On the basis of the Basic Survey Electricity Consumption of Small Users [4] a list was composed of electrical appliances in a typical Dutch household. In this survey the degree of penetration, being the percentage of households that owns a particular appliance is also listed. In the present list, common appliances (with penetration > 50%) are assumed to be present, while less common appliances (with penetration < 50%) are left off the list. So we did not examine a household with 60% of tumble dryer and 2% of Jacuzzi hot tub. The resulting list is shown in table 1.

The electricity consumption of the remaining appliances adds up to 3670 kWh/a, which is somewhat higher than the average electricity consumption of the Dutch dwelling (3350 kWh/a). How can we reduce this electricity consumption? A number of steps are discussed below.

Step 1: Elimination of standby electricity

In an average household, electricity consumption of standby modus makes up approx. 10% of the total consumption, which can be significantly reduced by application of so called ‘stand-by killers’. Different types of stand-by killers are available on the market. However, a more structural approach on the level of building related measures would entail the implementation of a series of wall outlets of a different colour (e. g. green) that can be switched off during the night or in absence of the occupants.

By eliminating all standby electricity the annual electricity consumption of the appliances on our list can be reduced by approx. 400 kWh/a (11%). This is perhaps an optimistic figure to achieve in practice as not all appliances lend themselves to standby killers (in particular those with a clock or a timer). Also some appliances’ standby consumption will only be reduced during the night.

Step 2: Replacement of appliances by the most energy efficient variant (A-label)

This step shows the potential of reducing electricity consumption with the state of the art technology. Table 1 shows that the largest gains in terms of kWh/a are achieved by application of low-energy light bulbs and replacing the refrigerator and the freezer with an A-label combined refrigerator-freezer.

With these and a number of other small replacements, the average Dutch tenant can save another 1016 kWh/a (28%).

Step 3: Low energy or renewable energy appliances

When considering the appliances remaining after step 2, a number of these require heat that is supplied in the form of electricity, such as the dishwasher or the washing machine. Offering heat from a boiler, a micro Combined Heat and Power plant (CHP) means that we avoid the heat losses in the electricity plant (50%) where the electricity is being generated. An even more desirable option is to use solar heat from a solar collector. This option is further discussed in chapter 3.2.2. Of course, care must be taken to reduce as much as possible any heat losses from the piping between the heat source and the dishwasher / washing machine.

Another major consumer of electricity in dwellings is the tumble dryer. Gas fired dryers are a good alternative or, more ambitiously, a drying room fed with waste heat from e. g. the refrigerator.

Further reductions are possible: research is being carried out on dishwashers that require no more than a single cup of water. Using the right soaps/enzymes, washing could be carried out at much lower temperatures, saving on the need for water heating. Drying at low temperatures, using a fan rather than a heater also lowers the heating demand.

Refrigeration is also a major electricity consumer. This could be done more efficiently using a cool room or cool cupboard in the house, that is efficiently cooled with ground heat exchangers or — in wintertime — by the evaporator side of the heat pump. Implementation of a top lid on the refrigerator avoids losses when opening the door. A carousel system can provide easy access to all wares stored.

A bonus for all these savings is a reduction in internal gains, which will reduce the risk of overheating of the dwelling during the summer.

It is doubtful whether we will achieve a factor of 4 in the reduction of domestic electricity consumption with the three steps described above. That means that in order to reach our target of 65 kWhp/m2a, additional measures will be necessary. This is the next step in the Kyoto Pyramid.