Water Use/Greywater

Water Use/Greywater22 Jan 2011 01:55 pm

Throne contender Venezia

Long ago on this website, I gave my seal of approval to the Compact dual-flush toilet made by R.A.K. Bathware. (And blew a raspberry at a dual-flush toilet that does not work as advertised.) For nearly 6 years now, my R.A.K. Compact has flushed dependably well over 9 times out of 10, for both 3 litre half flushes and 6 litre full flushes. I had no expectation of finding a better toilet.

Over the holidays, however, I stayed at a house that had recently fitted Venezia toilets by Lecico, an Egyptian company. Using seemingly insignificant amounts of water, these toilets made absolutely perfect flushes. They were so perfect, in fact, that I sometimes flushed . . . uhhh . . . “solids” using the half flush. Officially, the Venezia is a standard water-saving toilet, using no less than the Compact, but this would depend upon the settings of the mechanism inside the cistern. I am certain that these Venezias were using less than 6 and 3 litres per flush.

This gives me some confidence that Lecico’s ultra-efficient Riviera toilet, rated to use just 4.5 litres for a full flush and 2.6 litres for a half flush, will function properly. The Riviera is also more attractive than the Venezia. But just to be clear, I have never used a Riviera and make no promises for it.

I priced all three of these toilets at Plumblink, and the Lecico Venezia is the cheapest of the lot. Packaged with a basin worth a few hundred rand, it costs R1175, excluding VAT. For the toilet alone, the R.A.K. Compact goes for R1139 and the Lecico Riviera will set you back R1195.

These figures are rather small next to the savings you can expect on your water bill. If you are replacing an old 9 litre toilet, a family of 5 could save about R625 every year at current Johannesburg water rates, R780 if you regularly water a large garden, bumping your bill into a higher tariff. Heavy consumers paying Cape Town’s higher rates would save over a thousand rand each year.  Our dual-flush toilets have already paid for themselves more than once.

By the way, most ordinary lever-handled mechanisms can work as a sort of dual-flush mechanism with a deft touch. Simply lift the lever back up part way through the flushing process for a D.I.Y. dual flush.

Heating and Cooling &Lighting &Solar &Water Use/Greywater29 Jul 2009 01:43 pm

Real Simple 1 Real Simple 2

The July issue of Real Simple magazine is now off the newsstand. So in case you missed it, I am reprinting my article about green renovations. The editors asked that the information be presented  as a series of questions for the various contractors that might work on a home renovation. I couldn’t really do justice to any of the subjects covered in that format and the space allowed, so I will try to expand upon some of them in future posts.

Crumbling house prices and economic jitters have convinced many homeowners that it’s safer to adapt what they have to what they need, rather than jump into a shaky housing market. But can a renovation help your house adapt to the planet as well?

Throwing a few photovoltaic solar panels on the roof won’t make your home green. And environmentally sensitive architects have moved beyond the singular obsession with energy efficiency. The catchphrase of green building in the 21st century is “embodied energy.” How much fossil fuel went into the bricks, cement, steel and glass that make up your house? What quantity of greenhouse gases is your home responsible for even before you switch on the first light? For some houses, the embodied energy of day one will exceed the sum of a few decades worth of electricity and gas bills.

Building in harmony with nature means working with the local climate, local suppliers, and even local soil. There is no one-size-fits-all solution. Instead of waiting for easy answers, start with the right questions. And if a contractor stares blankly at the ceiling in response to your queries, you may want to look for someone with greener credentials.


How earthy can our house be? Green architects agree that adobe, cob and rammed earth are wall materials of first choice for low embodied energy. An architect who has worked with them will know whether they suit your project. The biggest concern: banks will not approve a bond for new structures supported by such raw materials. A home renovation, however, may be able to get financing.

Can we aggressively pursue passive solar? The right combination of windows, walls and floors can supply most of your heating needs in sunny South Africa. But a large roof overhang is vital to keep the high summer sun out. If your architect cannot calculate the ideal overhang based on your latitude, orientation, roof pitch and height, find another architect.

Can we build around a wood stove? If you have a local source of sustainable wood, such as suburban tree fellers, a closed-combustion wood stove is the greenest way to heat. But with all of your warmth concentrated in one spot, careful designing is needed to help the heat reach colder parts of the house. Keeping the stove central to an open plan but away from any double-volume ceilings is a good start.

How can our home use nature’s air conditioning? Your architect should know how to take advantage of prevailing winds. Low windows on the cooler, south side of the house can draw breezes to force out summer heat from high windows on the north side. Drain the pool of heat on your ceiling with small, high windows that you can leave open all night without worrying about cats or cat-burglars. Transom windows aid the flow between rooms. Trees or shutters can shield western surfaces from the afternoon sun. Don’t let some sweet-talking salesman convince you into electric air-conditioning until you’ve given nature a chance.


Appliances &Uncategorized &Water Use/Greywater15 Nov 2007 06:18 pm


The 35 degree solution

For years I’ve had to avoid my wife, for fear that she would again ask me how long she must wait before I will replace our leaky, ineffective dishwasher. This Indesit was so old that the last few repairs have required salvaging used spares. I had been procrastinating that decision even though I knew that it would reduce wasted water and electricity. My procrastination had nothing to do with a fondness for mopping the floor or scraping crud off the bottoms of teacups. I simply feared the amount of research that would go into finding an energy-efficient, water-conserving dishwasher that gets dishes clean. I am happy to report that my new Bosch SGS44E12EU (also called the SGS43E02EU) arrived today, and the investigation was not quite as painful as I had anticipated.

Not that I got everything that I wanted. My first goal was to find a dishwasher that could make use of the spare hot water my solar panels produce for nine months of the year. Alas, a Bosch technical representative explained to me that no domestic washer has hot and cold intakes, and the intake valve on a Bosch dishwasher could not tolerate a temperature above 40 degrees. This would require me fitting an expensive mixer valve to cool the water before it entered the machine. Besides, he explained that the way modern dishwashers work is to start with cold water and gradually raise the temperature. Use hot water in the first cycle, he warned, and you will bake the food onto the plates. I gave up on that track.

The next step was to compare water and electricity usage of various dishwashers. In Europe, Australia and many other markets, this is a simple task. Each appliance is labeled with a large sticker showing energy consumption, water consumption and an overall A-G rating. Dishwashers in Europe get three ratings: one for energy consumption, one for washing efficiency and one for drying efficiency. The Department of Minerals and Energy has long been promising South Africans a similar system, starting with refrigerators in May of 2005. Two and a half years later, the only appliances with an energy labels are a few imports with their European label intact.

Still, through the Internet, brochures and the Which? website, it was possible to get information from overseas efficiency ratings. Bosch’s South African website, for example, clearly displays the European ratings and consumption data for all of its dishwashers. (Curiously, they don’t display that information for their tumble driers, which, like the vast majority of these energy hogs, get Cs.) All of Bosch’s dishwashers get European As for energy consumption, which means that they use less than 1.06 kilowatt hour for a standard 50 degree wash. Not coincidentally then, many dishwashers, including all of the Bosch dishwashers sold in SA use exactly 1.05 kWh. The one I chose also uses a modest 17 litres of water for a standard wash. The top-of-the-line SGS 46 E 28 GB uses a mere 12 litres. But it costs R6399, a full R3000 more than mine, which is a lot of money to pay to save the equivalent of less than a flush of the toilet.

More important, the upper-range dishwashers have 45 degrees as their coolest setting. The economical dishwasher I chose goes down to 35 degrees. My sister-in-law uses a Bosch similar to mine and says that she never moves it from that coolest setting. She doesn’t rinse anything before putting it into the dishwasher, and even sticky porridge bowls come out clean. I haven’t succeeded in getting the data from Bosch on the electricity consumption of a 35 degree wash, but I did my own calculations. Since it uses 1,05 kWh for a 50 degree wash, and since heating 17 litres of water by 15 degrees should theoretically require 0,28 kWh, the 35 degree wash should use approximately 0,77 of a kWh.

A while ago, I checked the consumption of my old dishwasher at home, using the same, moderately precise methods I used to check electricity lost to chargers, transformers, appliances on standby and other vampires. It used 1.35 kWh on its lowest setting and guzzled 35 litres of water. Worse yet, because it cleaned so poorly, we used many more litres rinsing dishes. This is a purchase my gardener will appreciate. (Why? See here.)

My dishwasher only gets a C for drying efficiency, but that’s because it doesn’t have the electricity-wasting drying feature. It should get an A+ for leaving that off.

If you want to read a good overview of dishwashing written with a sense of humour, check out the Appliance Advisor’s guide to green dishwashing. By the time you are finished reading it, you will be convinced never to rinse your dishes again before putting them in the machine.

But do you even need a dishwashing machine? Advertisements for dishwashers often claim that they use far less water and energy than hand washing. I’m not so sure. Washing carefully, with 5 liters of solar-heated rinse water in one sink and 10 litres of solar-heated soapy water in another, I could beat any dishwasher on energy consumption. But my new dishwasher is a big step in the right direction. And it’s a lot better for my marriage.

Garden &Uncategorized &Water Use/Greywater13 Nov 2007 10:44 am

For many of us in South Africa who are fortunate enough to be able to employ people to work in our homes and gardens, saving electricity and water must be a cooperative effort. I have installed the dual-flush toilets, the low-flow shower head and the indigenous garden. But when the garden water taps and kitchen appliances are largely in the hands of people who don’t pay the utility bill, how can we fully control consumption?

Six months ago, I launched an experiment to address this conundrum, and I am happy to declare it a success.

First an anecdote to illustrate how far apart my gardener’s mindset was from mine. Last summer, when we went away for two weeks, I took a chance that good rains would continue and shut off the sprinkler system. (I always shut it off in the summer whenever we have had 25 mm of rain in the past week.) When I returned to Johannesburg, I was delighted to see the city looking lush and green; I knew that my gamble had paid off. As I arrived at my house, however, I was appalled to find my sprinklers spraying full-blast. The next time I saw my gardener, he cheerfully reported that the day I left he had discovered that I had left the sprinklers off “by mistake” and that he had “fixed it” for me.

So when he later borrowed a couple thousand rand to buy materials to build his mother a house, I knew how I could help him pay it back. I showed him my water bills from 2006, and told him that we would follow the 2007 water bills and compare them. As long as the garden remained reasonably green, we would share 50/50 any money we saved on water.

The first change I noticed was that he was using a broom to sweep a brick walkway that he used to hose down. When he washed the car, he used a big bucket, instead of a running hosepipe. And where I had often found him watering parts of the garden that didn’t need it, he now asks first.

My water bills for the last six months have come down by an average of 38 percent, and my gardener’s debt has been cut by R670. I know that some of this is because the garden is more established now and needs less water. The good rains in October also helped. But I am convinced that a major reason is that we both share the same mindset now when it comes to water conservation.

I still have control over the sprinkler system, so the garden won’t go brown, and I know that he is too proud to let plants wither. But I have a hunch that the next time I shut off the sprinklers for a holiday, he won’t be fixing my mistake.

Global Warming &Pool &Water Use/Greywater15 May 2007 01:33 pm

Pool full of Coal

Winter is a tough time to hold down electricity consumption. Days are shorter so lights burn longer. The cold air begs for hot tea, hot meals, hot water, and hot electric heaters. (See this post on heaters.) Even solar-heated water needs an electric boost in the winter. But there is one easy place to save electricity as the days get colder: the swimming pool.

One of the best things anyone can do to make a greener house is to fill in the pool. Swimming pools waste water, use huge amounts of electricity, and require toxic chemicals. But my kids would kill me if I filled in the pool, and there are ways to mitigate the environmental cost of a pool.

The first priority is to get a pool cover that keeps out dirt and ultraviolet and prevents evaporation. If it’s a bubble cover, it will keep your pool warmer, too. In Namibia the law insists on pool covers to prevent evaporation. A cover will save thousands of litres a year.

Ultraviolet breaks down chlorine, which is why you have to add cyanuric acid to stabilize the chlorine. Put on a pool cover and you can save on both stabilizer and chlorine. Most important, with less dirt and more effective chlorine, you should be able to reduce your pool pump’s running time.

In most homes with a pool, the pump is the second or third largest consumer of electricity, after the geyser. If I followed HTH’s standard recommendation to run my pool pump 12 hours a day in the summer, and if I hadn’t resisted a sales pitch a couple of years ago to trade in my 750 watt pump for a new 1 100 watt model, I would be using 13 kilowatt hours a day to filter pool water, more than half my current total daily consumption.

Ignore HTH’s 12-hour guideline, and rather follow the suggestions of the California Swimming Pool Industry Energy Conservation Task Force:

Reduce filter operating times to no less than 4 to 5 hours per day during the summer and 2 to 3 hours per day during the winter period. This will reduce annual electrical consumption by 40 to 50 percent. Normal and heavier swimming use may require as much as eight or more hours filtration per day. Should water clarity or chemical imbalance indicate inadequate filtration, immediately operate the filter until acceptable water clarity has again been established. If additional filtration is still indicated, increase filter operating time in one-half hour increments until the water remains clear and properly balanced chemically.

I run my pool six or seven hours a day during the summer. Since cold water inhibits the growth of nasties, yesterday I reset the pump timer to three hours for the winter. Eskom struggles to keep up with peak winter demand in the morning between 6 and 10 a.m. and in the early evenings between 6 and 9 p.m., so make sure the timer is not set to run the pump during those hours.

All of this inspired me to do some calculations. A cubic metre of coal can produce roughly 3 000 kWh of electricity. My pool holds roughly 30 cubic metres. So if I kept a 1.1 kw pump running 12 hours a day year-round, as many South Africans do, the coal burned over 18 years to keep that pump going could fill the pool to the brim. Better a green pool than a black one.

Uncategorized &Water Use/Greywater28 Mar 2007 03:17 pm

Shower Head
Lio Gio

When I was a boy, my father installed a flow restrictor on our shower head to save water. Since we lived in one of the rainiest regions of the United States and regularly suffered from floods, I’m not sure why he felt compelled to do this. It must have seemed like the right thing to do. From that day forward, our shower trickled rather miserably, no matter how far we opened the taps.

So when I needed a new shower head a couple of years ago, I didn’t insist on a low-flow shower head. I was afraid of giving my family members an incentive to bath—using even more water—in order to avoid the trickle. Only when the sales person at Plumblink handed over the shower head did she mention that it was a low-flow design. In the intervening months, I have suspected that she was wrong. This shower head, a Lio Gio from Bossini, sprays with such abandon I could not fathom that it could be saving water.

Our shower water flows into the garden and the water is heated by the sun, so I don’t worry too much about shower water usage, and I hadn’t given the subject much thought again until I happened upon a U.S. Department of Energy guide to water-saving technologies. It said that switching from an older shower head, which would typically use 14 litres per minute, to a low-flow head could cut water consumption in the shower by two-thirds or more. Low-flow heads typically use 9.5 l/minute, but some go as low as 3.8 l/minute.

And the guide says they won’t leave you shivering under a trickle:

customer satisfaction surveys—such as the one undertaken by SBW Consulting for the Bonneville Power Administration—have shown that well-designed, lowflow showerheads provide showers that are just as satisfactory as those provided by older models with more forceful flows.

Inspired by this shower of information, I decided to take a stopwatch and bucket into the shower and find out what was happening in my house. At full force—a spray so strong that I would normally turn it down—my Lio Gio used 7.6 l/minute. That’s not the best you can buy, apparently, but still is below average consumption even for a low-flow head. Then I visited another house with armed with my bucket and watch to test an older shower head. It was using 15 l/minute, double my shower consumption.

There are many purchases you can make to save water. Buying water-wise plants to re-landscape your garden is probably the most significant one on the list. A new, efficient dishwasher or dual-flush toilet will also save a lot of water. But these are all fairly major purchases. If you want to start saving water—and the energy used to heat it—without spending much more than a couple hundred rand, the shower is a good place to get your feet wet.

Uncategorized &Water Use/Greywater14 Nov 2006 05:18 pm

Bad Toilet Good Toilet

                    Bad Toilet                             Good Toilet

Today I installed a new float valve in a toilet cistern that will allow me to “cheat” and fill the tank with 8 litres of water instead of 6 litres. Why would I want to waste 2 litres extra water on each flush? Because I’m already wasting even more water than that by flushing twice.

Anyone replacing a toilet should buy a water-saving, dual-flush toilet. These toilets use 6 litres of water for a full flush, but for “liquids” (that’s urine) they use only a 3 litre half-flush. But not all water-saving toilets are equal. It’s better to spend a little more and buy a quality toilet that you won’t have to flush twice. I learned the hard way.

For my house, I bought a dual-flush toilet make by R.A.K. Ceramics and sold by Plumblink. The model is called “Compact.” A year ago, it cost me R1474, which was more than I wanted to spend, but it works perfectly. I almost never have to flush it twice.

For my office, I figured I didn’t need anything quite so fancy. I paid about a third less to get a dual-flush Eton toilet from Plumb Crazy, now called Splashworks. Usually I have to flush it twice. Once I had to flush it four times, after manually adding more and more water to the cistern to top it up for a more powerful flush! My plumber assures me that it is working normally, but the design is poor. It needs a couple of extra litres to flush well. On his recommendation, I bought the new float valve to allow an 8 litre flush. He says that the problem was common with the earliest 6 litre toilets, but that some of the more recent designs work as well as older, water-wasting toilets.

Despite my troubles, I would never recommend that someone stick with an old water-waster. I figure we’re saving about 55,000 litres a year (6 people @ 5 flushes a day) in my house. At current Johannesburg municipal rates, that’s R542 a year. When buying a toilet, think of all that money you will be saving and spend some of it in advance to get a good one.

If you have a water-saving toilet that is working well—or not—let us know so that we can build up a list of recommendations.

Garden &Uncategorized &Water Use/Greywater15 Oct 2006 05:53 pm

Bathroom AtriumGreywater siphon in bathtub
It’s mid-October and we’ve had just one decent rain in Johannesburg in the last five months. I’m feeling desperate, but the atrium garden outside my bathroom is looking lush and green. Not because it’s been irrigated; I haven’t run the sprinkler in the atrium this whole year. The plants are living on bathwater. Two or three times a week, I open the window, plunge one end of my handy-dandy siphon pump into the water, and give it about five squeezes. The siphon effect takes over, since the garden is lower than the tub, and in 10 or 15 minutes, the bath is nearly empty and the garden is watered.

The entire cost of this fancy greywater system was R24.30, including 2 m of tube. The pump itself costs just R11.10. I bought it all from F A B Water Engineering in Randburg, but I’m sure these hand siphon pumps are available many places.
My only modification was to use a rubber band to strap a piece of metal (a small, throwaway spanner that came packaged with some DIY furniture) to the end of the intake tube. This weighs down the tube so that it sucks the water from the bottom of the tub. One day, I might buy a longer piece of flexible tubing for the outlet (I wish I had bought 4 m to start with), plug the end and cut various holes along its length to distribute the water around the atrium without ever having to move the hose.

Admitedly, the system only works if you have a bath, window and garden in a usable alignment. And it does require a bit more effort than just draining my bath. But it gives me great pleasure to share my bathwater not only with my wife, but with my garden.