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HOME PAGES GLOBAL WARMING WHAT YOU CAN DO GREEN ISSUES BACKGROUND THE INITIATIVE |
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This page offers advice on effective energy saving in the home: free or low-cost savings, what can be achieved by home improvements, and some more detailed discussion on heating, windows, fridges and freezers, appliances, and leaving items on standby. The cost savings to expect are on a separate page. Finally, we list the possibilities for domestic green energy generation. |
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Efforts to Tackle the Problem We should try to stop using fossil fuels and emitting large quantities of greenhouse gases as soon as possible. As this is difficult to achieve, various practical targets have been proposed internationally. The UK aims for an 80% reduction in greenhouse gas emissions by 2050. Some of this reduction can be achieved by using energy more efficiently. About 27% of the energy in the UK is used in domestic homes, where considerable energy savings can be made. Some of these also save money, and as energy prices rise they become even more cost-effective. The National Energy Foundation website provides a good overview on this subject. As a more complete solution, a large number of different sources of clean energy are being explored. 
Free or Inexpensive Household Energy Savings The following changes cost nothing or very little, and can generate significant energy savings. Lighting 
Electric lighting is the largest consumer of electricity in many households. Switch off lights when they are not being used. Use low-energy lights. Replace all incandescent bulbs that are switched on for more than a few minutes at a time with low-energy bulbs (also called CFLs – compact fluorescent lamps), or install conventional fluorescents. Replacing just one 100 watt bulb which is used for 4 hours a day by a 20 watt low-energy bulb would save about 115 kilowatt-hours ("units") a year. At 12 pence a unit this would save £13.80, so you save the cost of the bulb within months. Low-energy bulbs last much longer than incandescent bulbs, so although they can be more expensive to buy (look for special deals) the cost of purchase over their lifetime is similar, and there is also the advantage of not having to replace them. Low-energy bulbs come up to full brightness more quickly than they used to, and there are now some models that work with dimmers or that replace halogen lamps. The range of low-energy bulbs in the shops can be limited, but we have a list of suppliers offering a much wider range. There is much more information about low-energy lighting on our lighting page. Heating 
Reduce the central heating temperature setting by 1 or 2 degrees. Even small changes make very considerable energy savings – a 1°C reduction can save about 10%. Switch heating off or turn the thermostat down when no one is at home. Reduce hot water temperature by turning down the thermostat on the tank. If you always have to mix hot water with cold water you are almost certainly overheating the water and wasting energy. Have showers rather than baths as they use less hot water. Insulate ("lag") all hot water pipes, particularly the ones between the boiler and the hot water tank. Do not heat rooms that are not being used. Close curtains at dusk. Stop draughts by filling in gaps under skirting boards with paper or mastic. Install draught-proofing strips on windows and doors. Energy-Saving Home Improvements The savings to expect from these measures are discussed separately, on our cost saving page. There are grants available for many of the following items, making them either inexpensive or in some cases free. A list of schemes is available from the Vale of White Horse Energy Team. 
Increase roof insulation. About a third of heat loss can go through the ceiling. Where possible, increasing the thickness of insulation to 270 mm (11 inches) is recommended, and if this is not possible you should certainly have at least 100 mm (4 inches). If you have less than 100 mm, increasing it can give the most rapid return on your investment. Add a jacket to the hot water cylinder if it does not have a foam outer coating. At least 75 mm (3 inches) and preferably more is recommended. This is cheap, easy, and pays for itself within months. Fit cavity-wall insulation. Install a condensing boiler. If your current boiler is over 10 years old, this should reduce fuel usage by perhaps 35%. All new boilers must now be condensing models. There is more information on boilers and heating below. If you have an old boiler you may qualify for a grant from the government's boiler scrappage scheme – details are given here. Add automatic heating controls. Room thermostats (especially programmable ones), hot-water cylinder thermostats, timer/programmers, and thermostatic radiator valves are all useful, saving energy while increasing comfort. Fit double glazing or secondary glazing. This halves heat loss through windows, reduces condensation and noise, and is more comfortable. However, for saving energy it is not as cost-effective as the other suggestions. There is more information on windows below. Get a free energy check A simple, free check that suggests what you can do to improve your home and how much it might save is offered by the Energy Saving Trust. Condensing boilers and heating 
Modern boilers are lighter, so less metal has to be heated up when they are turned on; this is more efficient especially in summer when the boiler might be used intermittently to heat water. All new boilers, both gas and oil, must now be now condensing boilers, which further increases efficiency by extracting the heat from the steam generated in combustion. The efficiency of these reaches about 91%, compared to perhaps 78% or less for elderly boilers. Condensing boilers collect heat from the flue gases and use it to pre-heat the water returning to the boiler. If the difference between the flow and return temperatures is too low, little benefit is gained from the preheat, so the difference is controlled automatically by adjusting the water flow and heat input. Condensing boilers gain most energy from condensing the steam in the flue gases if the water being drawn into the boiler starts cool. With higher input water temperature, more steam will escape as vapour and less energy will be captured through condensation. Efficiency begins to drop above about 40°C, and falls off rapidly if the input water temperature exceeds 50°C. A generous area of radiators helps to cool the water before it returns to the boiler. A lower output water temperature also results in a lower input temperature, and this can still provide the heat needed if the radiator area is large enough 
Heating water with a gas or oil boiler in summer should be more efficient than using an electric immersion heater, because electricity costs several times more than gas or oil for the same energy. A boiler and the pipework connecting it to the hot water tank would need to be very inefficient for it to be more expensive for water heating than an immersion heater. Combi boilers (left) are a good option for smaller properties. They drive the central heating system and also supply hot water directly, avoiding the need for a hot water tank and the associated heat losses. As the water is heated when it is required, the flow available is more limited than from a hot water tank. Underfloor heating allows condensing boilers to run at high efficiency, as it provides both the desirable features of a low temperature heat output and a large radiating area. It can be combined with conventional radiators and hot water heating by using a separate control device that can ensure that the water used in underfloor heating is at about 45°C rather than the 80°C needed by normal radiators. Each method of heating has its relative benefits and disadvantages. Underfloor heating keeps walls free of radiators, but is not compatible with thick carpets. A pane of glass conducts heat easily, so windows with single panes can lose 10 to 20 times as much heat as the same area of wall. A house with single pane windows might lose a quarter of all the heat generated through its windows. Reducing the heat lost by windows is thus a significant issue. Most solutions to reduce heat loss also provide better sound insulation. The simplest method to reduce heat loss through windows is to provide another layer of insulation, for example by using curtains. Closing curtains at night makes a significant difference provided they are of reasonably thick material. Blinds, however, make relatively little difference. 
Double glazing, which adds another pane of glass with a gap between the two panes, is a much more expensive solution. Double glazing can halve the heat loss through the glass. Part of the benefit arises because the inner pane has still air beside it, which removes heat more slowly than the outer pane which is subject to wind chill. Adding a third pane (which is done in Scandinavia) reduces the heat loss still further. Some additional insulation can be provided by filling the gap between the panes with an inert gas, typically argon. A suitable coating on the outside of the inner pane also improves insulation. An example is Pilkington K Glass™. The coating reduces the emission of heat from the house by reflecting it back into the house. Such a coating in double glazing can achieve the same level of insulation as triple glazing. Window frames are also important to consider. The heat conducted by the frame depends on its width, depth, and the material used. Softwood is the best insulator, followed by hardwood and then PVC. All these provide reasonable insulation. A metal such as aluminium (or formerly galvanised steel) is sometimes used, as this provides durability and a narrower frame. However, metals are very good conductors of heat, and if a metal frame is to be fitted it is important that it incorporates an insulating layer to limit heat loss. Secondary glazing is a less expensive alternative to fitting double glazing on an existing property. It is often the only option for listed buildings where the appearance must be preserved. In this case a second window is installed inside the existing window. The energy benefit can be similar to fitting double glazing. One supplier is Protech Limited (www.secondaryglazing.com). Limiting heat gain is the other side of the window story. Large windows facing the sun on a summer day can overheat the room. Heat gain can be reduced by reflecting the sunlight using light coloured curtains or blinds, or by the use of shutters. It can also be reduced by a suitable coating. A very thin film of gold is sometimes used on office windows. Refrigerators, freezers and fridge-freezers 
These are typically the most energy-intensive appliances in the home. Recent models are much more efficient than the ones that were available even a few years ago, but there are still big differences. Look for models rated A++. The difference in energy consumption between fridge-freezer models could be worth up to £50 a year. Energy costs of freezers and refrigerators can also be reduced by waiting for hot food to cool before placing it in the freezer, by checking freezer seals regularly, and by keeping the freezer defrosted (if it is not a self-defrosting model) since a thick layer of ice reduces efficiency. Refrigeration generates heat, and it is very important to have sufficient ventilation, especially to the coils behind the fridge or freezer. If they are closed in, too close to a wall, or even covered in dust and cobwebs, the air cannot circulate and the fridge or freezer has to work much harder to keep its contents cold. This can waste a very large amount of energy. Keeping a fridge or freezer in a very warm room or very close to a cooker also wastes energy, and if the temperature goes much above 30°C it will not work properly. Freezers are often put into places such as garages, but they also do not work in very cold conditions, below 5–10°C. Models vary in the range of temperatures they can handle, so consult the manufacturer's specifications. 
Choose low-energy appliances when replacing appliances. Look for the energy-saving recommended logo when buying new electrical appliances, and compare energy consumption ratings on the labels. Do not run washing machines and dishwashers until there is a full load. Use low-temperature programmes in washing machines (30°C) and dishwashers (50°C, or lower if available). Dry clothes outdoors instead of using a drier whenever the weather permits. Most homes now have a wide variety of electronic devices and gadgets that each consume small amounts of electricity when they are on "standby", and often when they are switched off. These small amounts add up because there are probably more of them than you realise, and they are on all the time. There is more information, indicating which items are most likely to be the most costly, here. 
Switch off TVs, set-top boxes, and video recorders at the socket (not just on the box) whenever possible. Switch off computers, screens, and all connected devices at the socket when not being used for any length of time. For short periods put the computer to sleep. Disconnect any devices that are not being used regularly, or turn them off at the socket. External power supplies should be switched off at the socket or unplugged. (These are the "bricks" built into mains plugs, or the small boxes in the mains lead). Chargers should be switched off at the socket or unplugged when device is fully charged or they are not in use. The main options that might be considered for domestic energy generation with less use of fossil fuels are: 
These are discussed on our domestic energy generation page – it describes what is involved for each of these, their pros and cons, and the schemes for making them more attractive financially: the Feed-In Tariff for electricity generation, and the Renewable Heat Incentive for hot water and heating. |
