Certain individuals have a poor habit of leaving lights on when exiting a room. Some even neglect to turn off lights before leaving the house. Is this a significant event? Determine the true energy consumption of lighting.
How much does leaving the lights on cost?
Light bulbs are not all made equal. Incandescent bulbs are the least efficient and most costly lighting technology still in use today. The Department of Energy breaks down power use and expenses by bulb, which is equivalent to a 60 watt (W) incandescent in terms of brightness:
- A 60W incandescent bulb consumes around 0.06 kilowatt-hours (kWh) of power every hour. This equates to 60 kWh of power consumed after 1,000 hours. This equates to $6.60 at $0.11 per kWh.
- 43W Halogen: Slightly more efficient than incandescent lights, halogens consume around 25% less energy to create the same amount of light as incandescent lights. One bulb costs around $4.73 to operate after 1,000 hours of use.
- 15W CFL: A compact fluorescent lamp is approximately 75% more efficient than an incandescent bulb and costs only $1.65 to operate for 1,000 hours.
- 12W LED: The most efficient of all lighting technologies, light-emitting diodes are up to 80% more efficient than incandescent bulbs. A single LED costs only $1.32 to run for 1,000 hours.
Lighting Costs Add Up
At first glance, the figures above may convince you that leaving your lights on is no great issue. However, when you consider how many lights you have in your house and how long you leave them on each day, the expenditures rapidly pile up.
The average house, according to Energy Star, contains 40 light bulbs. Lighting your home consumes around 20% of your power bill, costing the average homeowner $200 each year. Consider the amount of money you spend on different types of bulbs – and the amount you may save by turning them off when you leave.
- Incandescent: It’s unlikely that you’ve ever had every light in your house on at the same time. If you keep ten incandescent lights on for an hour per day when they are not required, this adds an additional $24 to your annual lighting expenditures.
- Halogen: If you keep ten halogen lights on for an hour per day when they are not required, you will incur an additional $17 in annual lighting costs.
- CFL: If you keep ten CFLs on for an hour per day when they are not required, you will incur an additional $6 in annual lighting costs.
If you keep ten LEDs on for an hour per day when they are not required, this adds an additional $5 to your annual lighting expenditures.
When to Turn Off Lights to Save Money
Are you wasting more power by continually turning off and on your lights? While a few bucks here and there may not seem like much, knowing when to switch off your lights according to the DOE can optimize your savings:
- Incandescent and halogen lights: Because these are the least efficient types of bulbs, you should switch them off when not in use to optimize your savings.
- CFL: The economics of switching off CFLs are a little more challenging. As a general guideline, switch them off if you will be gone for less than 15 minutes. Contrary to common opinion, this is not because CFLs use a great deal of energy at startup. Indeed, the “inrush” of current is only approximately five seconds long. However, the cost reductions come from extending the life of the bulb. After all, CFLs degrade more quickly when turned on and off often.
- LED: The on-and-off operation of LEDs has no effect on their working life. This implies that you should always switch off LEDs while leaving a room.