Minimising your Lighting Costs
Higher wattage bulbs tend to be more efficient than lower wattage ones. One reason for this is the fact that thicker filaments can be operated at a higher temperature, which is better for radiating visible light.Another reason is that since higher wattage bulbs would lead you to use fewer bulbs, you buy fewer bulbs and the cost of bulbs becomes less important. To optimize cost effectiveness in this case of higher wattage light bulbs, the filaments are designed to run even hotter to improve energy efficiency to reduce your electricity costs.Smaller bulbs use less electricity apiece, making the cost of the bulb more important. This is why lower wattage bulbs are often designed to last 1500 to a few thousand hours instead of 750 to 1000 hours. Designing the bulbs to last longer reduces their light output and energy efficiency.To minimize your cost of both electricity and bulbs, you should use as few bulbs as possible, using higher wattage bulbs. To get the same amount of light with lower wattage bulbs, you need both more electricity and more bulbs.An even better way to reduce your lighting costs is to use fluorescent, compact fluorescent, or HID (mercury, metal halide, or sodium) lamps since these are 3 to 5 times as efficient as incandescent lamps.
How much can you save?
Obviously the lower the wattage of the lamp you choose, the lower your electricity bill will be, but please don't expect to replace a 50w halogen lamp with a 3w LED - you can physically do it but the light output will be nowhere near the same. You expect to save around 70% on running costs and as both LED and CFL lamps last much longer than Halogen lamps, the initial extra cost will pay back several times over the life of the lamp. You should also consider the convenience factor of not having to spend time changing lamps.
Low Voltage Lighting - Is it More Efficient?
It is a common assumption that low-voltage lighting (12v) draws less power than 'mains' 240v lighting. However, generally speaking, this is NOT the case. The amount electrical energy used per second is measured in Watts (w). The rated wattage of a product determines the how much it will cost to run. If a lamp is rated at 4w, it will consume that amount whether it is 'normal' or low voltage. This can be seen in the following formula:Wattage (W) = Voltage (V) x Current (A)To achieve a set wattage, the current in a low voltage system must be higher than that of a 240v system. In a low voltage system, the required transformers will also drain a small amount of power. Therefore, energy savings over normal supply voltage cannot be expected from a low voltage system.
