Hello there! I'm an expert in energy efficiency and home economics. I'm here to provide you with a detailed answer to your question regarding the cost of leaving a light on for an hour.

Firstly, it's essential to understand that the cost of electricity varies significantly depending on your location and the time of day. Electricity rates can be influenced by factors such as the source of power, transmission costs, and local taxes. However, for the sake of this explanation, let's assume an average cost of electricity, which is a common approach to give a general idea.

The cost of leaving a light on for an hour can be calculated by multiplying the power consumption of the light bulb by the cost per kilowatt-hour (kWh). The power consumption of a light bulb is measured in watts (W), and the cost per kWh is typically provided by your energy provider.

Let's break down the costs for different types of light bulbs:

Incandescent Bulbs: These are the traditional light bulbs that have been used for many years. They are relatively inexpensive to purchase but consume more energy and have a shorter lifespan. An incandescent bulb typically uses around 60 watts of power. If we take the average cost of electricity to be 0.12 USD per kWh (which is a common rate in many regions), the cost for an hour of use would be:

\[ \text{Cost} = \text{Power Consumption (W)} \times \text{Cost per kWh} \times \text{Time (hours)} \]
\[ \text{Cost} = 60 \text{ W} \times 0.12 \text{ USD/kWh} \times 1 \text{ hour} = 0.0072 \text{ USD} \]
\[ \text{Cost} = 7.2 \text{ cents} \]

LED Bulbs: LED (Light Emitting Diode) bulbs are more energy-efficient and have a longer lifespan compared to incandescent bulbs. They consume significantly less power, typically around 9 watts for a bulb that provides the same amount of light as a 60-watt incandescent bulb. Using the same cost of electricity:

\[ \text{Cost} = 9 \text{ W} \times 0.12 \text{ USD/kWh} \times 1 \text{ hour} = 0.00108 \text{ USD} \]
\[ \text{Cost} = 1.08 \text{ cents} \]

CFL Bulbs: Compact Fluorescent Lights (CFLs) are another energy-saving option. They use less power than incandescent bulbs but more than LEDs. A CFL might use around 15 watts for the same light output. The cost calculation would be:

\[ \text{Cost} = 15 \text{ W} \times 0.12 \text{ USD/kWh} \times 1 \text{ hour} = 0.002 \text{ USD} \]
\[ \text{Cost} = 2 \text{ cents} \]

Now, let's address the information you provided. It states that a normal incandescent bulb costs about 0.75 cents per hour, and LEDs or CFLs cost only one-sixth of that. This information seems to be outdated or based on different electricity rates. Based on the calculations above, an incandescent bulb would cost approximately 7.2 cents per hour at the assumed electricity rate, and LEDs or CFLs would be significantly less.

It's also important to note that leaving lights on for extended periods, such as overnight or while you're at work, can add up to a considerable cost over time. For instance, leaving an incandescent bulb on for 8 hours would cost:

\[ \text{Cost} = 60 \text{ W} \times 0.12 \text{ USD/kWh} \times 8 \text{ hours} = 0.0576 \text{ USD} \]
\[ \text{Cost} = 57.6 \text{ cents} \]

For LEDs, the cost would be:

\[ \text{Cost} = 9 \text{ W} \times 0.12 \text{ USD/kWh} \times 8 \text{ hours} = 0.00864 \text{ USD} \]
\[ \text{Cost} = 8.64 \text{ cents} \]

And for CFLs:

\[ \text{Cost} = 15 \text{ W} \times 0.12 \text{ USD/kWh} \times 8 \text{ hours} = 0.0144 \text{ USD} \]
\[ \text{Cost} = 14.4 \text{ cents} \]

In conclusion, the cost of leaving a light on for an hour is relatively low, but it's a good practice to turn off lights when they're not needed to save energy and reduce your electricity bill. Opting for energy-efficient bulbs like LEDs can significantly lower your energy consumption and cost over time.

read more >>

A --normal-- incandescent bulb costs about 0.75cents per hour, and LEDs or CFLs cost only one-sixth of that -C so leaving the lights on (either overnight or while you're at work for the day, say both are about 8 hours) costs you roughly 6 cents for a normal light and a bit over 1 cent for modern bulbs.read more >>