Light Globe Conversion Table Watts are the measure of power, lumens are the intensity of light. Incandescent bulbs Compact fluorescent Halogen lamp Light output in lumens (lm) light light (CFL) intensity 25 watts 5-7 watts 18 watts 220 lm 40 watts 7-8 watts 28 watts 420 lm 60 watts 11-12 watts 42 watts 720 lm 100 watts 13-18 watts 52 watts 930 lm Halogen light globes are also more efficient than incandescent globes but they get very hot and are a concern with ceiling insulation. Halogen light globes are often more numerous, so instead of having one or two incandescent or CFL globes, 8-10 are installed, which ‘down lights’ reduces the benefit of the reduced power usage. Light emitting diodes (LEDs) are the new kid on the block in lighting. With a life span of 30,000 hours compared to incandescent globes (1000hrs) and compact fluorescent lamps (8000hrs) they have a lot to live up to. A 13W LED has the equivalent power of a 100W incandescent globe and around 800 lumens! That is a big light source, for little power and long life. Light energy audit Aim: To make an estimation of the costs of lighting in your home for a year. Method Undertake an audit of all the lights in your house and fill in the table below. Use the in ‘difference energy’ column to compare the light sources used in your house with one of the others discussed Power Power Average Energy Cost Cost per Difference usage running used per per year ($) in energy usage time per week week usage/ cost (kWh) (Costs (Watts) week (kWh) ($) per kWh $ (hours) (kWh x (0.27x week x hours) kWh) 52) E.g. 70 70/1000 21 0.07 x 21 = 0.39X52 Halogen 1.47 0.07 $20.28 Bulb 0.39 (39 cents)
Light Globe Conversion Table Watts are the measure of power, lumens are the intensity of light. Incandescent bulbs Compact fluorescent light (CFL) Halogen lamp Light output in lumens (lm) light intensity 25 watts 5-7 watts 18 watts 220 lm 40 watts 7-8 watts 28 watts 420 lm 60 watts 11-12 watts 42 watts 720 lm 100 watts 13-18 watts 52 watts 930 lm Halogen light globes are also more efficient than incandescent globes but they get very hot and are a concern with ceiling insulation. Halogen light globes are often more numerous, so instead of having one or two incandescent or CFL globes, 8-10 ‘down lights’ are installed, which reduces the benefit of the reduced power usage. Light emitting diodes (LEDs) are the new kid on the block in lighting. With a life span of 30,000 hours compared to incandescent globes (1000hrs) and compact fluorescent lamps (8000hrs) they have a lot to live up to. A 13W LED has the equivalent power of a 100W incandescent globe and around 800 lumens! That is a big light source, for little power and long life. Light energy audit Aim: To make an estimation of the costs of lighting in your home for a year. Method Undertake an audit of all the lights in your house and fill in the table below. Use the ‘difference in energy’ column to compare the light sources used in your house with one of the others discussed Power usage (Watts) Power usage (kWh) Average running time per week (hours) Energy used per week (kWh) (kWh x hours) Cost per week ($) (0.27x kWh) Cost per year ($) (Costs per week x 52) Difference in energy usage/ cost kWh $ E.g. Halogen Bulb 70 70/1000 0.07 21 0.07 x 21 = 1.47 0.39 (39 cents) 0.39X52 $20.28