How to calculate the energy consumption of light bulbs at home?

Any electrical device, be it a television, an iron or a light bulb, uses a certain amount of electricity. Although this depends on various factors, the element that has the greatest impact on a given device’s energy consumption is performance. The higher the power of a particular device or lamp, the higher the power consumption and the higher the costs associated with its use.

With some simple data, including watts, you can calculate how each appliance and bulb will affect your utility bill at the end of the month. The calculations are not difficult and can be done by anyone. Therefore, it is crucial for your home and the planet to choose the right lamps for your home, such as the most energy-efficient lamps from

Calculate energy consumption

To calculate the energy consumption, three variables are needed: the power, the number of hours and the days of use. The calculation is very simple: you just need to multiply the known power by the number of hours the bulb is on and the number of days it has been used.

For example, imagine that you want to know the consumption of a 60-watt light bulb that is on for 5 hours a day for 30 days. In this case, the calculation of energy consumption is as follows:

  • Energy consumption = 60 W x 30 x 5 hours
  • Energy consumption = 9000Wh

If you check an electricity bill, you’ll find that utilities make their calculations in kilowatt-hours (kWh) rather than watt-hours (Wh). To convert between the two units, all you need to know is that a kilowatt is equal to 1000 watts. This means that if your electricity bill shows an output of 200 kWh, you have actually used 200,000 watt-hours.

Therefore, you must remember that it is necessary to convert to kWh. So in the example, divide the result by 1000 to get the value of 9 kWh. In the end, you know that each bulb with these production and usage characteristics used 9 kWh during the month.

This calculation even works for all electronic devices, not just light bulbs. If you add up the consumption of all units, you get the result in kWh, which is indicated on the electricity bill.

Calculate the cost

Now that you know how to calculate usage, how can you figure out the monthly cost? With another simple equation that doesn’t require much. All you have to do is check your electricity bill to see how much you pay per kWh. With this data in hand, multiply it by the calculated consumption to find the monthly cost of each light bulb in your home.

To make it easier, imagine that the electricity company charges you €0.105 per kWh consumed. In the previous calculation, you concluded that each bulb consumes 9 kWh per month.

The monthly consumption costs for each lamp are therefore as follows:

  • Price = 9 x 0.105
  • Usage costs = €0.945

This means that each bulb costs just under €1.00 on your electricity bill. One catch not to fall for, however, is that your house probably doesn’t just have a single light bulb.

All units together contribute to this cost. If the conditions are the same for all lamps, the consumption will be the same for all. Imagine a house with about 5 rooms. Due to the lighting concept, about 10 such lamps are used 5 hours a day every day of the month.

The cost calculation is as follows:

  • Cost using all lamps = 10 x 0.945
  • Cost of using all lamps = €9.45

A message: The values ​​are unrealistic and only serve to illustrate the calculation.

LED bulbs vs. Fluorescent tubes: Which one is better?

Have you ever had doubts when buying lamps for your home? For which is best? Which ones save more energy? What is the best cost-benefit ratio?

There are many questions on this subject, especially after the extinction of the old light bulbs, which have given way to fluorescent tubes. But now there is a new type that promises even greater benefits: LED bulbs.

Fluorescent bulbs

Temperature: The main advantage of fluorescent tubes is that the energy they use does not emit heat, that is, they do not get hot when used like the old incandescent lamps. Therefore, almost everything that is consumed ends up being converted into light.

Savings: Fluorescent tubes produce around 80 lumens (lm) for every watt (W) consumed and therefore use much less energy. Therefore, you can save 80% of the bill at the end of the month.

Lumen is nothing more than the luminous flux, i.e. the potential for light emission. The value of the lumens produced for each watt consumed (lm/W) is the best way to measure whether the lamp you have chosen is really a good one.

Useful life: The lifetime of a fluorescent lamp is much longer than that of an incandescent lamp. They can last up to six times as long, a total of 8,000 hours, at a low price. They also use less energy when used continuously, meaning that the longer they are on, the less energy is used to produce the same lighting. They also don’t burn out easily when turned on and off.

LED bulbs

Temperature: LED lamps have a very low heat output, even lower than fluorescent lamps. They also do not emit infrared and ultraviolet rays, which is less harmful to eye health. As they do not damage the pieces or the plants, they can also be installed in museums and in areas with vegetation.

Maintenance: Roughly speaking, one LED bulb corresponds to 8 compact fluorescent tubes and almost 50 incandescent bulbs. This means that the LED version requires minimal maintenance costs, which is extremely positive as replacements are rarely required. Therefore, its main application area and the place where it is currently used most often is in hard-to-reach places, such as bridges and other tall public buildings.

Useful life: LED lamps have a long life. Their lifetime can vary from 25 to 50,000 hours. If left continuously, 8 hours a day, it can be used for up to 17 years. It all depends on the product, and there is a wide selection of models on the market.

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