Save Watts


In the domestic sector the various types of lamps have been changing with the development of new technologies and energy efficiency needs. There are 5 different types of lamps: compact and tubular fluorescent lamps, LEDs, halogen lamps and incandescent lamps.

Because they are bulbs with excessive consumption, the incandescent lamps are no longer sold since 2012, after several years in discontinuity. For the same reason, low-efficiency halogen lamps began to be discontinued in September 2016, with an adaptation period until September 2018 where they were definitively excluded from the market [1].

The constant need to find lamps with a less exaggerated consumption led to the appearance of fluorescent lamps and LEDs. The latter are more efficient and therefore allow us to save more energy for the same use of lighting.

In the case of CFL, due to the maturity of the technology, the forecast is that it does not change significantly over the years. For LEDs the prediction is that they achieve luminous efficacies of 150-180 lm / W by 2020 [2], which allows much higher energy efficiency values ​​compared to other technologies.

[1] - Comissão Europeia -
[2] - Departament of Energy U.S Report - Solid-State Lighting R&D Plan

Energy Label - The energy label is a general reference on lamp efficiency. It can vary from E to A ++, the latter being considered more efficient. There are few models found today with a rating below B. The best models of LED bulbs reach the A ++ rating. In the case of CFL lamp models the maximum rating is A [1]. Still in this energy label, it is common to see the weighted energy consumption value, in kWh per 1000 hours, as a complement of information to the efficiency of the lamp in question. In the case of an A ++ LED lamp and a CFL A lamp, the kWh value per 1000 hours will be lower for the LED lamp. Due to the growing concern about energy efficiency, the trend is for more and more handsets to have ratings like A +, A ++ and A +++. This can create some confusion on the part of the consumers and, therefore, the decision was taken to phase out these classes over the next few years. The new system will return to the classification from A to G (without classes A +, A ++ and A +++), with a transition period in which the two systems will operate in parallel [2].

Lifetime - LEDs continue to be the front runner, as they can last up to 25000 hours. In turn CFL models last 12,000 hours [3]. This value is described as an estimate on all lamp housings.

Power - The power of the lamps vary greatly within different models, so the power of the lamp in each case is described, and there is a comparison with other types of lamps. That way, the consumer can identify lamps equivalent to the ones he used to buy.

In the table above [4] there are examples of this comparison in terms of power and in terms of brightness or luminous flux. Both values ​​are described in the boxes, so it will be easier for the consumer to memorize the brightness value, since it remains similar among all types of lamps.

Luminous Flux and Temperature - The luminous flux must be chosen based on the need for light in space. If concentration and focus are required in such space, such as writing, reading, or cooking, the brightness of the lamp should be greater than in spaces such as a corridor where its use is not as essential.
The temperature, shown in Kelvin, is described in the lamp box and should be chosen considering the activity to be developed in space. In the residential sector the temperature values ​​usually range from 2700 to 5000 K. For a space with a lot of activity like cooking, it should be a higher temperature lamp, which can be called a cold color, with an average value of 4000 K. On the other hand, a space considered to be resting as rooms or rooms should install a lamp with a lower temperature, a hot-colored lamp, which on average has a value of 2700K [5].

[1] - Philips, “Iluminação.” - Available:
[2]- União Europeia, “Rótulo Energético.”
[3] - L. Liu, G. A. Keoleian, and K. Saitou, “Replacement policy of residential lighting optimized for cost, energy, and greenhouse gas emissions” pp. 11–13, 2017.
[4] - EDP, “Como escolher a lâmpada adequada,” 2016. Available:
[5] - Quercus, “Conselhos - Lâmpadas,” 2016. Available:

Buying the right lamp is important for reducing consumption, but there are simple behaviors that can further facilitate this reduction. To turn off lights when we are not using them, or make the most of natural daylight are some examples. They are small habits that can be gained and will not make any difference in our routine, but will certainely have a positive impact on the electricity bill at the end of the month!
It is generally agreed upon that the replacement of incandescent and halogen lamps should be immediately done for the most efficient lamps, ie LED's. Opting for LED instead of CFL in this replacement, the return in monetary terms of a light bulb of average use, is a period of less than 1 year, and it is predicted that this value will be decreasing.
In case you have CFL bulbs at home, you will need to balance the electricity spent with it the most, and invest in new LED bulbs. This balance will have to be made according to the life time that the CFL lamp will still have. As a basis to help, in terms of electric bill only, the price difference of a CFL lamp for an LED lamp, both supplying 470 lm, is 1.25 euros per year.
The luminous efficacy or light efficiency is the relation between the total luminous flux emitted by the source and the electrical power absorbed by it [1].
The greater the luminous efficacy, the less electric energy will be used to produce the same light flux. The units of this efficiency are lm by W, where lm represents the luminous flux in lumens, and W the power in watts.

[1] - EDP - Manual de Iluminação Pública

Big appliances

Appliances for cooking include the oven, microwave and electric cookers. Of these three types of appliances, only the oven has an obligatory and official energy label.

Energy Label - The energy labels associated with the oven show the name of the supplier and the model, the energy source of the oven, the energy efficiency class, the useful volume of the compartment in liters and finally the energy consumption per cycle in kWh / cycle, in conventional heating and forced circulation modes.

Usage and Maintenance - In the electric oven, we can apply some measures of use as a reduced preheating since the furnaces nowadays do not need long periods of preheating. Preferably, when using the oven, cook more than one meal and avoid opening the door during use, otherwise the energy consumption is increasing. In a cooking process of 250ºC, opening the door for 10 seconds implies an increase of 8% of the energy consumption [1].
When using the oven, choose materials such as ceramic and glass to bring food to the oven, which save time and energy in cooking. Always use the forced circulation function (ventilation), which allows to reduce the temperature of the oven by 10ºC and to accelerate the cooking process. At the end of the oven use, turn off 10 to 15 minutes before the time, which allows to take advantage of the residual heat to finish the cooking. Finally, avoid using the grill function, since it can double the energy consumption of the oven [2].
In terms of maintenance of this type of appliances, cleaning is strongly recommended. Checking the insulation rubbers to prevent heat loss is important and, if necessary, replacing them. Usually, the device's instruction manual tells you more ways to use and maintain it.

[1] - “Conselhos para uma compra Ecosave,” 2011.
[2] - Quercus, “Conselhos Utilização,” 2017.
Appliances for cooking include the oven, microwave and electric cookers. Of these three types of appliances, only the oven has an obligatory and official energy label.

Use and Maintenance - In the case of the microwave, there are small measures to be applied that can make a difference in the electricity consumption of this appliance. Not using the microwave to defrost food is a non-use of energy, opt for defrosting naturally. To heat foods choose the microwave, which saves time and 30% of energy [1]. The microwave is a device that has a relatively high stand-by, depending on the model, you must take this value into account and avoid using this energy by switching off the microwave.
Always covering food will allow a better distribution of the heat and prevent the appliance from being constantly dirty, and its cleaning is often important for its better functioning.

[1] - Endesa, “Conselhos para Poupar.” Available:
Refrigerating appliances include all refrigeration appliances such as refrigerators, freezers or combined cabinets.

Energy Label - The energy label of these appliances has some additional data to the energy class. Specifies the manufacturer and model of the appliance in question, energy rating and annual consumption in kWh / year. In addition, it specifies the sum of useful volumes in all compartments with temperatures in excess of -6 ° C, in liters. The sum of the useful volumes of freezing compartments (operating temperature less than -6 ° C), as well as the number of stars in the largest freezer compartment is also shown. If it does not exist, it will be indicated with -L and the star field will be empty [1]. The number of stars defines the maximum shelf life of the food, according to the temperatures reached in the freezers. Finally, it shows the noise emission level of the device itself, in dB.

Dimensions - The size of the household is important when buying these appliances and there are recommended values ​​for different numbers of people, as shown in the table below [2].

Price - If we compare two combined of the same brand and similar capacity, in this case 300L, the price for different energy labels will vary. The trend would be to buy a lower label like A+, instead of A+++, because they are already efficient labels, but cheaper. But in fact, if we compare annual consumption in kWh/year of the combined fuel for an A+ label would be 303 kWh/year, for an A+++ label would be 139 kWh/year. By making simple calculations, the yearly savings in terms of electricity, buying the most efficient appliance, would be approximately 37euros.
Since this type of home appliance has a lifespan of 15 years, buying the most efficient appliance would mean saving 555 euros. As the price difference between similar devices never rounds this value, the savings that are made at the moment, does not compensate for the savings that are made over the time of use of the device.

Maintenance - In terms of installation and maintenance, care must be taken with the overheating and temperature of the place to be installed. Do not place it near sources of extreme heat, such as ovens, and keep away from walls (at least 5 cm). Occasional cleaning of the ventilation area helps reduce overheating and allow better operation. In addition, check the joints of the appliances to keep the insulation intact and to verify that there are no unnecessary losses. In the case of freezers, when the ice sheet reaches 3mm it is necessary to thaw because the ice creates an insulation that will increase the consumption of the appliance by 30% [3]. These measures will allow not only a better functioning of the device as well as a longer lifespan.

Use - For the use of these appliances, there are basic measures that should be taken such as keeping the appliance door open for as little time as possible, every 10 seconds that a refrigerator door remains open there is an increase in the daily consumption of the appliance. between 0.2% and 0.8%. In the case of the freezer, those 10 seconds equals a daily increase of 2%. Defrosting the food inside the refrigerator contributes to the inside temperature of the refrigerator and reduces the daily electricity consumption of the refrigerator by about 2%. In addition, hot foods that need to be placed in the refrigeration appliances should cool off first and then be stored [4].
Filling appliances above their capacity will cause excessive consumption, but keeping them empty or well below their capacity will also contribute to excessive consumption than expected, since the air has more difficulty in absorbing the cold, ocillations of the interior temperature of the appliance will be higher and the appliance will have to work harder. It is important to note the set-up temperatures of the refrigerating appliances as each unnecessarily cold degree represents a consumption of 5% more than the essential.

[1] - Ecocasa, “Eletrodomésticos - Etiqueta Energética,” 2013.
[2] - “Conselhos para uma compra Ecosave,” 2011.
[3] - Enercoop, “Economies d’énergie.” Available:
[4] - “Conselhos para uma compra Ecosave,” 2011.
Energy Label - The energy label of the dishwasher has the following characteristics: the manufacturer and model of the household appliance in question, energy rating, annual consumption in kWh / year, annual water consumption in liters, efficiency class drying capacity, the nominal capacity in standard crockery and the noise emission level of the machine itself.

Price - Between an antique Class C dishwasher and an A ++ class appliance, you can save up to € 27 per year in terms of electricity. Assuming that these appliances have a useful life of at least 10 years, the savings would sum up to 270€ [1].


Use and Maintenance - Using the machine with full load and at lower temperatures, even if the cycles are larger, are two good measures. If the dishes are heavily soiled, immediately rinse them with water before putting them in the machine, it will prevent the residue from drying out and clinging to the dishes, and that they will all be washed in the normal cycles and at lower temperatures, preferably using the eco cycles when possible. In terms of maintenance it is important to keep the sun deposit and rinse aid full so that the machine performs best in the washing and drying phases. The filters must be cleaned regularly so that the efficiency of the machine is maintained and periodically cleaning the machine itself, using specific products for this purpose and acting as anti-limescale [2].

[1] - D. Proteste, “Máquinas de lavar e etiqueta energética,” 2011.
[2] - “Conselhos para uma compra Ecosave,” 2011.
Energy Label - The energy label of the washing machine has the following characteristics: the manufacturer and model of the household appliance in question, energy rating, annual consumption in kWh / year, annual water consumption in liters, total capacity the efficiency of the washing itself, the level of noise emission in washing and centrifugation, in decibels.

Capacity - The choice of the right capacity of these machines depends on several factors and it is difficult to define a value for the household in question. It depends on the frequency of use, and it should be taken into account any activities that require a constant frequency of washes are greater than expected [1].

Price - Between an old class C washing machine and an A ++ class device, you can save up to 19€ annually in terms of electricity. Assuming that these appliances have a lifespan of at least 10 years, the savings would sum up to 190€. So we have to think in the long term and the savings we can take from more efficient machines [2].

Use and Maintenance - There is some actions who can take when using these machines that allow the reduction of electricity consumption. Clothing, prior to washing, must be separated by level of dirt or wear, as non-heavily soiled clothing can and should be washed at low temperatures to avoid overheating the water. The machines and the current detergents are adapted so that very dirty clothes do not need washing at temperatures of 90ºC. A 90°C cycle consumes 3 times more energy than a 40°C cycle [3].
Using eco programs can help reduce electricity and use a higher spin values ​​during washing helps reduce laundry moisture and allows drying to be easier. Lastly, in terms of maintenance, cleaning the filter of the machine often helps not only the efficiency of the machine, but also its preservation.

[1] - “Conselhos para uma compra Ecosave,” 2011.
[2] - D. Proteste, “Máquinas de lavar e etiqueta energética,” 2011.
[3] - Enercoop, “Economies d’énergie.” Available:
Image is from ADENE´s website
Energy Label - Dryers in Portugal are not essential because the weather allows the clothes to dry naturally. Still, in the colder and wetter months there are those who choose to use tumble dryers. These machines have very high energy costs because they have a very large power. Therefore, the energy label is very important in this type of machines and a more efficient energy class will compensate much more compared to any other type of equipment. The difference between an A+ and a C label can be a saving of almost 70 euros per year [1]. Also the capacity should be adequate for the quantities of laundry to be dried.

Use - In the case of tumble-drying machines, the laundry should be put firmly inside the machine, never exceeding the maximum capacity of the machine. Do not open the doors during the drying cycle and preferably let the laundry dry naturally, it is the most economical way to dry clothes.

[1] - ADENE -
Recently, self-service laundries began to appear in different parts of the country and little by little people have joined. The question is whether to use these laundries instead of using the water and electricity at home in a machine of its own, compensates for it or not. According to DECO [1], going once a week to wash and dry 16kg of laundry a self-service laundry costs around 40 euros per month. The same task at home (eight washes and drying on 8kg machines) does not reach 14 euros per month, which will reduce to 4 euros per month if the dryer is not used and allowed to dry in the natural. Therefore, economically, it does not pay to use this type of laundry.
[1] - D. Proteste, “Lavandaria self-service é três vezes mais cara,” 2018.
Appliances for cooking include the oven, microwave and electric cookers. Of these three types of appliances, only the oven has an obligatory and official energy label.

There are those who choose to have electric stoves instead of the traditional and more common gas stoves. In terms of electric stoves, the induction hob is arguably the most efficient, yet it requires the highest investment. They are quick to heat and consume much less than other systems. In order to avoid excessive consumption of energy, it is necessary to choose a container with a diameter corresponding to that of the cooking area. To keep the hob always running at the same efficiency, it is necessary to clean it frequently and immediately after use [1].

[1] - D. Proteste, “Placas de cozinha: guia de compras,” 2016.

Small Electric Appliances

Small appliances include appliances connected to the kitchen, cleaning and other types of appliances not considered entertainment.

In terms of small appliances in the kitchen, such as kettle, toaster or coffee makers, the forms of efficient consumption are centered on the proper cleaning and maintenance of these appliances. Avoid using appliances unnecessarily, and above all check if there is any kind of energy efficiency associated with the appliance in question. With energy efficiency becoming so important on a daily basis, these smaller appliances now begin to have associated energy labels that need to be kept in mind [1].

In the case of devices associated with cleaning, the vacuum cleaner and the iron are the ones to keep an eye out. In the vacuum cleaner it is necessary to clean it properly, especially the bag and the filter of the device, where the obstructions can lead to an excess of energy consumption by the motor to obtain a suitable cleaning. With the iron, we can avoid overuse of it if we have a standard washing machine spin that will prevent the clothes from being totally crushed and separate the clothes before passing it, to avoid doing this work during the use of iron and to spend unnecessary electrical energy [2].

[1] - Enercoop, “Economies d’énergie.” Available:
[2] - Ecocasa, “Eletrodomésticos - Etiqueta Energética,” 2013. 
Multimedia devices refer to game consoles, radio, alarm clocks, televisions, television or internet box, fixed or portable computers and mobile phones. Frequent use of these appliances has generated the problem of wasted energy. This type of equipment is known for the stand-by and off-mode modes that occupy 5% of the annual electricity bill, and are a totally useless energy [1].

Stand-by is the operating state of the device that is consuming power, without being performing an active function. It is connected to the mains, in reactivation mode or connected and not in use. On the other hand, off-mode is the mode in which there is power consumption while the equipment is connected to an outlet, but without performing any function of operation. That is, when the appliance is switched off, but the connection to a socket [2] is maintained.

Older equipment will have a higher consumption than newer equipment, for example, VHS players, Internet or television box, old consoles and old equipment, are devices to be aware that may be increasing the final bill of electricity. An easier way of ensuring that you unplug these devices from the electrical outlets and not letting them waste power unnecessarily is to use either a power outage or a remote control. These sockets allow you to keep the devices plugged into a wall outlet, but there is no power to pass through the wall outlet, and therefore there is no unnecessary power consumption.

The correct use of this equipment can reduce its consumption, in addition to stand-by and off-mode, use of energy-saving modes or attention to energy labels of appliances that have them, is a good way to start reducing. Considering the habits in each residence, and the possible changes can be the first step to reduce consumption in this type of equipment, and old and little used appliances are a priority in this type of measures.

[1] - Ecocasa, “Equipamentos - Standby e off-mode,” 2014.
[2] - União Europeia “Comission Regulation (EC) No 1275/2008,” no. 1275, pp. 45–52, 2008. 

Air conditioning

Assuming a standard house of 120 m2 gross area, with 3 inhabitants, 7 windows and insulated with EPS (40mm thick), situated in the Lisbon area. The equipment of cooling and heating of the house are electric, to verify values ​​in economic terms of electricity, being the thermal comfort is guaranteed all the year in the dwelling, 20ºC in the winter and 25ºC in the summer. The values ​​of electricity savings in air conditioning and the time of return of the invested money are presented in the Table, comparing with the same construction having a null or very low insulation [1]. EPS is a material whose thermal performance in terms of insulation is in the average of the materials available for insulation [2].

Assuming that initially the house would have windows whose energy rating was an F, changing to type A or B windows, the return, in terms of price of electricity saved, would be made in 14 or 21 years, respectively. These costs are based on the price of the materials of the insulation solutions, without labor or application by companies, or accessory materials to fixation and support. To purchase these windows with energy-efficient labels with quality assurance can be used products from the Energy Product Labeling System (SEEP) [3].

[1] - D. Proteste, “Isolamento Térmico - Conforto com mais poupança,” Proteste 356, pp. 26–29, 2014.
[2] - ADENE - Agência para a Energia, “Isolamento de Coberturas.” 2016.
[3] - D. Proteste, “Isolamento Térmico - Conforto com mais poupança,” Proteste 356, pp. 26–29, 2014.
The reality of most of the Portuguese is that only the proper thermal insulation of the house is not enough for the air conditioning of the house to be the most adequate. The heating and cooling equipment is very present and represents 9% and 2% [1], respectively, of the final electricity bill. These equipment may or may not be electric, and there are several alternative renewable sources that can be used for air conditioning such as solar thermal, biomass and geothermal heat pump [2].

Energy Label - For electrical appliances such as air conditioning the concern for energy efficiency has brought mandatory energy labels, whether reversible or for heating or cooling only. This label describes the name and model of the supplier, the cooling or heating function (in this case there are both, because it is a reversible air conditioner), the energy efficiency class, the cooling / heating load in kW, the seasonal energy efficiency for cooling and heating, in SEER and SCOP, respectively, and in kWh / year. Finally, the emission of noise inside and outside the dwelling in decibels.
(SEER and SCOP are an indicative rating system for devices such as these that reflect true energy consumption, based on energy efficiency over an entire year.)

Not only with air conditioners, other devices to condition the thermal confort are energy-efficient and are becoming more and more mandatory, so be aware of the time of purchase. There is more and more equipment and more efficient equipment such as heat pumps. The high efficiency of these devices makes energy costs lower compared to other conventional solutions [3]. They have associated energy labels that allow them to perceive these differences, the label being similar to that of air conditioning.

Use and Maintenance - Regardless of the equipment installed in the house, its use and the behavior regarding the air conditioning can help to reduce unnecessary expenses. Example of these behaviors are the care with the windows in the different periods of the day in the different times of the year. In the summer, lower the blinds and close the windows during the hottest hours and in the remaining hours let the house air, opening the windows. In winter do the opposite, allow sunlight to come in to help warm the house. For a comfortable environment at home, regulating the climate control system to a comfortable temperature is essential, the use of excessively high or low temperature values ​​will require a greater use of energy, unnecessary for the comfort of consumers. The change of 1°C in the operating temperature corresponds to a saving of 7% in the energy consumption of the air conditioner, for example [4]. When using systems that radiate heat after switching off, taking some time off before leaving the room allows continuation of heating of the room, saving the unused final energy. The maintenance and cleaning of the systems allows its use to be the most efficient and the appliances have a longer life.

[1] - ADENE -
[2] - Ecocasa, “Climatização - Sistemas de Climatização,” 2014.
[3] - D. Proteste, “Bombas de calor para climatização: o que são?,” 2018. 
[4] - ADENE, “Ar condicionado,” Poupa Energia.
AQS represents 3% [1] of electricity use in households, a national average not too high since gas is still a very present method in heating these waters. There are some measures that allow to reduce the consumption of electricity referring to this type of equipment, like to set the water temperature between 50 to 55ºC, it is not necessary to warm to higher values. In terms of water types, depending on the amount of limestone in the water (depending on the region of ​​the country), have its own resistance or decalcify at least every 3 years to prevent a reduction in efficiency with deposits of limestone. Ensuring the insulation of the apparatus and adjacent pipes allows the water tank to remain at the desired temperature and prevents unnecessary heating of more water. This measure applies essentially to appliances whose placement is in spaces without air conditioning such as garages or cellars. Finally, in case of prolonged absence, 4 days or more, turning off this appliance ensures that there is no electricity to be wasted unnecessarily.

[1] - ADENE -
In terms of air conditioning, the way the house is built is very important for a reduced use of electricity in this sector. This measure is also the one that requires greater economic investment and is often incapacitated because it is a rented house or a building. However, the insulation of houses and glazing indicated can help reduce the 35% and 12%, respectively, in the part of the electricity related to the air conditioning [1]. Often the lack of concrete values ​​of saving and investment means that consumers have difficulty in moving forward with a decision on this measure.

[1] - "Ecofamílias 2009 - 2011,” 2011.