March 2011


Lighting30 Mar 2011 10:58 am

Not such a bright idea

What grown man would get excited to see a light bulb selling for less than R100? Me, if the lamp in question uses ultra-efficient light emitting diodes. LEDs are the future of lighting, with low power consumption and incredibly long lifetimes, but their high prices have kept consumers away.  So when I noticed a R94 rand Eurolux LED at my local Builders Express, I took a closer look and took notes. The last LED globe I had seen that was meant to replace a halogen downlight had a R372 price tag on it. Was this too good to be true?

Yes, of course it was. The packaging of the Eurolux LED is inexcusably devoid of technical information, except to say that it delivers 50 lumens, a rather useless piece of information for the average consumer. It turns out that 50 lumens is an equally useless amount of light, unless you are just looking for a decorative accent to highlight your teacup collection. A 50W halogen, the most common size of downlight, delivers about 10 times that much light.

Eurolux, a company from the Philippines—despite its name—has very good prices and is prominently displayed in many South African stores, but I do not trust their quality. I have seen too many Eurolux compact fluorescents fail while major-brand CFLs continue burning brightly. I buy almost all of my lighting supplies from Osram and Philips, and I believe the premium I pay for those brand names is compensated by their durability. (Eurolux, like Philips, does carry a three-year guarantee on their LED products; Osram LEDs are covered by a five-year guarantee.)

LEDs are falling in price, but for now, expect to pay R300 and up for a good-quality bulb. That may seem like a ridiculous price for a globe, but depending upon where it is used, LEDs can be a financially sound investment. According to Philips, Makro Woodmead and Strubens Valley and Pick N Pay Faerie Glen currently sell a 7 watt Phillips Master LED GU10 bulb for R299. My calculations suggest that over the course of 4 years, in a room where the lights are on 5 hours a day, this LED bulb is no more expensive than buying and using the equivalent 35W halogens at R40 each. After those 4 years, the LED pays a return on your investment. (The calculations ignore the cost of capital. You wouldn’t charge the environment interest, would you?)

If the bulb is in a location where it burns less frequently, it takes longer to pay for itself, and vice versa. At 3 hours a day, expect a 7 year payback; at 6 hours, the initial outlay is recouped in just 3 years. LEDs are improving rapidly, so the temptation is strong to wait. My advice is to buy a few now for a room where the lights burn longest, and gradually add more rooms as better and more affordable LEDs become available. Sometimes you have to spend a little to save a lot.

Solar23 Mar 2011 01:32 pm

GeyserWise GeyserWise Power Save Mode

GeyserWise . . . . . . not saving in Power Save Mode

As far as I’m concerned, my GeyserWise thermostat timer paid for itself within a few weeks. Then it started costing me money.

The GeyserWise is an electronic device that replaces both a timer and the thermostat on an electric geyser element. As I have stated before on this website, a timer is an essential part of a hot-water solar system. The GeyserWise would appear to be the ultimate geyser timer, allowing the user to set multiple programs to turn the geyser element on and off, to see the temperature inside the tank, and to adjust the thermostat setting from a comfortable position several meters away from the geyser itself. No more crawling into the roof space with a headlamp and screwdriver.

I paid R1300 for my GeyserWise, including installation by an electrician recommended by the manufacturer. Here’s how it paid for itself so quickly. Monitoring the temperature inside my tanks, I started noticing that the water would cool off by a few degrees in the late afternoon every (more…)