water. If you had to carry clean water to your home to be used, I’ll bet you would find ways to waste not a drop, as water is heavy. I have a friend who grew up in a village in Africa and she knows how to take a “shower” in one gallon of water. When you must carry your water and then collect sticks, dried cow poop, or whatever to burn for heating the water, you likely won’t take 30-minute showers. I’m just guessing that when she was a child, people in her village would have found flush toilets amusing and stunningly wasteful.
We take eight-minute showers here on average. Even with a low flow showerhead of 2.5 gallons per minute, that’s twenty gallons, or just under 167 pounds. The average American house uses 300 gallons daily, or just over 1-1/4 tons of water. Imagine carrying that home on your head or shoulder! Of course, there are highly technical ways to use less water, like is done on the Space Station. They use about 3.25 gallons per person per day up there because, guess what, water is heavy and transporting it to the Space Station is astronomically expensive! Water is collected from the air, from urine and probably other places, then cleaned up and used again. Hmmm. The least technical and most inexpensive ways of using less water have the benefits of being simple and durable. A real low flow showerhead has little to go wrong, other than hardness buildup. Smaller diameter, shorter pipes hold less water, so will deliver hot water faster with less waste. Toilets that use no water at all could save nearly 30% of your total indoor usage. Just like the most efficient light bulb is one that’s turned off, finding ways to eliminate water usage is a good first, money-saving step.
We understand the meaning of being off grid as it relates to power, but how about being off the water grid? What would it take to live comfortably with only the water our property could generate? There is a lot of interesting technology available which could allow us to cut our demand for water 90% or more. With such low usage, we could consider “water from air” devices instead of digging wells or hooking up to the local water company. I remember reading long ago in “Ripley’s Believe it or Not”, that some fishing villages used to string nets by the shore to collect fog and drip it down into catchment basins. That sounds nicely low-tech, durable, and cheap! I believe we have far more efficient devices now. Of course, we’ll need to see how they hold up over time.
Fortunately, water is the ultimate recyclable material. We can recycle it to our gardens or toilets. With a little more tech, such as distillation, we can turn it back into drinking water, so nearly no new water needs to be imported. All the water on Earth is recycled! Earths’ purification systems work very well to give us water that we can safely use. You have certainly had the same water molecules passing through you that some T Rex of long ago called his. That water has been recycled many times!
Historically, entire civilizations have had to leave their lands in times of extended drought. If we ask what we really want of our hot and cold-water service and combine it with new technology and ideas from elsewhere, perhaps we’ll get a glimpse of our future where we can have true water security. Now that’s comforting!
I'm a fan of mind maps. They help me put all the aspects of a complex project down in one place. This writing is much more intuitive and natural than trying to write a linear outline. The only problem with it is that once written, it often doesn’t fit nicely on a normal page! So, here’s what started life as a mind map, but I’ve converted it to outline form, so you can read it! The central theme of it is the title. From there, each bold heading is a category linked to the title. Likewise, there are sub-categories or thoughts related to each category. Enjoy!
Definition of Simple Solar
Passive (no, or few moving parts. No electrical usage)
1. Large diameter piping in attic
An active lid makes it far more efficient.) It could be placed on…
Let’s start with a little background. A dip tube is simply a pipe inside of a water heater tank, which delivers cold water from the connection on top down towards the bottom. Hot water floats on top of cold water; that’s called stratification. If a dip tube cracks or breaks off, cold water can mix with the hot, higher up in the tank, de-stratifying (mixing) the tank, so that you get a luke-warm shower, or worse! Keeping cold separated from hot is the dip tubes’ main function. It allows 70 to 75% of the water in the tank to be used as undiluted hot water. The reason most heaters have dip tubes instead of simply hooking up the cold inlet at the bottom is that it's safer (and easier to install). What makes it safer is that if the main water supply line breaks, a bottom connected tank could empty, making for a dangerous situation when the tank starts reheating. A properly working dip tube will leave the tank mostly full of water because there is a small hole drilled into the upper end of the tube that breaks a vacuum, by letting air in, eliminating the potential for trouble. You really don’t want your heater firing up with little or no water in it! In best case, it will ruin the tank, worst case could be an explosion!
Non-metallic (or plastic) dip tubes are used in modern heaters in part because they withstand corrosion and do not accelerate rusting of the steel tank. There have been problems in the past with plastic dip tubes failing, but there days, they hold up pretty well. Modern dip tubes are colored blue, to differentiate them from the prior generation of dip tubes which were white.
Dip tubes also come in a variety of configurations. They may mix water in different ways or create a swirl at the bottom of the tank to stir up sediment. My favorite approach is to use a curved dip tube along with a full port ball valve as the drain on the tank. When you open the drain, water rushes down the curved dip tube, and stirs up sediment, helping it to be flushed out of the drain.
Strange things can happen regarding dip tubes. Sometimes the plumber hooks up the hot and cold lines backwards. When this happens, you get a lot of warm water, but it never gets hot enough to be useful. Rarely, the dip tube is installed in the wrong port on top of the heater. This creates the same problem. Sometimes, the dip tube is just missing. When that happens, you get only a little hot water, and then it cools down, making for a quick and unpleasant shower! All this is reason to look at any heater closely before hooking it up, to make sure things are where they should be.
I’ve dealt with lots of complaints of insufficient hot water, but there are multiple causes for the complaint. It can be a crossover in the plumbing, where cold water can get into the hot side, or the recirculation line doesn’t have a working check valve, or the dip tube might be damaged, creating the problem. Sometimes a couple of things go wrong at the same time making the diagnosis and fix more interesting! A really simple way of determining if it’s a dip tube problem is to just feel (carefully) the hot water pipe leaving the tank. Say you’re getting a cool shower. When it happens, have someone feel the hot outlet pipe to see if it’s hot or only warm. If it’s hot, the water heater is working as it should and cold water is mixing in somewhere downstream. If it’s just warm after only a few minutes of running, you know there is a problem with the water heater and the first thing to look at is the dip tube.
And this brings us full circle. You want to know the dip tube is in place and in good condition so that you get that long, satisfying shower. If you’re not getting it, domestic tranquility is at risk, which won’t do! So, the takeaway is that a good dip tube contributes to peace in the house!
This is a question that never seems to get answered. I’ve only had to deal with it for about forty years, but it’s a far older question. It really has been around since water heaters first became automated around 1868, when an Englishman, Benjamin Maughan invented the first tankless water heater.
To start, I think we’ve been asking the wrong question. What we really want is the service of hot water in the most affordable, and easy to live with way. So, the question shouldn’t be about what technology is superior, but what technology meets my needs best. And the water heater is just one small part of the hot water system. The system itself affects the decision of what’s the best heater to use.
Most water heaters get replaced on an emergency basis. Heaters just love failing on holidays and when you have company. That’s the wrong time to figure out how to change things for the better, so most of the time a similar heater is slapped in place and promptly forgotten for another ten years.
I like the idea of having in mind all the things that would make your hot water system simply fabulous! It would give you hot water very fast, it would waste very little water, it would be silent yet provide good flow. And it would be inexpensive, durable, and simple to maintain. Okay, knowing those things, we know we want efficient fixtures and low volume plumbing. These things can save water and give fast hot water delivery, while making water scrub the lines to keep bugs and biofilms from growing in the system. Modern piping materials like PEX and lead-free fixtures will add very little contaminant to the water. Placing the water heater close to the rooms that use hot water will shorten plumbing runs for faster hot water delivery. Checking to see what fixtures even need hot water could simplify the hot water system as you discover that the clothes washer and dish washer might be able to heat their own water. Maybe some sinks don’t need hot water either as hand washing with room temperature water isn’t a big deal. Then point of use heaters can be considered for fixtures far from the main heater.
All of this matters because it allows you to modify the system as needed over time to make it easier to live with, while performing better. It gives you a plan moving forward. Maybe when you must replace your heater, you’ll discover that just by installing low flow showerheads, you can install a smaller water heater. And when you decide to do that remodel of the kitchen, you’ll know that you’re going to install smaller diameter PEX tubing to get better performance, and maybe skip that hot line to the dishwasher.
These things all make it easier to know what sort of heater you want to have. Tankless heaters offer endless hot water but the only place where I know we need endless hot water is with some industrial processes. In homes we use hot water not that many minutes of the 24-hour day. In homes, what we need is enough hot water. Tankless offers greater energy efficiency. Well, that depends on what technology it’s being compared to. Well insulated, condensing gas, or heat pump tank-type water heaters are hard to beat. Older, poorly insulated, atmospheric draft heaters are easy to beat, but still, they have little to maintain, unlike tankless heaters, so can wind up costing no more to own than tankless.
I like to match technology to the people who live there. An engineer might enjoy tinkering with the system, but a busy mom, not so much. Historically, we do not maintain water heaters or equipment in the home, even though we are told to do so, and warranties sometimes depend on our doing it. Complex equipment, like a tankless heater is more delicate with so many ways to fail. And the design of some equipment just baffles me. Have you ever seen the electronics of a modern heater placed under water connections? This way when there is a leak, it lands on the electronics, killing them. Why do they do dat?
Tankless does have a place. Glass lined tank-type heaters can give you smelly water if they sit unused for too long. Churches, vacation homes and any other places that have intermittent use are more prone to having the odor problem. Tankless units help you to avoid this problem as they don’t have much stored, stagnant water. A single faucet, far from other hot water uses can be a good place for a tankless heater. A big tub is a great place to consider tankless as it means you can use a normal sized heater for the rest of the house and still have the capacity to fill or reheat that tub for occasional use.
Oversold is a term usually used around stocks, but it can also apply to tankless water heaters. We are told about benefits that we don’t need, like endless hot water and how efficient the units are, compared to what…? We aren’t told about the high cost of yearly maintenance or the limited warranties, or that getting hot water in winter might be more difficult because of lower groundwater temperatures. My point in this is to point out how important self-education is in making sure you wind up with the right system for your needs. Ask good questions. Look at your own needs and wants. Make a plan that fits. And don’t be swayed much by other people’s enthusiasm for what fits their needs, for their needs and yours are probably not identical. I have no doubt that good ol’ Ben Maughan would not be displeased with your decisions even if it meant you didn’t use on of his heaters.
This is the story of some troubleshooting I was called to do. A tenant had complained to the local health department about his landlord. I was asked to investigate and then write up a report for the health department. Following is the essence of what I wrote up. It’s not quite a murder mystery, but getting there.
On October 20 I received a call from the Landlord to investigate water problems in his rental downstairs. In my work, I troubleshoot plumbing problems. Also, I occasionally teach classes that include how to troubleshoot. On arriving and talking to the tenant, I was told the sewer had backed up and flooded part of his apartment. What I discovered on investigation, however, suggested a fresh water leak.
The only suspect source of sewage would be from a floor drain in a utility area next to and lower than the apartment floor. In this area is a gas fired water heater. For sewage to flow into the living area it would have needed to rise high enough to soak the insulation in the heater and extinguish the pilot light. Neither of these things happened. There was also no odor or discoloration as one would find with a recently backed up sewer. There clearly had been a quantity of water in the apartment. The toilet flush lever had been snapped off. To operate the toilet, people had been reaching into the tank to lift the flapper. The lid to the tank was in a trash can rather than on the tank. Also, a string had been temporarily tied to the flapper to lift it, but had come loose. I found the base of the fill valve was wrapped in green electrical tape and the valve was not straight as it should be in the tank, but tilting off to the side. Additionally, a hairline crack was found in the base of the valve. Directly above the fill valve, a hole roughly a foot and a half in diameter was in the plaster ceiling. This hole was under a toilet upstairs, but I found no evidence of that toilet leaking recently and learned that the upstairs was unoccupied and locked during the time of this incident. It was found by looking at the water meter, that substantially more water had been used for the billing period than would be normal. Taking into account that the Landlord had been gone much of that time, the usage should have been less.
Putting all these pieces together I’ll suggest that what really happened is this: The plastic toilet flush lever was snapped off. The tenant, or a friend of his rigged up a string to operate the toilet. Either in working with that string or in reaching down to the flapper once the string had let go, the tenant or a friend cracked or otherwise damaged the fill valve. It let go and sprayed a jet of water up into the ceiling of the bathroom until someone noticed and shut off the water. Excess water flowed to the drain in the utility area. The fill valve was then “repaired” with green electrical tape.
It is outside of my expertise to speculate on why I was told this was a sewer leak when the evidence clearly suggests otherwise, but I hope this helps you to reach a just conclusion.
I later learned that the tenant had not paid rent for some time and had attempted, in various ways to get local government to find fault with the Landlord for improper maintenance of the property, claiming it to be unsafe. Ultimately, no fault was attributed to the landlord, but this experience caused him to stop renting the apartment in an area that has long had a housing shortage. The only moral to this story that comes to mind is to perform a very thorough background check on anyone before handing the keys over to your rental. I suppose you could add that “facts speak louder than words”.
...who just loves to call me when there is some strange hot water problem to troubleshoot. Fortunately, we always seem to find answers. Sometimes troubleshooting involves finding what isn’t there, because simply noting what is there doesn’t really give you enough clues about what’s wrong. Sherlock would be proud!
That’s sort of what one of his jobs was like a while back. Sometimes the pump moved water. Other times it didn’t. Was it in the controls, or out in the piping, or? It looked like an air trap, so we fixed the piping to eliminate that… no luck. We tried bypassing controls… no change. We took things apart and flushed out all the piping, one piece at a time. It seemed to work and then it didn’t! The final bit of work gave us a useful clue. It worked fine with cold water, but when it got hot, it quit. Ahhh! It must be a thermostatic element in the piping. Close, but not quite right. It turned out the wrong type of element had been installed for this particular use.
They didn’t even have all these different types of thermostatic elements when I was out there every day, putting this stuff in. But things change. That’s a given. What was demonstrated on this job was when you eliminate all other possibilities, the problem is left there alone in the lineup, staring back at you. It had looked like some soft rubber had gotten into the line because when the pump didn’t work, water could still flow under street pressure, but the small pressure the pump created couldn’t move water. Flushing the pipes was the only way to be sure that wasn’t the case, or if it was, the rubber or whatever would have been flushed out.
This story reminds me why I’m a fan of simplicity, who is our friend. Complexity is not our friend when it comes to plumbing or buildings! It confounds and confuses us. It uses its tricks to deceive, and we don’t know what all of those tricks are. It seems to take pleasure in doing these things at the worst possible times, so they’ll cause the greatest disruption.
Just to be clear, the number of possible interactions increases as the square of the number of parts. One part = one action. Two parts = four. Three parts = nine interactions and so on. Then throw in time for corrosion and wear to happen, water hardness, user mistreatment or neglect, someone turning a wrench who should have been in a completely different line of work, and you begin to get a picture of why I like simple. Elegant simplicity is even better, but harder to reach.
My friend keeps me on my toes, and I’m grateful for that, even if I have to get out the oilcan and lube my brain occasionally.
Well, it’s not really the plumbing that needs to stay healthy, but rather the people who use the plumbing. It’s not a bad idea to keep the plumbing in good shape too. To me, healthy plumbing is a system that delivers enough water at the temperature you want, whether hot cold. It delivers clean water, without bacteria, viruses, metals, sand, or other stuff. It delivers hot water fast, without much energy or water waste, and gives you cold water quickly as well.
The piping system shouldn’t cause other problems, like expansion noise in the walls, or velocity sounds. It’s good if it doesn’t sweat, dripping water down onto sheetrock ceilings. It should be installed so it is safe from rodents and does not give them passageways to travel around the structure of the home.
So, let’s have a look at this list and see what to keep in mind:
Having enough water. This is a function of pressure and the sort of fixtures you have. Normally, pressures between 40 and 60 psi are what we want. Anything much lower can cause insufficient flow and too high can stress the plumbing system, or make water hammer a problem. Check pressure with a gauge that screws onto a hose bibb. I like to use a 0-200 psi gauge, and measure when no water is being used. It’s not much fun when you’re in the shower and somebody flushing a toilet causes the temperature to change quickly! Using “pressure compensating” showerheads and aerators will go a long way towards keeping flow the same, even with varying water pressures.
Pipe size matters too. If the pipe is too small or became too small by filling up with rust or scale, you won’t get adequate flow. Generally however, codes have made us put in pipes that are far too big for the ever-reducing flows we have in our homes. We used to have much higher water use fixtures than we do now, so flow rates continue to drop, but plumbing code hasn’t kept up. At present, they’re about sixty years behind reality.
The right temperature. This is a tricky one as hot water temperatures that are comfortable for people are also good for growing bugs like legionella in the plumbing. Temperatures that kill off the bugs will scald people pretty fast. For people not too old or young, and in good health, 130 degrees F is usually a good place to set the heater to, as it doesn’t promote bacterial growth and doesn’t burn people that quickly. Modern, pressure balanced shower valves are absolutely worth putting in as they help prevent rapid temperature changes in the shower. Another approach that’s becoming common is to install a tempering valve downstream of the heater, so you mix down hotter water to a safe 120 degrees or so. Even this approach could let bugs grow in the piping, however. As I said, this is a tricky problem! Having cold water stay cold and not sweat and drip condensation is a concern for humid areas. It may seem counterintuitive, but insulating the cold lines is a good way to prevent problems here. Pretty simple! Of course, all the hot lines should be insulated too.
Clean water. This one matters! Think of Flint, Michigan. We don’t want bugs, metals, chemicals, or other bad things in our drinking water. Pipes that are too big, or have unused portions called “dead legs” in them are the perfect breeding grounds for nasty bugs. Sizing the pipes so you get at least one foot per second of water flow through them helps scour the pipes, preventing bugs from having a place to hang out. This flow also keeps sediment from being able to settle in the lines so much.
About metals, we need water that is not corrosive to the piping material, and we need materials that don’t contribute to the problem. With older faucets, it’s common to have way too much lead in the first flush of water in the morning. Particularly if the water is acidic or over-softened. Older faucets had lead in them to make machining the brass easier. We’ve learned a little since then! Lead was often used in the supply system to connect branch lines because it could flex. There are better ways to fix that problem now. Debris can simply be flakes of rust from steel piping or silt from wells, or other stuff. Fortunately, it’s not hard to filter this gunk out, but be sure to keep the filter clean and out of the sun or it could become another source of bugs and algae!
Energy and water waste. This one gets taken care of with good piping layout and sizing. Recirculation lines that run 24 hours can triple your water heating bill… and they damage piping. The basic idea is to put in pipes that are only big enough to give you enough water and no bigger. They should be kept as short as can be done. This all creates low volume plumbing, so less water must be flushed out to get hot or cold water. Interestingly, if you have a gallon in the lines between the heater and tap, you’ll have to waste between one and a half, to two and a half gallons before getting hot water. That can be a significant waste of water, energy, and your time! So, see if the water heater can be put close to the fixtures to shorten the piping runs and then keep the pipes as small as you can.
Other problems. I’ve covered sweating pipes, but not touched any rodents! Plumbers sometimes seem to enjoy drilling rather large holes in the framing to run their pipes through. The mice like this! It gives them easy access from crawl space to attic. Sometimes you can hear them behind your headboard at night, partying! Rodents don’t use toilets, so things get a bit unsanitary. The hantavirus is not something you want the critters to give to you. Rats are smart. They know water is in those lines. If you’re using plastic lines, like PEX, that rat just might chew through the line to get a drink. I’ve seen it happen and it’s not something you’ll discover right away. The wood framing that’s getting sprayed could rot and need to be replaced and then there is that big water bill. This problem can be avoided by running small plastic lines in bigger conduit, when going through crawl spaces or other places rodents can’t readily be kept from. It’s a bit of a pain to do, but far easier than dealing with the problems that come of not taking that precaution.
Expansion, water hammer, and velocity sounds are the last things I’d like to touch on. Metals expand a little when heated and plastics expand a lot more. When installing copper pipe, it’s good to use plastic bushings when going through wood, so there is a way for the pipe to move quietly, rather than rubbing hard on the wood and making creaking or popping sounds. Soft plastics like PEX can be installed so that they can bow out a bit when heated by the hot water inside. PEX tube expands and contracts one and one tenths of an inch per 100 feet, per 10 degrees F change in temperature. So, if it goes from 50F in your crawlspace to 130F with hot water, that’s an expansion of 8.8 inches per 100 feet. Where’s that extra pipe gonna go? It’s a good thing for the plumber to keep in mind.
Velocity noise happens when water is moving too fast through the lines or fixtures. This could be the result of a reduction in size caused by corrosion where different metals meet. For example, where copper and steel meet, the steel rusts, reducing the path for water flow. Valves may get hard water build-up inside and hiss when running water. Good clean water, good piping design, pressure control, and pipe sizing will go a long ways towards quieting these things down.
Water hammer is what happens when water is moving fast down the line and is made to stop quickly, by closing a valve too fast. It’s more of a problem with the combination of too high a pressure combined with fast closing automatic valves, like you find in washing machines or dishwashers. If simply controlling water pressure doesn’t fix it, then water hammer arresters can be put just in front of the valves that are causing the problem, and that gives a cushion for the water to hit, rather than a brick wall, as the valve closes.
I’ve only touched briefly on some of these things… a book could be written, but hopefully you see how each part affects other parts of the system. The human component is the most variable one, and sometimes doesn’t obey the laws of physics like the rest of the system does, but we adapt 😉
Although I don’t go as far back with solar water heating as Day and Night Solar, I am one of the old guys in the field having built my first system in 1978. I installed new solar right up to the end of tax credits in 1986. Then 90% of the solar companies in my area vanished and I took on keeping all those local orphan systems running.
What I saw taught me a lot about how not to do solar. People had installed copper coils in galvanized tanks. This caused the tanks to leak within a year or two. Some installed the solar tank downstream of the electric “backup” tank, so electric was heating the solar tanks. Just imagine that meter spinning! Drainback systems were put in so they couldn’t really drain back, and pipes froze. The wrong insulation was used and would melt off the pipes, or no insulation was used at all, or was sloppily installed, so it didn’t really work. Pumps would come on during freezing weather, so pipes that would have been fine, burst because of controls poorly set up………
I saw systems so complex that it took a longish time to figure out what the installer might have had in mind. Systems like these reminded me of being inside of an older style diesel submarine with pipes running everywhere. Perhaps the installers were proud of these systems because it was common that they had no insulation… probably to show off all the shiny copper piping! If you’re going to have a system like that, you need to build a separate bedroom for the installer as he or she will be spending a LOT of time at your place. At least put a cot in the mechanical room!
So, I got to learn a few things. First is Elegant Simplicity. This matters because the more complex something is, the more ways it has to misbehave. Just think of the interactions between parts. If there were only two parts, that’s two interaction. Three parts means six interactions. Four parts means twelve interactions, and so on. Keeping things simple, by actually putting the properties of the materials to use, is a great way to build a durable system. The only problem is that it requires thoughtful design. I had the pleasure of working with Steve Baer, of Zomeworks in New Mexico. He was a champion for the practical application of elegant simplicity, and he wrote a lot of good things too. The book: “Sunspots” is likely his best-known work. If you want durable and efficient systems, elegant simplicity is THE way to go.
It’s also useful to study the history of solar, so that you understand the ideas that have come before. See if you can find a copy of “A Golden Thread: 2500 Years of Solar Architecture and Technology”. It’s a fun and useful read! It also makes sense to design systems that are a good match for the people living there. A very complex system might be fine for the plumber or engineer who likes to tinker, but not so good for the busy professional who works primarily with their mind, rather than their hands. I learned that most people ignore maintenance, so it becomes important to design systems that may only need to be seriously looked at about every five years. That’s hard to do. Also, they need to be designed to fail in a safe way, rather than failing so water leaks out or steam from stagnant collectors fills the garage!
One of the most common systems around the world is the thermosyphon type. It places the storage tank above the collectors so warmed water flows by convection from the collectors up into the tank. Having no controls or pump to fail is simpler! Even so, that type of system doesn’t do well in cold climates, but there is no need to have only one system type to cover all areas. There might be places where photovoltaics should power a heat pump, just because any outdoor plumbing is risky.
Leaving the past for a bit, I’ve more recently built systems that come pretty close to being simple and perform far better than conventional solar, along with costing about half as much. The key to doing this is to not look for the most efficient collector, but rather, an inefficient collector! By having more square feet of inefficient collector area, you get more BTUs and eliminate the risks and design challenges of overheating. By using the right type of plastic collector, you nearly eliminate the risk of freeze damage. Also, the collectors cost less and are even something that a handy person could make themselves. Add to this, using a well-insulated plastic storage tank and “too much” insulation on the lines allows this system to take care of 90% of the user’s hot water needs! Also, there is very little to maintain. Not bad! A normal “good” system can do 70 or 75% and many do far less. Throw in a little efficiency in the plumbing distribution and fixtures and you will be able to take long, luxurious showers and still be efficient!
I’ve only skimmed over the topics of history, design, and efficiency. Still, I hope you understand now that solar thermal can be done well and cost effectively. It does not need to be relegated to the dust bin of history. But, it must be done thoughtfully to work well, long term.
Looking back over my working life of 50+ years, it seems clear that self sufficiency has always been the best way for me to be useful. Now, mix in a strong interest in water in its many forms and the wide world of animals and you'll know what's important to me.