Monitoring Electricity Usage

The government is keen to encourage meters which inform users of their continuing energy consumption. This is easier to do for electricity than for gas or oil. There are now several devices which can display the electrical consumption of a house. It is of little use to provide this information at the main meter, as these are not normally easily visible so all current units sense the consumption at the meter and use a wireless link to send the information to a portable display which might be 30 metres away.

It has been claimed that some users have saved up to 25% on their electricity bills using such devices. However, the amount you save will depend upon how conscientious you are in using the monitor and on taking action to turn off or reduce the consumption of non-essential appliances. If you do not need a permanent monitor in your home, you may consider it would be sensible to share a monitor and its cost with your neighbours.

Energy monitors can now be ordered from several suppliers.

OWL monitor The Blewbury Energy Initiative working party found, evaluated and can recommend an easy to use monitor, which displays current consumption in cost or kWh per hour. This is now known as the OWL monitor (details: www.2saveenergy.com). The monitor was developed by an Australian company Wireless Monitors Australia Pty Ltd (WMA). A large number of these monitors have been in use in Australia and New Zealand. The company has now been purchased by 2save Energy plc, a company based in Newbury, England. This portable wireless monitor in July 2008 sold at £34.95 from www.theowl.com. The Blewbury Energy Initiative was able to get these at a discount on the original price. providing we ordered a minimum quantity. We collected enough orders for a bulk purchase in August 2006.

EFERGY monitor This newly introduced monitor is similar to the OWL. It can be viewed on www.efergy.com and in July 2008 was about £44.95. It appears to provide the key features for monitoring electrical energy consumption with the important addition over the OWL of a record of total consumption by day, week and month. It has not been tested by the Blewbury Energy Initiative working party.

WATTSON 01 monitor This monitor is more expensive at around £150. It is produced by DIYKyoto and can be seen on www.diykyoto.com. The display part of the system is an eye catching gadget with flashing lights as well as the display. It can feed the data it collects into a computer program. It has not been tested by the Blewbury Energy Initiative working party.

CurrentCost monitor This monitor is being trialed by Scottish and Southern Energy, and is supplied free of charge to customers who switch to their "Better Plan" - which is currently at the same rate as their normal energy tariff. Two members of the Blewbury Energy Initiative have recently switched to this plan and so far are impressed by the CurrentCost monitor. The transmitter is battery powered but the batteries are expected to last several years. The display requires a mains plug and consumes about 1 watt. The display device keeps a record of past consumption, and can hold data for 3 months, the data on the display unit is retained if there is a power cut, but the clock stops for the duration of the cut. The display unit also provides a data feed over a serial cable to personal computers. However the software to accept and analyse this data is not yet released (August 2008). The monitor is described on the www.currentcost.com website.

Single Device Energy Usage

There are now several single socket energy monitors being sold, priced at around £15. Typically they plug into a 13 amp mains socket, and provide a 13 amp socket to feed the load to be monitored. All monitors will present the instantaneous power being drawn via the socket plugged into the monitor. They may not detect low currents such as those taken by most phone chargers when no phone is being charged. However it is important that they can measure down to about 1 watt, as 1 watt taken continuously costs about £1 over a year. A very desirable extra feature is the ability to totalise the energy used over a period, and not all monitors provide this. If the device can totalise in this way, the ability to retain information when the device is unplugged is also useful as this can avoid the need to view the readings in awkward places, however this requires the device to include batteries. The Brennenstuhl Electricity Meter (illustrated) has been available for some years and provides both the total energy used and data storage of this data. It has a list price of £19.99. It has not been tested by the Blewbury Energy Initiative.

Energy Saving Transformers are probably not suitable for Domestic Use

The power supply in Blewbury is a fairly steady 240 Volts, however the electrical equipment sold in the UK must be designed to work with voltages down to 216 Volts, and in time EU regulations will require that devices must run with as low as 207 Volts - actually in a range of 230 volts + or - 10%. Thus it is possible to reduce the power supply in a house and all devices would still work. A reduction by 7% is often suggested leading to a nominal voltage of 223. With many devices reducing the voltage by 7% reduces the energy used by nearly 14%. The benefit of this depends on the use of the electricity:

• Heating applications will have 14% less power, thus fan heaters, clothes dryers, ovens and hot plates will take longer to be effective
• Lighting applications will get less power. Incandescent lights will be dimmer and will last longer. Fluorescent lights will be less affected.
• Other devices such as computers, televisions, motors and possibly freezers are likely to operate satisfactorily while taking less power.

The main disadvantages are the cost of the transformer required and the energy it takes even on no load, which might be about 1% of peak load. The normal load in a house is typically a very small fraction of the peak load. Thus a transformer rated at 7.5kVA, which is the minimum likely to be specified, might introduce a standing load when the building requires no power of 1% of this or 0.075 kW. This continuing loss may well exceed any gain made from the voltage reduction.

Energy saving transformers can be appropriate in industrial and commercial environments

The idea is clearly relevant to industrial and commercial sites. Here the load is more continuous so the transformer losses at low loading are less significant. Also transformers applying to a three phase supply can achieve power smoothing and other benefits. For one supplier see Power Perfector

A separate but related idea suitable for industrial and commercial applications is exemplified by the Fluoresave device. This is specific to fluorescent light installations. It maintains full mains voltage when there is no load, but reduces the voltage to the lights after they have been switched on. It increases the voltage again for a time if the load changes. The physics of this device arises as fluorescent lights require a large voltage to strike the light, but then need much less voltage to maintain the plasma.

Grants for Energy Improvements

For up to date information on the grants available in Blewbury, the best source is probably the Vale of White Horse District Council Vale Energy Team. They can be contacted on the free phone number 0800-592865 email vet@whitehorsedc.gov.uk.

Cocoon also provide a similar service for this area.

If your energy bill currently exceeds 10% of your household income, you are very likely to be able to get improvements to reduce the cost of heating paid for.

An effective system for encouraging energy improvements would be easy to access, easy to understand, stable and would encourage the most effective ways of saving energy.

At present:

• a number of different organisations may be offering grants or other assistance,
• each organisation sets its own conditions,
• the availability lasts until the sponsoring organisation has used up the funds it has allocated, and
• the less effective systems often attract the higher incentives.

The sources of grants can include:

• local government,
• the Department of Business, Enterprise and Regulatory Reform (DBERR) and
• energy suppliers.

The assistance can be:

• a three for two offer on DIY insulation supplies at nominated retailers,
• a low fixed price for insulation work,
• a fixed sum towards a professional installation of energy generation equipment such as for a solar panel installation. The sum depends on the technology being installed. DBERR sets an upper limit of £2,500 per household.

The current DBERR scheme of support for energy generation is described in www.lowcarbonbuildings.org.uk/how/householders. Their grants for energy generation are only available if the applicant has already

• a. insulated the whole of the loft of the property to meet current building regulations e.g. 270mm of mineral wool loft insulation or suitable alternative
• b. installed cavity wall insulation (if you have cavity walls)
• c. fitted low energy light bulbs in all appropriate light fittings
• d. installed basic controls for your heating system to include a room thermostat and a programmer or timer.

10 Free Ways to Save Energy

Turning your thermostat down by 1 degree centigrade could cut your heating bills by up to 10 per cent and save the average home around £40 per year. Is your water too hot? If you have a separate hot water tank, and this is large enough, the cylinder thermostat should be set so that you do not need to add cold water when using the hot tap. Close your curtains at dusk to stop heat escaping through the windows. Always turn off the lights when you leave a room. Don't leave appliances on standby and remember not to leave appliances on charge unnecessarily. If you're not filling up the washing machine, tumble dryer or dishwasher, use the half-load or economy programme. Only boil as much water as you need (but remember to cover the elements if you're using an electric kettle). A dripping hot water tap wastes energy and in one week can waste enough hot water to fill half a bath, so fix leaking taps and make sure they're fully turned off. When cooking choose the right pan size for the food and the cooker, cut food into smaller pieces and put lids on pans as the food will then cook a lot quicker. The sun is the most readily available source of heat there is - and the cheapest! So make the most of it by opening internal doors of any rooms which get more sun than others and let the warm air travel through your home. Avoid using tumble driers and radiators to dry your clothes when possible; on nice sunny days clothes can be dried outside.

Draught Proofing What is draught proofing? Draught proofing is the process of filling in unnecessary gaps in the fabric of a building to reduce heat loss and discomfort due to draughts. You can draught proof windows, doors, letter boxes & keyholes. You can also fill in gaps in walls due to plumbing and gaps in floorboards or skirting boards. The materials used for draught proofing include foams, brushes, sealants and thin sections of rubber, plastic or metal. What are the benefits of draught proofing? Draught proofing is a cheap and cost-effective way to reduce your heating bills and make your home feel warmer. Draught proofing is also very effective at eliminating cold draughts that can make you feel uncomfortable and cause you to turn up the heating. You can easily check where in your home needs draught proofing. Hold the palm of your hand up near windows or doors. If you can feel any cold air coming in, then it's worth draught proofing that area; it'll stop the cold air getting in and the warm air getting out. How much does draught proofing cost? Draught proofing costs very little if you do it yourself, but contractors or the local handyman should not be expensive. If you decide to fit draught proofing yourself, you can buy the materials in most DIY stores; make sure they conform to standard BS7386. What else can I do to stop draughts? Try hanging thick curtains in front of doors and windows. They will stop heat escaping and prevent cold air from entering, so your home will feel warmer and more comfortable. Shut the curtains at dusk to keep the heat in. Curtains with a thermal lining will be even more effective and placing material "snakes" at the bottom of doors will also help stop draughts. Don't forget the letter box and keyholes. BUT . . . A word of warning - don't go mad! Your home needs ventilation to be safe, to stop it becoming stale and stuffy, and to eliminate the possibility of condensation and mould growth. Ventilation is essential if you have solid fuel fires, gas fires or a boiler with an open flue. So check air bricks for blockages, do NOT block them up. Ventilation is also essential in kitchens and bathrooms, so if there are not other means such as an extractor fan, don't draught proof there either.

Insulation Methods

The village energy survey conducted earlier this year revealed that most homes had some loft insulation but nearly all could benefit from a top up. Cavity walls are often not filled with insulation. There was also little solid wall insulation, which whilst difficult, is possible in many cases. All this adds to fuel bills and impacts on the environment as more fossil fuel is used to keep warm. Simple additional insulation measures can be effective and inexpensive.

Through the roof - 270mm (10.5 inches) of insulation is recommended for lofts. Mineral wool, fiberglass, sheep's wool and recycled paper products all work well. Insulation can be installed by a contractor or you can do it yourself. If doing it yourself:

• Wear a face mask, goggles and protective clothing.
• Leave sufficient gaps around the eaves to avoid condensation.
• Do not insulate under water tanks that may freeze,
• Ensure all pipe work is insulated and also
• Insulate the loft hatch.

Through the walls - Wall insulation can reduce heat loss through the walls by two-thirds and make your home more comfortable. Cavity walls can be safely filled with insulating fibre, beads or foam. For solid walls internal insulation can be highly effective. Typically an insulated board is fixed to the wall. This means rooms have to be redecorated and may lose architectural detail. The work can be done by competent DIYers and may be done on a room by room basis at the same time the home is redecorated. External insulation is more difficult, it usually needs planning permission and should only be carried out by specialist companies.

Cocoon is a "free, independent, advice service run by two not-for-profit agencies dedicated to saving energy in Beds, Berks, Bucks, Herts and Oxon". Cocoon can providing advice on grants including further discounts for those on a range of benefits. Cocoon can also assist in getting quotations for cavity wall and loft insulation. They refer callers only to reputable installers. Prices for insulation work are normally below £200. Contact the scheme by phoning free on 0800-48777 or visit their website www.cocoonyourhome.co.uk.

Heating Controls that Save Energy

Energy efficiency in the home is not just about improving levels of insulation. Modern, easy to understand controls, designed to ensure that the boiler is only working when heat is needed in the home are every bit as important.

Good heating control package will normally include the following:

• an electronic timer or programmer
• a room thermostat
• thermostatic radiator control valves (TRVs), and
• separate thermostatic control on the hot water system

Additional controls that may be worth considering to get the very best from a central heating system include:

• intelligent heating controls
• programmable thermostats
• a weather compensator
• a boiler energy manager
• full zone control, and
• remote control

Basic controls

The timer or programmer

The electronic timer or programmer decides when the boiler is able to run. It is not true that boilers work best when they are running continuously or that energy is saved by leaving the heating on all day, even if the home is unoccupied. Whenever the boiler is firing it is using energy, and whenever the home is being heated to a temperature above that outside, it will be losing heat to the outside world. In spring and autumn there is no need to keep the heating on all day; a reasonably well insulated home can be left to cool down slowly with the heating timed to come on perhaps an hour or so before people return home from work.

A seven day timer is also strongly recommended, so that it is possible to set a different heating pattern for weekdays and weekends. Some programmers incorporate built in thermostats and temperature sensors. These need to be sited in a living room rather than by the boiler, but can often represent a good investment.

The room thermostat

This is best located in a living room, rather than the hallway, as is commonly done, as the hall temperature can be affected by the front door being used. The thermostat records the home's temperature and if it is at or above the set level (and 20°C/68°F is usually adequate) stops the boiler from operating the central heating.

Thermostatic radiator control valves (TRVs)

These switch individual radiators on or off, depending on how warm the room that they are located in is. They usually have a fat valve at one end, marked with a * and numbers from 1 to 5. The * setting is to protect against frost; it will typically leave the radiator switched off unless the temperature falls below about 6°C. For a normal living room, the setting of 3 or 4 is likely to be about right; for a bedroom a cooler temperature will normally suffice. Turning the dial up when the radiator is already on will not increase the room temperature! It is not a good idea to have a TRV on the radiator in the same room as the main thermostat, as if it turns the radiator off at a lower temperature, it can mislead the main thermostat into thinking that the house is cooler than it really is.

Thermostatic controls on the hot water system

This section only applies to systems with a separate hot water tank. Firstly, it is most important that the hot water can be controlled by the programmer separately from the central heating. Some older systems only allow the heating to run when the hot water is on; this can be quite wasteful of fuel. Secondly, there should be a thermostat on the hot water tank - this is usually strapped to the outside fairly near the bottom. This controls the water temperature - it should not normally need to be set higher than 60°C.

The room thermostat and the hot water thermostat should be wired up to the boiler in what is known as an "interlock". This means that if both the house and hot water are at temperature, the boiler will be switched off. If this does not happen, when the water temperature inside the boiler itself falls, an internal thermostat will cause the boiler to fire to heat up this water - a process known as "dry cycling". All the energy used in this cycle is wasted as it is not used for any useful purpose.

More advanced controls

Intelligent heating controllers

Intelligent heating controllers, such as the "Dataterm", combine several of the functions above and can also learn how long it takes for a house to heat up in different weather conditions. These also often allow for different temperatures to be set between day and night. They give the very best control over central heating, although they cost somewhat more than normal controls.

Programmable thermostats

Programmable thermostats allow the target temperature of a heating circuit to be varied over the day, for example with a warmer temperature in the early morning and in the evening, a cooler temperature during the day, and a low setting at night. Often these provide for four different time periods and temperature settings during weekdays and another four over weekends. More complex versions allow different settings for every day of the week.

Weather compensators

These measure the temperature, either internally or externally, and delay switching on the central heating on milder days. Simple ones are quite inexpensive and replace a normal room thermostat; they are well worth considering, although the programmer will appear to need to be left on for longer periods when they are first installed.

Boiler energy managers

There are many kinds of boiler energy managers on the UK market, ranging from simple devices that delay a boiler firing (and work rather like just turning down the thermostat!) to complicated ones optimised for a particular model of boiler. The general advice is that simple strap-on devices are probably not a good investment, but that if a boiler manufacturer recommends one for use with a specific model of boiler, then they are worth fitting at the time that the boiler is installed.

Full zone control

Most homes have a single heating zone - the only controls in the rooms are by TRVs. However the need for heating in the main living rooms can be quite different from that in bedrooms, with the latter requiring lower temperatures for longer hours. At the time a new central heating system is installed, it is possible to fit a full zone control that has different pipe loops and separate thermostats for two (or more) areas. This can save significant amounts of fuel in larger houses.

Remote control

Some heating control systems can be controlled remotely over the Internet, so for example a single occupier can turn on the heating when they are about to return home.

Energy Myths or Simple Truths?

A number of common assumptions about saving energy are myths, while others are largely true. The following assumptions are based on a similar list from the National Energy Foundation.

1. It uses less energy if you leave fluorescent lights switched on

MYTH - If you are out of a room for 5 minutes it always saves energy to switch fluorescent lights off.

2. It is wisest to leave your immersion heater on 24 hours a day

Sometimes TRUE, sometimes a MYTH - Provided your hot water tank is properly insulated, and no water is being used, the tank should only cool by about one degree every few hours. This makes very little difference to the rate of energy loss through the insulation, so the extra cost of maintaining hot water continuously for use as required is negligible. If your tank is poorly lagged (with thin foam or tank jacket) then switching the heater off when no hot water is likely to be used, e.g. overnight, will save energy. Reducing the temperature setting of the thermostat controlling the immersion heater always saves significant energy.

3. If you have thermostatic radiator valves you don't need a room thermostat

MYTH - Thermostatic Radiator Valves will only switch the flow to a single radiator on or off. They do not stop the boiler from firing and so using energy. Energy is saved if the boiler runs only when it is needed for heating or for hot water. This requires a room thermostat. The room thermostat should not be in a room which also has Thermostatic Radiator Valves or the room may never get hot enough to switch off the boiler.

4. It's cheaper to use an immersion heater in the summer than to heat water from your central heating boiler

Usually a MYTH - As gas costs about 25% of the cost of electricity providing the same energy, a boiler would have to be less than 25% efficient before electricity is cheaper. If you have a modern gas boiler controlled by a hot water tank thermostat, then it will be better to use the boiler all year. With oil boilers the benefits are less but are still likely to be significant.

5. Leaving your PC screen switched on during a break prolongs its life and doesn't waste much energy

MYTH (mainly) - Whilst in operation, cathode ray tubes typically use between 30W and 200W. Screens do not use less energy when they are in screen saver mode (that's just designed to stop the phosphor coating being damaged). Some personal computers go into sleep mode after about 20 minutes if they are not being used, but even in sleep mode they still use some energy. The end of life of a cathode ray tube is nearly always caused by obsolescence not failure. LCD screens typically require less energy, however there does not seem to be any reason to leave them on.

6. Use less power - take a shower!

Sometimes a MYTH, but sometimes TRUE - If your shower uses the same source of hot water as your bath, and you use less hot water when taking a shower, you will use less power. However if your shower is heated electrically and your bath water is heated by a cheaper fuel, the shower must use considerably less water than the bath before there is any saving. If the shower is over the bath, and you put the plug in, you can find out whether your shower actually uses less water than the bath you might have taken.

7. Strapping on a gizmo to your boiler can save you at least 10% from your heating bills

MYTH - High-pressure salesmen claim amazing improvements in boiler efficiency if a simple device is placed round the gas pipe. Such a major improvement would be very easy to prove in objective controlled tests from an independent laboratory, however the salesmen will not be able to provide such data. Instead the salesman will cite "satisfied customers".
A device which increased the calorific value of a fuel by 10% would be hailed as a major advance and would be installed worldwide. Think of the money this would save a power company. This cannot be claimed, so the sales pitch is that the device improves the efficiency of the domestic boiler.
Generating a 20% improvement in a condensing boiler which is already 90% efficient would clearly be impossible. Much of the lower efficiency of older boilers is for reasons such as the discharge of steam in the flue, and the need to heat the mass of the boiler, which cannot be affected by any supposed change to the way the fuel burns. How likely is it that a reasonably maintained boiler is not burning 10% of the fuel it is using? If it was operating so badly, how likely is it that the problem can be cured by any minor change to the fuel?

8. Big freezers cost more to run than little freezers

Usually TRUE, but not always - Small freezers are often upright models, which lose a significant amount of cold air whenever the door is opened. It can take as much as 30 minutes for a freezer to regain its temperature after a door has been opened for a minute. Chest freezers, with a lid opening - and typically thicker insulation levels - will often use less than half as much energy for a given volume of food storage. So a 125 litre upright freezer will often use more energy than a 250 litre chest model. If you have empty space in either type of freezer, it's best to fill it, for example with empty cardboard boxes, to stop air flow when the door opens.

Green Electricity Tariffs

Most of us are familiar now with changing our electricity supplier and many would like to sign up to a 'Green' tariff (where the electricity comes from a renewable source, such as hydropower or wind turbines), but what exactly are these and are they worthwhile? There are two types of tariffs that you can sign up for: Green Supply - where the electricity company ensures that for every unit of electricity you use, a set proportion of green electricity is generated. However, as supply companies have a Renewables Obligation set by Government to supply a minimum level of renewable electricity (currently around 5%) some companies use the renewable electricity they sell as a 'green' tariff towards meeting their own Renewables Obligation or, through certificate trading, to allow other suppliers to meet theirs. The net effect of this is that although you are getting more renewable electricity, everyone on standard tariffs is getting less. Green Fund - where the electricity company invests some of what you pay on your bill in new renewable energy projects. However, many supply companies have already made a decision to invest in renewables, to ensure they can meet their Renewables Obligation or for other commercial reasons, so signing up for their 'green' tariff might not have any real effect, except perhaps to boost their profits.

Given this confusion, if you are really concerned about making a difference, then we suggest action in your own home is the best option, including anything from installing low energy lightbulbs, through to installation of solar photovoltaic (PV) panels that generate electricity. Every action counts.

Energywatch is a government initiative to monitor all issues around the supply of electricity and gas in the UK. It provides a summary of the different green tariff schemes available on www.energywatch.org.uk/help_and_advice/green_tariffs/tariff_types.asp.

The best source of information if you wish to switch to a green tariff is probably Green Electricity at www.greenelectricity.org.

Devices on Standby

Many electronic devices are left powered up when they are not being used. An average household may spend £40 a year just keeping devices in this state. Computers, Set top boxes and internet routers and other devices may be left running to avoid the inconvenience of starting them up when they are required. Some devices have a standby state in which the device can be restarted conveniently. For example a TV typically goes into a standby mode when switched off by its remote controller. It may not be obvious that the device is in a standby state. For example a computer printer can be put into a standby mode by the off switch on its console. Some printers continue to take nearly as much energy when "switched off" as they did when switched on but not being used. If left in this state such a printer typically takes about 10 watts or about 100 units a year at a cost of about £10 per year.

The AC adapters and chargers which are typically built into mains plugs also take noticeable power when the mains is connected even when they are in the no-load state, and not connected to the device they are designed to support. The only reliable way to ensure a device is not taking electricity is to switch it off at the mains.

Other devices often left in a standby mode include DVD, CD and VHS players, amplifiers, video players, computer monitors and speakers, microwave ovens, washing machines, tumble driers and dishwashers.

It is estimated that a 500MW power station needs to be run continuously to power all the devices left on standby in the UK.

Devices on standby will be generating heat and thus will slightly reduce the need for other kinds of heating. However electricity is a very expensive form of heating, and the heat is not needed for much of the year.

Those who enjoy the Dragons Den programs on TV may remember the most successful presentation to them was of a device to switch off all the devices which otherwise would be on standby. All the dragons wished to invest. Although this deal fell through the device is now available as Standby Saver (www.standby-saver.com) at £21.95.

There are also alternative products such as Bye Bye Standby (www.byebyestandby.co.uk).

The Energy Initiative has not tested either product. The following article was researched by a member of the Initiative.

Standby Energy Consumption

A member started this exercise to learn more about how much electricity is wasted by leaving devices powered up and on standby. He was thinking in terms of two situations: devices that do not really need to be left in standby (for example a TV that comes on almost immediately, the only advantage being that you have to go to the TV instead of using the remote control), and devices where there is some advantage in leaving them on, for example a computer that takes a while to reboot, or a hard-disk video recorder, which also serves as a digital TV set-top box, and which often takes quite a long time to update the on-screen programme guide if not left on.

Although not all brochures specify the power used on standby, it was already obvious that there are very big differences. In addition, some of the devices do not have on-off switches. However, in the course of doing the measurements another serious waste of energy was discovered, in the form of the electronics built into the mains plugs to convert mains AC to a low voltage supply for the device. These are often called mains adapters but below are referred to as external power-supply bricks.

Readings were taken with a Maplin 'monitoring socket' that you plug things into. It goes down to 1W, but may not be accurate at those levels. However, it easily distinguishes a 1W device from a 4W or 10W one. A device using 1W continuously on standby consumes about 8.8kWh per year if on all the time. At 9p per kWh this costs about 80p per year more than turning it off. (Or think of it as 1W left on costing nearly £1 per year to run.) Before the work started started, the ElectriSave monitor showed minimum consumption of the entire house as low as 50W, on the rare occasions when heating, fridge, etc. were all off. Many devices were normally switched off. But as will become evident, a large fraction (possibly around half) even of this remaining 50W can be eliminated. We see in the table a variety of situations. Some devices use a lot of power in standby mode, well above the European target of less than 2W. Other devices consume very little power, and leaving them in standby is not serious. Not fitting a mains switch, especially when the device consumes several watts minimum, should not be allowed - there is no good reason to leave most of these things on. Two items (tape cassette deck and halogen lamp) consume substantial power even when switched off, despite not having external power-supply bricks. A switch in the mains lead fixes this.

Although some of the numbers were surprisingly high, the standby situation will mainly motivate us to try to switch a few more items off, and to fit switches in the mains leads of devices with no switches.

What had not been appreciated was just how many external power-supply bricks there were, and how much they consume. You may think a device is switched off, but it is actually consuming a few watts all the time unless it is switched off at the mains socket, which is often located out of easy reach. Looking globally, the UK is one of the few countries which even has switches on its mains sockets - most of the world does not, so switching external power-supply bricks off is not an option. In all the talk about how much energy is wasted by standby no one seems to mention this.

The devices measured