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by Dr. Lareef Zubair , International Research Institute for Climate Prediction, USA

Some years back, the electricity bill at our home in Akurana was a thousand rupees. My parents were alarmed. To investigate, they shut off all the appliances and turned on one by one and watched how fast the indicator disc on the electricity meter revolved. To their surprise, a water heater and a television that were left on indiscriminately speeded the meter rapidly.

They chose to use these devices sparingly. They substituted fluorescent lamps for the incandescent bulbs that were used most. Everyone was careful to switch off lights when not needed. We removed the scales that had deposited on the heating coils of the water heater. These adjustments reduced our electricity bill to Rs. 300.

Motivations

What my parents carried out was a crude energy audit. They identified the devices which consumed electricity excessively and chose to be careful in using them. Conserving energy thus does not result in loss off amenities. Really, one uses appliances as they should be conscious of the operational cost. One maintains them and they last longer. Hazards are reduced. One also thinks of energy-efficient alternatives.

In the case of my parents, the cost of electricity prompted them to conserve, Now there is a national electricity shortfall; hospitals and the weak are without electricity. So there is an ethical imperative to conserve. Each time we use electricity, we contribute to environmental degradation. To produce hydro-electricity, dams and tunnels are built on rivers harming the ground water, the aquatic life and the plant life on the banks. Silt and unnatural chemicals collect in the reservoir. Even if you use a generator, you still consume scarce fossil fuel and vent petroleum fumes to the air we all breathe and make a racket.

Our home is not typical in that it has electricity and pipe-borne water. Such homes, however, take up a third of the electricity that is generated and this article will focus on means of conserving energy for similar homes that accounts for 30% of the total electricity consumption in Sri Lanka.

"Auditing" electricity use

To identify where you use energy most, conduct an "energy audit". You can do the meter watching which my parents did. You will get a better understanding by quantitatively breaking down your energy consumption device. To do this multiply the power rating of your appliances in kilowatts (or a thousand watts) with its approximate monthly use in hours. If the equipment does not have a power rating or is in dilapidated state then you can estimate the power rating by turning on that appliance and nothing else and recording the change in the reading of your electricity meter for a fixed duration.

Most meters can show a consumption of a tenth of a kilowatt-hour unit. For some equipment, you may have to wait too long for the meter to change by a tenth of a unit. For such equipment, estimate the consumption by counting the number of revolutions of the disk for a fixed duration. Then divide this number by the number of times that the disk rotates for a kilowatt-hour which is marked on the face of your meter and is around 800 revolutions per kilowatt-hour. Again divide this new number by the time elapse in hours to estimate the power ratings in kilowatt's. Then estimate your monthly consumption by multiplying this power rating by the monthly usage of the device in hours.

Current price of Electricity per unit

Minimum Rs. 3.00

Average Rs. 6.00

Maximum Rs. 10.13

(Inclusive all taxes)

Going through this exercise will give you a breakdown of electricity consumption device by device. Check wether your total tallies with your electricity bills. If it does not, check for errors. Focus your efforts on the devices that use the most energy. Energy is consumed for ventilation, cooling, illumination, cooking, recreation and supplying water.

Nature can ventilate your building for free by means of wind and thermal air currants. For the wind to push air through, there must be adequate window openings and ventilation holes. Any obstruction diminishes ventilation. Netting your window with a fine mesh cuts down on airflow. If you must put a netting to keep out mosquitoes use the largest mesh possible. If the mosquitoes bother only during the evening, arrange the netting so that you can detach it or roll it up during the morning and afternoon. Clean the netting regularly. When you partition your rooms, be attentive to how you affect the ventilation.

Another means of natural circulation is thermal air currants. Indeed ventilation towers have been used for many centuries effectively in the deserts of Arabia. Hot air rises and draws in its wake, cool air from outside. In some houses with gabled or slanted roofs is that the ridge or the top of the roof is sealed off either with cement and tiles, asbestos ridge sheets or walls. Hot air gets trapped under the roof and radiates heat back to the house. All you have to do alleviate this "oven effect" is to provide holes at the top of your roof through which the air can get out.

Even when the weather outside is pleasant, many homes are hot and humid. Improved ventilation will help cool the indoors. The heating of your interior depends on your roof and walls. Cadjan roofs are better than tiles; tiles are better than asbestos; and asbestos better than concrete. Shade trees or creepers overhanging the roof can cool interiors drastically. Thin metal foils can be laid under the roof to reflect the heat back.

Dark curtains can slow the transmission of heat. If your home is hot at night put screens outside your windows. Lighter paint on your outside wall will reflect the heat. If these measures are inadequate, use fans. Ensure it moves hot air out of the room. Fans use much less energy than air-conditioners. If you must use an air-conditioner, then condition only the space that needs it. See that air does not leak out of the room; set your air-conditioner to the warmest comfortable temperature. Keep it off when not required.

Keep the radiator of the air conditioner clean.

If and when your home is cold, you can counteract heat losses. Ventilate only so that the air does not become stale. Trap the air that is heated during the daytime. Check whether warm air leaks from your windows and doors. If you must use a space heater, keep it well tuned and cleaned up.

If it has a furnace check the efficiency of its combustion. Excessive smoke is due to poor combustion. Soot deposits can increase your energy consumption. I am not aware of solar space heaters in Sri Lanka but hope an enthusiast will develop one.

Solar water heaters that can warm up the water are commercially available. Unfortunately these heaters are expensive at around Rs. 50,000. It is possible to fabricate a domestic solar heater using local materials, which can be sold at Rs. 20,000.

Illumination and lighting

Sunlight is abundant outside. But, often, we arrange our interiors so that they are dark. Many buildings have not exploited sunlight which is natural, free, pleasant and needs no conversion. In several instances, partitioning has cut off natural lighting. Apart from ensuring that buildings are sensibly designed, simple alterations or retrofitting of buildings may be worthwhile.

Choose your glazing with care. Tinted glasses halve the entry of light. It is best to have clear glass and draw curtains over them to cut down glare. Even frosted glass cuts down the entry of light.

Roof lighting is aesthetic and more effective than lighting from the side. Glass blocks or panes can be built into concrete; glass tiles can be laid on a tiled roof; and translucent sheets can be incorporated into asbestos and galvanized iron roofs.

One can make the most of the available lighting by choosing reflective interior finishes so that light gets reflected within the room many times before being absorbed. The walls, ceiling and floor should be of lighter shades.

Electric lighting should be directed to places where it is needed. One can conserve by using a low power lamp directed to a table, where light is needed, rather than illuminate an entire room with a high-powered lamp.

One can save energy by switching over from incandescent to fluorescent lamps. The compact fluorescent lamps and the thin fluorescent that are available now are more efficient than the old tube-lights. Compact fluorescent use approximately a fifth of the power of an incandescent bulb to provide the same illumination. In the past, fluorescent had a commercial appearance, were expensive and unwieldy. Now compact fluorescent lamps has changed all that.

These emit a mellow light; fit into ordinary sockets and costs a subsidised price of Rs. 600 upwards. It is more expensive than an ordinary bulb but it lasts ten times longer. Still the return in investing in a fluorescent is attractive only when you get charged above Rs. 4 per unit, if these lamps are lit at least for two hours each day and if you are not likely to lose these bulbs by mishandling or theft.

Conserving water

Conserving tap water conserves energy. There is a substantial energy cost to purifying and to pumping water that is not reflected in our water bills.

Householders pay a sliding scale that starts at Rs. 1.20 for a unit whereas the cost to the Water supply and Drainage Board is ten times as much depending on the area. Even this cost does not factor in the environmental damage of removing water from aquifers or rivers. Water in aquifers that accumulates over centuries is depleted over decades. Taking water out of the rivers is to impair the river ecology. Dams cuts off migratory routes for fish, despoils groundwater in the region and leads to the accumulation of silt and chemicals. Even when we send out our chemically treated water, we harm microorganisms.

While water is dear, our use of it is particularly wasteful. Keeping a tap open while brushing your teeth may run down several gallons. Shaving and washing clothes and dishes with an open tap and hosing down cars wastes tens of gallons.

Cistern flushes send down four gallons with each use. You can save on shaving and washing by collecting the water you need before hand. You can save on flushing by inserting a closed plastic bottle weighted with sand in your cistern. Experiment with bottles of different sizes to determine the volume of each flush. Another ignored major factor is water leaks. We can all attend to prevent leaks.

For many houses there is an energy-free, environment-friendly means of supplementing the water supply. That is rainwater. It is pure, it can be collected at any height; it is free of chlorine and it is available from your roof. You will get it no matter whoever on earth is on strike. It makes sense to collect the rainwater from your gutters in a tank and use it for bathing, gardening and washing. Moreover you reduce the outflow in your drains during rains.

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