July 2015

Heating and Cooling21 Jul 2015 04:45 pm


I have a new toy: the Lasergrip 1080 infrared thermometer. It can measure the temperature of anything you point it at, with incredible accuracy. This winter it’s teaching me all kinds of things about the temperatures of the walls, ceiling, windows and floors of my house.

The most interesting insight is the strong evidence it has provided of the effectiveness of the draught stoppers beneath my doors. Take a look at the two photos above, taken at 7:30 this morning. The floor next to the door with no draught stopper—I removed it before I went to bed for this experiment—is more than 3 degrees Celsius colder than the floor protected from the cold air blowing under the door. Three degrees is a big difference when looking at indoor comfort.

I put that draught stopper back on right away.

Recycling14 Jul 2015 04:11 pm


My poisonous pile

My office is piling up with the victims of loadshedding: failed gate-motor and alarm batteries that were never designed to be fully depleted so frequently. When I complained to a salesman that my latest gate-motor battery had lasted only 7 months, he suggested that I be grateful; some of his customers were replacing their batteries every month.

These 12 volt, 7 amp batteries are made with poisonous lead, just like car batteries. They should be kept out of the landfill and sent for recycling. Besides, the lead has real value, especially since lead is one of the few metals that South Africa has to import. But since I was uncertain where to take them, I let these heavy, black bricks accumulate over the past few years until I had a stack of eight. The time had come to learn the best locations for lead-acid battery recycling. Actually, they were easy to find, and some even pay for used batteries.

Pick n Pay stores commonly have recycling bins at the entrance, including one for batteries. I phoned Uniross, which handles the batteries collected in these bins and learned that ordinary alkaline cells are not recyclable, but can be left in the bins for safe disposal. Small lead acid batteries like mine will be recycled. For more information on other battery types, click here.

Automotive suppliers that sell car batteries are legally required to charge a deposit on the batteries they sell and pay a deposit on the car batteries they receive. Alas, the two local branches I phoned of Battery Centre and Midas would not offer to pay for my lead-acid batteries, but they would take them off my hands. The staff who answered the phone gave me pause with their comments: “I’ll help you get rid of them,” and “They get disposed of safely.” But since these suppliers are regularly shipping car batteries for recycling, I have a fairly high level of confidence that smaller lead-acid batteries would also end up in the right place.

First National Battery has a battery recycling plant in Benoni. If you drop off at the facility, they will pay R4/kg for any lead-acid battery. My eight batteries weigh about 17kg, so they would be worth R68. Unfortunately, I live too far from Benoni to justify the time and emissions of traveling that far. For more information call 0800 333 462.

Scrap metal dealers pay even better prices. I spoke with Maningi Scrap Metals in Marlboro, Johannesburg, and their price for lead-acid batteries is R7 a kilogram. One comfort in selling the batteries rather than dropping them off is that the buyer has a financial incentive to make sure they are actually recycled.

But for the best balance between confidence and convenience, I’m dropping my batteries off next time I shop at Pick n Pay.

Appliances &Heating and Cooling07 Jul 2015 03:39 pm

Rinnai gas heater with thermostat set on high ©  2015 Don Boroughs

H is for ‘Hopelessly confused’

You like to cook your egg on a medium stove heat, but to get the pan warmed up you first set the electric hob to high, right?

You arrive at a Kruger Park rondavel on a sweltering day and turn the temperature control knob on the air conditioner thermostat as far as it will go to cool down the room more quickly, right?


You use thermostats every day. Do you understand how they work?

A just-released study of American homeowners reported here found many misuse their heating and cooling thermostats. A third of them seem to not understand how thermostats work at all.

Central heating and air conditioning are much less common in South Africa, but thermostats still govern our stoves, ovens, geysers, portable heaters, and room air conditioners. Use them incorrectly and you could be wasting energy.

I see the confusion in my own home. My Rinnai gas heater has two heating levels—high and low—and a thermostat with temperature settings from 16 to 26. The H setting above 26 means it is kept on high heat even if the room gets hotter than 26 degrees. Since no one really wants to be that hot, I should never find it turned up to H, but that’s frequently where I find it set.

The culprit who set it on high could have chosen 21 instead, for example, and as long as the room was colder than 21 degrees, the thermostat would have kept the burner on high heat, only switching down when the temperature reached 21 degrees.

The gremlins in my house and many other people and confused by the myth that a high setting on a heater, stove or air conditioners will somehow make the appliance work faster. Not so. The element in an electric stove or heater and the compressor on an air conditioner can only be on or off. A low setting on the stove allows your soup to simmer because the thermostat switches it on briefly and repeatedly.

Why does this matter? Because if you walk away or fall asleep with the stove on high and the air conditioner on max, you will waste electricity, burn your pan and shiver all night. Always set a thermostat to the final temperature you would like, then let it do the work of switching on and off. That’s what it’s made to do.