Appliances &Global Warming31 Jan 2014 06:32 pm

cooking test

Science, not Home Economics

The problem with too many environmentally conscious types is that they are scientifically un-conscious—too willing to believe any green claim made by advertisers. So I was very glad to find some fellow skeptics at the Eskom eta Awards: the girls of the Clarendon High School Coelacanth Enviro Club in East London.

Like me, these high school students were intrigued by a new type of stove, induction cookers, which promise huge energy savings. These devices use magnetic fields to heat a pan or pot, which must be made of iron or steel. The companies selling them typically claim that induction cooking uses half the electricity because it is faster than a conventional stove. The Coelacanth Club put these claims to the test.

Cooking a range of foods on both an ordinary spiral hotplate and an induction cooker, the girls found that the induction cooker reduced electricity consumption by 19 percent on average. The savings were high when intense heat was required: 33 percent for boiling water and 30 percent for deep-frying potato chips. For simmering, the savings were less impressive. In fact, the induction cooker was no more efficient than the spiral stoveplate when making fudge  (These girls were definitely not on a diet.)

I’ve crunched their numbers to get a sense of the savings in rands. If every day for a year you cooked their “meal” of boiled water, fudge, mashed potato, potato chips and creamy chicken, you would save R130 a year at a typical rate of R1.20 per kilowatt hour—and you would gain a lot of weight. Since induction cookers cost anywhere from R600 for the Prima brand at Makro to R1200 for the Snappy Chef brand used in the Clarendon test, it will take several years before the cooker has paid for itself.

There are other advantages to induction cooking, however. The pan reaches high heat levels much more quickly, saving time. The pan heats but the stove does not, so it is safer. Most models shut off automatically when the pan is removed, which will save ditsy cooks even more on their electricity bill. Finally, your cooking carbon footprint will fall, as long as you are not cooking fudge.

But the Clarendon girls found that for the ultimate in low-carbon stove-top cooking, gas is by far the best option. Preparing the same range of foods on a gas stove cut carbon dioxide emissions by an average of two-thirds. Greening your kitchen emissions by using to gas can be either cheap or expensive, depending upon where you live. The lucky Jo’burgers with access to Egoli Gas can save money compared to cooking on electicity. Unfortunately, for the rest of us, using bottled gas at the current price of R1225 for a 48 kg cylinder means paying 88% more compared to powering an ordinary electric stove.

More environmentally friendly meals can come without any pricetag, however, according to the Coelacanth Club. Their research shows that simple improvements in cooking techniques, such as using lids, simmering on low heat once food has come to a boil, and using only as much water as needed, can save about 40 percent of the energy required to cook more inefficiently.

The Clarendon Coelecanth Envio Club won the Young Designers category at the eta awards. And we have all won in the kitchen by learning from their efforts.

Uncategorized29 Dec 2013 12:45 pm


Accentuate the Negative

The image above is taken from my latest Johannesburg utility statement. The minus sign in front of Total Due signifies that rather than owing the municipality for my electricity and water, the municipality owes me. I would love to say that this is because I am producing electricity on my roof and selling it to City Power. That day is coming – slowly. It is, however, my reward for reducing electricity consumption.

I recently qualified for the LifeLine Tariff, which is available to customers who use fewer than 500 kilowatt hours a month. The rate that I pay for electricity itself came down only slightly, from R1.08 to R1.01 per kWh. The big difference is that I no longer have to pay fixed fees – Network Charge, Service Charge and Demand Side Management Levy – of R409 a month. In most months I was paying more in electricity service fees than I was for electricity. These mandatory charges create a perverse disincentive to save power. Previously, if I were to cut my consumption in half, my bill would go down by less than a quarter because of these fixed fees. Now I pay only for the electricity I use.

When I first enquired about the LifeLine Tariff, I was told that anyone using less than 500 kWh per month for six months in a row “automatically qualifies.” Nothing could be further from the truth. It took dozens of letters, emails and calls over the course of seven months to finally get my account changed on the system. The new tariff was backdated to the date of my application, which explains the credit that shows on my bill.

A prepay meter is another way to get out from under the burden of service charges. This comes with its own set of hassles, but is an alternative to the LifeLine route. If you are also a kilowatt-hour miser and have the patience to take on the bureaucracy, apply for the LifeLine tariff by emailing a letter with your account number and details on your consumption for the last six months to [email protected] If you first need to cut kilowatt hours before Jo’burg will throw you a LifeLine, keep reading Greener House.

Global Warming20 Dec 2013 12:13 pm


My article in this week’s Mail & Guardian looks at the economics of South Africa’s switchover from tin-plated steel to aluminium beverage cans. Coca-Cola and SA Breweries are already using almost 100 percent aluminium cans in Gauteng, and by 2015 they will be covering the nation with the shiny metal. Much of the story is on the business impact on the major companies involved, but I also examine the new environment for recycling.

The potential is both exciting and frightening. Here’s a brief excerpt from the article:

Aluminium industry expert Subodh Das estimates the value of used beverage cans wasting away in US landfills at $55-$80 billion—as much as the total annual turnover of BHP Billiton, the world’s largest mining company.

Perhaps worse, the energy wasted by not recycling those cans accounts for greenhouse gases equivalent to the annual emissions of a rather large country like Egypt or Argentina, 260-380 million tons of carbon dioxide.

In preparing the article, I worked very hard to come up with a carbon footprint for a single aluminium can made from virgin South African aluminium. Under deadline pressure I wasn’t able to work out the number with sufficient confidence, but I have since calculated that an unrecycled South African can contributes approximately 0.7 kilograms of carbon dioxide to the atmosphere. To put it in more tangible terms, the pollution released to make that can is like burning a 60 watt globe for 12 hours or driving nearly 3 kilometres. The vast majority of that energy is saved if the can is recycled. When deciding whether to toss a can, imagine it 85 percent full of petrol, because that’s the equivalent of the energy that went into it.

This example is a little bit hypothetical, because you will never know whether the can in your hand was made from virgin South African aluminium. Many of the new aluminium cans are made from sheet stock imported from Brazil, where 98 percent of cans are recycled. These will have a much lower carbon footprint. If South Africa can emulate their success, the carbon footprint of locally produced aluminium can stock will fall, and my calculations will become obsolete. I won’t complain.

Uncategorized05 Dec 2013 03:24 pm

Award Presentation to Don Boroughs

with Eskom Chief Executive Brian Dames and Group Executive for Sustainability Steve Lennon

It sounds clichéd to say that winning an award was a “humbling” experience. But there is no other word to describe the effect that the Eskom eta Energy Efficiency Awards had on me last night. Sitting next to me was the runner-up in my category of Energy Savings in Households, who lives in a house that uses about R75 worth of electricity in a month. (“Why doesn’t our house use that little?” my wife whispered to me.) After the ceremony, I was chatting with a woman who managed to not only save R170 million annually in liquid propane gas purchases at Arcelor Mittal’s Saldanha Works Plant, but in the process helped rescue the factory—with more than 500 workers—from closure. So, would you like to hear about my pool pump . . . ?

I was particularly impressed with Josephine Bröhm, a high-school student in Plettenberg Bay who has created a Facebook page  that encourages teenagers to negotiate with their parents to split any savings on their electricity bill and then shows teens ways they can cut down on consumption around the house. The same concept could work with a housekeeper, as well. I successfully implemented a similar project to split the savings on my water bill with my gardener a few years ago, which I wrote about here.

Eskom has videos of each project, and I have posted two here. The one for Greener House sums up my efforts nicely, though it bizarrely pronounces my name “Barrows.” The one for Rod McGregor Mann, the runner-up in the households category, shows off his funky, wind-powered house in the Eastern Cape. (He says that his Leading Edge wind turbine is extremely quiet.)

If you want to read more about the awards, check this weekend’s Mail & Guardian, Sunday Times, or



Recycling11 Nov 2013 02:30 pm

Aluminium can litter

Trash to treasure

Some people play bowls. Some collect ash trays. I pick up aluminium cans. It’s probably not correct to call it a hobby. Strictly speaking, I think it would be diagnosed as an obsession. But I had my life under control until a few weeks ago. Red Bull and Monster energy drinks were about the only aluminium cans scattered along the roadside, apart from the odd imported beer. I would return from a jog or a walk with a small handful.

The people at Nampak—in their wisdom—have changed all that for me. The photo above shows part of the haul from a single bike ride from Marlboro to Victory Park. (I dropped off my car for repairs and rode home using the bike I had brought in the car.) It was difficult to ride a full block before another shimmering aluminium cylinder caught my eye. Coca-Cola, Fanta, Castle Lite, Hansa, these were all packaged in tin-lined steel cans until about a month ago. Now they come in aluminium.

There is a method to my madness. No other beverage packaging has such a high carbon footprint and yet is so recyclable. This explains why each aluminium can is worth 9 cents to a recycler, while a tin drink can is worth less than 3 cents, even though it is much heavier. I have written about this before, here and here. The basic lesson is that compared to throwing away an old-fashioned steel beverage can, if you throw away one of these shiny lightweights, you lose at least 3 times as many points on that great big green scorecard in the sky.

There may come a time when street collectors recognize sufficient value in these cans to pick up the aluminium litter strewn about. For now, they mostly look for easier pickings. When I have a bin full of aluminium cans, I find a recycler on the street collecting metal and hand over my collection. I could more easily put the bag next to my wheelie bin on collection day, but I am selfish. The true satisfaction I derive from my hobby comes from seeing the face of the recycler when he takes possession of my treasure.

Appliances21 Oct 2013 12:11 pm

Russell Hobbs Kettle

Just one cup for me, thanks

As I have proven in a previous post,  the key to saving time and electricity at teatime is to heat only enough water in the kettle to fill the mug. But this is easier said than done. I’ve tried cajoling my family. I would occasionally remember to put a full jug of water near the kettle to make it easy to measure out a mugful. Still, I would regularly find half-full kettles of hot water, gradually cooling down for no purpose whatsoever. I never felt like we were making progress.

Then my wife unintentionally solved the problem by insisting that I buy the beautiful, speedy kettle that she had used at work. I was initially resistant but came to realise that an all-glass kettle  makes the water level instantly visible to anyone filling it. I have polled the family, and they all agree that it has virtually eliminated overfilling. Our kettle is a Russell Hobbs Illuminating Glass Kettle (model no. 15082), and it is incredible speedy and has dazzling,  blue LED lights, which serve no functional purpose but use a miniscule amount of electricity. We like this model, but the key conclusion is that any glass kettle makes it a lot easier to heat only the quantity of water you need. Clearly.

Uncategorized09 Oct 2013 03:10 pm

I have just learned that Greener House has been invited to the gala awards evening of the Eskom eta Energy Efficiency Awards. Well, the house won’t be going, but my wife and I will stand in for it. This means that our home will be announced as either the winner or runner-up in the category of Energy Savings in Households on 4 December. A photographer is coming to the house to document what we have accomplished for a video presentation at the black-tie event. Other categories include Industrial, Commercial, Innovation and Young Designers.

I had my doubts whether the judges would think Greener House had enough “wow” factor. Last year’s winner was a new construction in the bush, entirely off the grid. But I consider this home’s ordinariness to be its strength. It would be nice to have a straw-bale house with a roof made out of solar photovoltaic panels and a windmill turbine in the garden, but most of us don’t have that luxury. We have to make do with with we have, which in our case meant less glamorous changes that nonetheless reduced our electricity consumption by 75 percent.

Hold thumbs for us on December 4!


Appliances19 Sep 2013 11:51 am


True countertop cooking

What’s wrong with this photo? My egg is cooking on the granite, not on the stove. I don’t normally fry my eggs this way, but I did successfully cook this one entirely on the countertop to prove a point: turning off the electricity only after you are finished cooking is a waste of energy. My approach to cooking is like coasting in a car or on a bicycle. If an egg bubbles vigorously when cracked into a pan, I always turn off the electric hob right away, knowing that the residual heat in the pan and the stove plate will provide sufficient momentum to cook it through. The countertop experiment was an extreme case in which I had an overheated, heavy-bottomed pan.

The trick is not just for eggs. I often turn off the oven or the gas braai five minutes before removing food. (Don’t open the oven prematurely.) And the other day I brought Tiger Oats to a rolling boil on the stove and turned it off. The instructions said to leave the oats simmering on low heat for 15 minutes, but I ignored that advice and coasted my way to breakfast.

Heating and Cooling &Lighting &Pool &Solar11 Aug 2013 02:33 pm


The table above is a brand-new effort to show the results of everything I have done to make our house more energy efficient. It demonstrates that my family has slashed our annual power consumption by 74 percent over the past 16 years.  Taking this long view only became possible when I managed to get my hands on records for electricity use at this house all the way back to 1989. From that year until 1997—the year we took over the house—the average daily consumption was 52.5 kilowatt hours. This year, we are on track to use an average of 13.6 kWh per day. (If you want make your own comparison, every municipal utility bill in Johannesburg—and in most other cities—shows average daily kWh used.)

Moving under the 16.7 kWh/day mark has been a long-term goal for me. Households that use fewer than 500 kWh per month (16.7 kWh/day) qualify for the Lifeline tariff in Johannesburg. The main benefit of the Lifeline tariff is not the very small reduction of about 6 cents per kWh, but the total elimination of R362 in monthly service charges. These annoying fixed fees were often higher than the amount I owed for power used. The municipality has now approved my house for the Lifeline tariff, though I’m told “system problems” have delayed switching the account over. Assuming this is sorted out, I will be paying approximately R5000 total for electricity in the coming year, about R415 per month. If this house were still using 52.5 kWh per day, the annual bill at the latest Jo’burg tariff of  R1+ per kWh would add up to R25,850,  so I am now saving more than R20 000 per year.

What did it take to get here? There are a hundred small, permanent changes and at least a dozen actions I take every day to be vigilant. But I think the bulk of the saving come from a few major changes.

  1. Solar geyser in conjunction with Geyserwise timer. The chart shows a big drop in 2005, the year we installed our solar hot water panels and 2010, the year we connected the tanks for that solar heated water to a Geyserwise timer. There were other changes in 2005 and 2010, but I have no doubt that the investment in this system is the No.1 reason for our 74% reduction in consumption. For more information on my solar system, read here, and for more on the Geyserwise, read here.
  1. Non-electric heat. We have gradually weaned ourselves from electric heaters, and now rely exclusively on wood burned in a closed-combustion fireplace insert and a Rinnai gas heater in the lounge and dining room. For the rest of the house, we have warm slippers, down duvets, hot-water bottles, and passive solar heat through the windows. Click on any of the green links above to read more.
  1. LED lighting. The drop in consumption from 2012 to 2013 is almost entirely because of our switch to LED lighting. We had already been reducing consumption over the years with compact fluorescent globes and IRC Energy Saver halogen lights, but LEDs made the most dramatic impact.
  1. Variable-speed pool pump.  My .75 kW pump stopped working in early 2010, the same year I installed the Geyserwise and saw significant improvements at the electricity meter. I eventually replaced it with a Viron P300 variable-speed pumpthat uses a fraction of the power consumed by ordinary pumps.


I’m not satisfied yet. I think that 10 kWh per day is a reasonable goal for the next couple of years, if I can improve the efficiency of my solar hot water system, replace the last few incandescent globes with LEDs and perhaps start cooking on gas. When I reach that goal, I may just frame the chart and hang it on my wall.

Heating and Cooling19 Jun 2013 04:44 pm

Twin Draft Guard

The draught stops here

As a son of the American snowbelt, I have always been mystified by South Africans’ ideas about “fresh air.” I put these words in quotes because what a South African calls, “fresh air,” an American calls a “draught.” I see doors left wide open for minutes or even hours on frosty mornings. Friends sleep with their bedroom windows cracked open through the winter. When I first moved into my Johannesburg house, I was dumbfounded to discover that every room had a ventilation brick with holes to let in the breeze. My house was intentionally draughty.

I suspect that living in a house filled with fresh, bracing, 10 degree air is marvelously healthy for a family, as long as they are dressed warmly enough to prevent hypothermia. But this doesn’t seem to be how it works, because at the same time that people are letting all of this cold air into their homes, they are trying to keep warm with some sort of heating.

My nieces, who live in a home filled with north-facing windows and even underfloor heating in some rooms, say that they like my warm house. But the only advantage my home has over theirs is that I try to keep it sealed up like a submarine. I plastered over the ventilation bricks long ago. Windows are basically locked shut for the duration of the winter. Curtains are opened as soon as the sun strikes a window, but closed at sunset. Anyone who leaves a door open for more than five seconds knows they will hear me bellowing, “I can feel a cold draught!” from a room away. And I really do feel it. A door left open for just 30 seconds can drop the temperature of a house by several degrees.

I will acknowledge that at some point on a highvelt winter’s day, the outside air may be warmer than the inside. But this window of opportunity for open windows is shorter than you might think. Standing in the sun or driving in a car gives a deceptive impression of the outside temperature. This week, the temperature is predicted to reach 20° just once. On that day, the outside air may be warmer than the inside from about 1 pm to 3 pm. By 4 pm, the temperature chart falls off a cliff.

My latest victory as a draught resister was to purchase and install draught stoppers to plug the large gaps under my house’s front doors. I bought mine in America, but I have seen them sold by hawkers in Johannesburg at traffic lights. They consist of of two fabric channels, each filled with a long foam cylinder, one to block the two sides of a door. The foam can be cut to size to fit the door’s width.They have made a big difference in keeping my lounge warm through the night.

I’m not blind to the risks of carbon monoxide poisoning. If you heat your home with anthracite in an open fireplace, you need to ventilate. (Reasons not to heat this way can be found here and here. Likewise, inexpensive rollabout gas heaters should be used with a window cracked open. For the rest of us, if you need some fresh air in the winter, slip out the door quickly and take a walk.

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