By Harold Washington,2014-12-28 10:09
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    By using energy wisely, the consumer helps to keep costs down. This is called demand side management.

    In addition to the cost implications the growing population and accompanying demands on our energy resources have a severe impact on the country’s natural resources.

    The environment will benefit from the efficient use of energy. For example, every kilowatt-hour (kWh) of electricity saved means one less kilogram of carbon dioxide generated by a power station and released into the atmosphere.

    Energy saving tips

    Every household in South Africa can save electricity and money through the wise use of energy in their homes.


    ; Set thermostat of electrical geysers at 55 60 degrees C. Make sure the geyser and all hot water

    steel pipes in the roof are well insulated with fibreglass or even newspaper. ; Solar heating units could reduce the geyser’s electricity consumption by 40% to 50%. This would result in a saving of about 200kWh to 250kWh of electricity per month, depending on the number of geysers and the size of the family.


    ; Switch lights off when they are not needed.

    ; Use fewer bulbs with higher wattages. For instance, one 100 watt bulb produces the same light as two 60 watt bulbs.

    ; Dimming switches reduce electricity consumption.

    ; Use compact fluorescent lamps (CFL) instead of ordinary bulbs.

    ; Use low-energy lamps for exterior lighting.


    ; Use the correct heaters. Infrared electricity heaters are more efficient. An oil filled heater is the safest type of heater.

    ; Insulate the ceiling and seal air gaps in the home.

    ; Ensure that heaters have thermostats.

    ; Use electric blankets but turn them off when in bed.


    ; Fill the dishwasher completely before operating.

    ; Turn off before drying cycle and wipe dishes clean with a dry cloth.

    ; Connect the dishwasher to the cold water supply.

    ; Clean filters.

    Tumble Dryers

    ; Tumble dryers that operate with an electronic humidity control are the most efficient they

    automatically shut off the drying cycle when clothes are dry.

    ; Use correct temperature settings to minimize the amount of electricity used.

    ; Remove water before putting clothes into the tumble dryer.

    ; Utilize sunny days for drying clothes outside.

Automatic machines

    ; A front loading washing machine uses less water and costs less to operate. ; Use the warm water setting to cut down on electricity needed to heat the water. ; Make sure you have a full load before washing.

    ; Select the shortest possible washing programme.

    ; Cold water detergents reduce electricity consumption.


    ; Use pressure cookers when preparing foods that take a long time to cook. ; Match pots and pans to stove plates. Small pots on large plates waste electricity. ; Do not use pots with distorted bottoms.

    ; Switch off the plates or oven before food is fully cooked, allowing completion of cooking at a diminishing heat.

    ; Keep oven doors closed until food is cooked.

    Microwave Ovens

    ; When you defrost food, leave it in the fridge overnight. You will use less electricity than defrosting food in the microwave.

    ; Use the microwave to cook small to medium quantities of food. For larger portions of meat, it is better to use a conventional oven or pressure cooker.


    ; Don’t open the door unnecessarily and make sure the seal is intact

    ; Turn off an empty refrigerator when going on holiday.

    ; Let hot foods cool down before placing them in the refrigerator.

    ; Defrost fridges regularly. A build up of ice reduces operating efficiency and increases running costs.


    ; Freezers work harder to remove heat and have to use more power only 90% of a freezer’s

    capacity should be used for freezing.

    ; Defrost regularly.


    ; Do not buy larger and more powerful appliances than are actually required. ; Do not buy an electric appliance where a hand-operated one will suffice. ; Use the correct appliance for the job e.g. do not make toast on the stove or in the oven. ; Do not fill a kettle if only a small quantity of boiling water is required. It is sufficient to put in only

    enough water to cover the element.

    ; It is more economical to boil water in a kettle rather than in a pot on the stove. ; Always use an iron that is thermostatically controlled. You can avoid ironing clothes by removing clothing promptly from tumble dryer and folding them carefully.

    ; Operate swimming pool filter pumps for minimum periods.

    See the table below to assist you in managing your electricity usage. Please note that the figures are only guidelines as electrical ratings and usage change according to individual needs. The costs have been sourced from Eskom Demand Side Management 2006.

To calculate the monthly cost of each appliance, use the following formula:

    Electrical rating in kW x Hours per day x Days per month x Cost per kWh (residential rate)

The following calculation is based on the dishwasher example:

    1. The electrical rating in column 2 is given in watts. To convert to kilowatts (kW) divide the rating in

    watts by 1 000 e.g.

     2 700 W divided by 1 000 = 2,7 kW


2. Electricity usage (kWh) is obtained by multiplying the rating of the appliance (in kilowatts) by the

    number of hours it is used in the month e.g.

     2,7 kW x 2 hours x 25 days = 135,0 kWh

    3. Finally, the monthly cost to run an appliance is obtained by multiplying the electricity usage per

    month (kWh) by the cost of one unit of electricity (40.1c) e.g.

     135,0 kWh x 40.1c = R 54.13

    Household Electrical Consumption

    Electrical Hours Days kWh Monthly

    (Units) Kitchen rating in watts per per used cost

     (1000W=1kW) day month per month (40.1c/kWh) Dishwasher: Heater and motor 2700 2.00 25 135.0 R 54.13 Electric stove front large plate 2000 2.00 30 120.0 R 48.12 Electric stove front small plate 1500 1.00 15 22.5 R 9.02 Electric stove back large plate 1500 1.50 30 67.5 R 27.06 Electric stove back small plate 1000 1.00 25 25.0 R 10.02 Electric oven grill element 2200 0.50 15 16.5 R 6.62 Electric oven bake element 1900 0.50 20 19.00 R 7.62 Electric two plate stove (Hotplate) 2000 3.50 30 210.0 R 84.21 Freezer (chest) 230 6.50 30