Key Aspects About Electricity Consumption

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Different consumers, different requirements

Consumers have requirements that rarely fit exactly to predictions and even to previous patterns, as there is always some variability due to activity, external or internal factors. This is why electricity consumption control is, most of the time, a best-effort attempt. No two business or home consumers are alike but there are some good practices that can be followed to determine what could be done to control consumption.

Activity specificity

It is essential to know and monitor how frequently large appliances are being used. Electric ovens, cooking machines, boilers, space heaters, have the highest energy consumption. They may be required to work at different temperatures and for different amounts of time. Keep in mind that a higher temperature and a long operation means a high consumption.

For a business centered on selling food, the whole food production chain may have to be studied to determine what could be done quicker or with less heating. Sometimes, there may not be easy solutions that would not compromise quality, variation or appeal.

In the case of office activities, especially for mid-sized areas, computers, servers and auxiliary equipment have a very large impact on electricity consumption. Distance working and non-standard schedules requires all computers to be turned on, 24 hours a day, 7 days a week, and this creates a constant important electricity demand.

Making sure that employees willingly turn off their computers or there is a policy that is imposed by the administration may have a major effect. It has to be determined if employee flexibility is required or is an advantage.

At other times, this may simply not be an option as is the case for some support services or solution providers. Having a single computer that may service multiple users can also be a working solution in certain situations. It is more costly to maintain a multiple concurrent user access system, but it may be cheaper than to have separate systems.

In the case of workshops or other activities, there may be specific energy requirements that are highly dependent on client demand and have very few optimization possibility without resorting to replacing current equipment with more modern and energy efficient appliances. Such an approach may or may not be feasible.

Most common electricity consuming devices

Computers, TVs, laptops, printers, multifunction devices

Using computers, printers and other data processing equipment is unavoidable in our modern life. However, most devices require a certain amount of electricity to work, although size and backside labels can give relevant consumption details.

Keep in mind that multiple devices that are powered on at roughly the same time may have a certain impact on electricity consumption. Laptops always consume less than desktops so for activities that are not particularly processing demanding, they may be better suited for daytime work.

Device Typical power rating Sample rating Daily use Monthly consumption
Desktop computer, medium use and load 50-400 W 100 W 8 hours 24 kW/h
Laptop computer, medium use and load 10-90 W 30 W 8 hours 7.2 kW/h
120cm LCD TV 10-130 W 60 W 8 hours 19 kW/h
Laser printer/copier multifunction device 700-1500 W 1000 W 0.5 hour 15 kW/h
Inkjet multifunction device 10-40 W 25 W 0.5 hour 0.3 kW/h

Printers and multifunction devices should be given special attention. While inkjet printers are usually low powered devices, with a power rating that is less than 50 Watts, some larger copiers, printers and multifunction devices, particularly laser ones, can have very large instantaneous power loads and this will be translated into high consumption for high volume activities.

However, high printing volume devices are rarely anything else but the laser type. Keep in mind that the ink-paper fusing process is the main consumption culprit. There are also other printers such as thermal transfer or 3D ones that also have quite an important contribution to electricity consumption.

TVs have been, for quite a long time, devices that do not consume much electricity, most being under the 100 Watts power range. However, when used all day long and in numbers, consumption figures add up and energy efficiency may make more modern or advanced devices particularly attractive.

Washing machines, clothes driers

Taking care of clothes is a necessity. Unfortunately, it is not only a time-consuming activity but it also has a large impact on electricity consumption. Considering a washing schedule can influence energy requirements.

A single washing day can be more or less convenient depending on actual working and leisure activity conditions. Sometimes it may be necessary to have a washing activity two or three times a week or even daily, in case of a business in the hospitality industry.

This aspect has to be considered carefully, keeping in mind that washing only certain clothing items, as they are used, require more energy and water than washing a bunch of clothes. In other cases, communal washing may not be the best choice for sanitary, privacy or scheduling reasons.

Device Typical power rating Sample rating Daily use Monthly consumption
Common washing machine 1200-2000 W 1500 W (only during water heating) 1 hour 11.25 kW/h
Older washing machine 1200-2000 W 1800 W (only during water heating) 1.3 hours 17.55 kW/h

While clothes driers and washing machines that have integrated driers are highly convenient, they do have an impact on energy consumption. While airing and drying clothes outside is preferable, colder or more humid environments make such an option frequently inconvenient.

Moreover, drying clothes outside can increase the chance of them attracting dust or being touched by birds, which raises other issues. More energy efficient clothes driers use heat pump systems that reduce energy load.

The question of a clothes drier or a washing machine with combined drier depends on washing load requirements per week, convenience and available space. A separate clothes drier can free the washing machine for another batch of clothes.

In situations were a clothes drier is too inconvenient, expensive or takes too much space, stand-alone dehumidifiers or air-conditioning systems can improve clothes drying performance indoors.

Irons, hair-driers

Ironing require quite extensive energy inputs and is a major contributor to consumption, particularly if done regularly. Traditional ironing systems are less efficient than vertical ones for small fabric straightening purposes.

Ironing also releases water vapours as well as heat, increasing local humidity and creating an environment that is less pleasant to work in. Unfortunately, there are fabrics that need to be cared for with ironing.

Device Typical power rating Sample rating Daily use Monthly consumption
Standard Iron 800-2100 W 2100 W 0.1 hours (6 minutes) 6.3 kW/h
Vertical Iron 1400-1600 W 1600 W 0.1 hours (6 minutes) 4.8 kW/h

The best solution is to find fabrics and clothing products that trap the least amount of water and require the least amount of special care, such as ironing, to look right. Unfortunately, as there are no international standards and guidelines for efficiency in this area, a lot of personal experimentation has to be carried out.

Hair driers are a necessary hair care device that may have quite an impact on electricity consumption, particularly for businesses such as hairdressers or homes with a large number of occupants. For the moment, the best improvement potential is to have many heat settings (3 or more) on a hairdryer, adapting distance and heat as it fits.

Device Typical power rating Sample rating Daily use Monthly consumption
Travel (compact) hairdryer, short hair 1100-1200 W 600 W (low setting) 0.25 hours (15 minutes) 4.5 kW/h
Travel (compact) hairdryer, long hair 1100-1200 W 1200 W (high setting) 0.45 hours (27 minutes) 8.1 kW/h
Standard hairdryer, short hair 2000-2200 W 1000 W (low setting) 0.15 hours (9 minutes) 4.5 kW/h
Standard hairdryer, long hair 2000-2200 W 1000 W (low setting) 0.25 hours (15 minutes) 7.5 kW/h

Having efficient, focused, airflow that is very close to the hair yet not hot enough may help in using a more economical power rating. However, there are still cases where airflow and distance to the hair are more important for certain care activities. Longer hair requires considerably more drying time, typically twice or more as long as for short hair.

Cafetieres, kettles, grills, other food preparation devices

Appliances that heat water or food can have quite an important contribution to overall consumption. In many cases, they are much more convenient to use and more efficient and than, for instance, simple teapots used on an electric cooking machine.

Purpose built devices can be optimized and this is certainly the case. However, as in most cases, it stands to reason that they have to be determined as essential to be used in a certain manner.

In the case of an office, it all boils down to convenience and a pleasant working climate. If few employees use such devices on a constant basis, there is no major concern about consumption, although more efficient devices would help in limiting consumption.

However, if there is a strong demand for cafes or teas, there may need to be an assessment about how to better handle the situation.

Device Typical power rating Sample rating Daily use Monthly consumption
Common kettle 2000-3100 W 2000 W 0.3 hour 18 kW/h
Common cafetiere 600-1000 W 600 W 2 hours (if left running) 36 kW/h
Common grill 1000-2100 W 1500 W 0.5 hours 27 kW/h
Common toaster 600-1000 W 800 W 0.25 hours 6 kW/h
Common water dispenser 120 W (cooling)-430 W (heating) 400 W 2 hours 18 kW/h

For businesses that have food preparation activities, the issue is much more complex. Serving quickly clients is mandatory and appliances that can ensure this result are highly important.

Replacing or giving up on a specific appliance altogether is a decision that takes into account many aspects and has to be thoroughly analyzed. Space constraints and employee capabilities also play a part in this case.

Mixing, cutting and other specialized preparation appliances also have an important impact on consumption, particularly if they are frequently used, as in business activities, and more energy efficient or better performance ones can have major benefits.

It is important to keep in mind that specialized electrical devices are much more convenient to reconfigure and optimize than general ones such as a cooking machine, so workflow optimizations should be centered on how to better handle specific activity demands.

Refrigerators and freezers

Refrigeration covers not only the obvious purpose of storing food and food related products that can degrade but also water chilling systems. Environment temperatures have the largest influence on a refrigeration equipment consumption both during normal operation and particularly when drafts are formed as the appliance is open for loading or unloading.

Another important aspect pertains how frequent the device is being loaded or unloaded as well as accessibility of certain frequently used products. A highly loaded refrigerator or freezer can use more energy to cool products stored inside and requires more time to access certain items. A lower inside temperature preset also requires more power.

Device Typical power rating Sample rating Daily use Monthly consumption
Common 300 Liter refrigerator/freezer combo, 25 Celsius degree ambient 100-300 W 200 W 6 hours (combined running time) 36 kW/h
Common 300 Liter refrigerator/freezer combo, 30 Celsius degree ambient 100-300 W 200 W 12 hours (combined running time) 72 kW/h
Older 300 Liter refrigerator/freezer combo, 25 Celsius degree ambient 200-400 W 300 W 6 hours (combined running time) 54 kW/h

It is also important to note that high refrigeration volumes have to be managed carefully to avoid items that are forgotten, going past their intended consumption date. Water chillers and dispensers are convenient devices that have to be properly sized to be efficient but they are much more advantageous to use than refilling, storing and retrieving water from a standard refrigerator.

This means that refrigerator volume and positioning are highly important aspects that have to be considered along typical energy efficiency. Overall, chest freezer can have the largest efficiency for storage as well as energy use while shop or glass door refrigerators have the poorest one.

Space cooling, heating, ventilation equipment

Space heating and cooling may require considerable amounts of electricity. It may be helpful to establish specific temperature ranges at which appliances are turned on an off to maintain comfort. This will have a very large impact, particularly in summer. Permanent monitoring of temperature and humidity is essential to asess how to maintain it in an acceptable range.

Water heating that depends on tap water also evolves thought a year. Since tap water is cooler in winter, boilers are requiring more electricity to heat the water to the same temperature than during summer. Also, in summer, hotter water may be less desirable to work with, so a lower temperature can be sufficient.

Device Typical power rating Sample rating Daily use Monthly consumption
Common 12000 BTU air conditioning unit 1200-1500 W 1200 W 8 hours (combined running time)* 288 kW/h
Common large circulation fan 40-200 W 100 W 8 hours 24 kW/h
 Note: *the case scenario considers a 25 square meter indoor area, 35 Celsius degree exterior temperature, 25 Celsius degree interior temperature desired

All these situations have to be carefully studied. It is not as effective to just use the "eco" function for certain devices, since it will just provide a lower service, in this case water temperature and electricity consumption, that may not be satisfactory for most purposes.

Ventilation generally has the small impact on consumption as moving the air requires quite a low amount of electricity and fan systems are highly efficient. However, ventilation does pose certain challenges. A lack of airtightness in the building envelope may increase air ingress in spaces where odours and humidity should not reach.

Just as well, forced ventilation may not be effective in a building envelope that is almost airtight as there is not enough airflow that can be maintained. This means that kitchens and bathrooms should be particularly airtight to other spaces while ventilated well enough without affecting other areas, a quite difficult balance.

Cleaning appliances

Although space cleaning appliances are rarely considered a major factor in energy consumption and they may not be an obvious contributor, they should not be omitted. Vacuum cleaners have a certain electrical input that is indicated on labels.

Better performing products are generally more expensive and durable than economy ones. It matters a lot when operating older devices, manufactured more than 7 years ago, as they can be performing well but require more electrical energy due to having a less efficient electrical motor.

Device Typical power rating Sample rating Daily use Monthly consumption
Standard vacuum cleaner 500-600 W 600 W 0.25 hours (15 minutes) 4.5 kW/h
Older vacuum cleaner 1000-2000 W 1200 W 0.25 hours (15 minutes) 9 kW/h

Pressure washers are much more effective for cleaning ceramic tiled floors, concrete and asphalt, being highly effective both on the indoors and outdoors activities. They can also save a lot of time and also a lot of money, reducing the need for expensive and toxic cleaning products. Pressure washers also reduce water use making more savings readily apparent.

Lighting equipment

Ensuring a properly lit indoor or outdoor used to require significant energy consumption. This may still be the case for very old installations but retrofits or modern systems are rarely high consumers.

A higher surface area that has to be covered and more intense light leads to higher electricity demand and energy consumption.

Device Typical power rating Sample rating Daily use Monthly consumption
Common LED lamp 5-20 W 15 W 6 hours 2.7 kW/h
Common LED lamps 5-20 W 1600 W 10 hours 4.5 kW/h
Old fluorescent lamp 18-40 W 40 W 10 hours 12 kW/h
Old outdoor lamp 100-250 W 100 W 10 hours 30 kW/h

Lighting systems tend to not require high investments for modernization purposes but some specialized systems may still command a high price, so it is advisable to determine the current situation.