ENERGY EFFICIENCY TIPS

Topic list  (composed of in-page links):

Considering cost

Choosing equipment

Preserving value

Reducing space heating costs

Reducing water heating costs

Reducing cooking related costs

Reducing lighting costs

Reducing refrigeration costs

Reducing dish washing costs

Reducing cooling costs

Reducing drying and ventilation costs

Reducing other electrical costs

 

Considering cost

  • Keep running costs in mind when planning purchases. Running costs of electrically powered (and gas fuelled devices) can be calculated as follows:
    Take the number of watts of input power used by a device in question; multiply by the time (in hours) that the device will typically be used each day;
    multiply by 365 to give an estimate of the device's usage time in a year;
    divide by 1000 to give an estimate of the number of kilowatt hours used;
    multiply by the kilowatt hour or unit energy cost (stated on your bill) to give an estimate of the yearly running cost of the device.
    (UK unit costs in 2011 typically ranged from 12-15 pence depending on region and tariff for electricity and 4-5 pence for gas).

 

Choosing equipment

  • The results gained from your calculations will enable you to compare the savings that may be made by replacing an existing piece of equipment with the costs involved in making the replacement. Even in cases when energy efficiency is a prime concern, replacement will not always be the best option. Remember that part of the cost of the device will be spent on the energy required in its manufacture manufacture and transport. The cost of replacement should always be factored with the potential value of savings.
  • A clarification of the energy costs of devices may be gained through the use of wattmeters and similar devices. Types of meter that record power consumption over time may be especially useful in helping you decide when deciding when intermittently activating types of appliance need to be serviced or replaced.

 

Preserving value

  • When energy is used or gathered to produce a useful effect then it makes sense to make best use of the result.
  • Houses are not only heated by their dedicated heating systems. They also gain heat by such means as the operation of water heating systems, through cooking activities and even through the the simple "greenhouse effect" of light passing through glass. It doesn't matter how the heat is acquired. When its cold outside it all needs to be conserved.
  • Light, on the other hand, should be allowed to travel. It should be enabled to reach the places where it is most needed.

 

Reducing space heating costs

  • Review the insulation of your home - windows, wall cavities, lofts etc. Checks may need to be made that electrical cables are substantial enough to allow them to be covered in insulation without their becoming overly heated. Otherwise its advisable to cover loft floors with as much non-flammable insulative material as can be conveniently fitted in.
  • Fit full length curtains that fit snugly with the floor. Fitting a pelmet above will also help reduce air circulation when the curtains are drawn (which is best not left long after sundown).
  • There are still benefits to be gained in placing radiators beneath windows so as to counteract the down-draft effect that the windows continue to generate despite improvements to window insulation. Radiators beneath windows will obviously have greatest night time effect if a minimum of window cooled air is enabled to sink into a room while allowing the maximum radiator warmed air to remain in the living space. Overlaps between radiators and curtains should typically be avoided. One practice is to tuck curtains behind the radiators or onto window sills on cold nights.
  • Try not to place furniture in front of radiators especially if circulating air is prevented from being drawn in to the radiator's base by either the furniture itself or by all the stuff that gets packed beneath it.
  • Carefully hold a smoking combustible material (such as an incense stick) near the frames of exterior windows and doors and in other places that you think might be draughty. If the smoke moves then an air leak is likely. A thin shred of paper or string may also be used if a combustible smoking material is not available, though it may not work as well.
  • Replace old, leaky windows (especially single-pane glass) with newer double or triple pane, gas filled windows whenever it is cost effective to do so.
  • Protect exposed buildings from cold winds using windbreaks such as hedges, walls or even landscaping.
  • Turn your thermostat down. Reducing your room temperature by 1°C could cut your heating costs by up to 10 percent.
  • If you have a programmer, set your heating and hot water to come on only when required rather than all the time. Set your heating to go off perhaps 45 minutes before you leave the house, and come on again a similarly suitable time before you expect to return. Timings may depend on the individual rate at which your property cools down and warms up.
  • Consider which rooms you need to use in the winter and turn off the heating in the others.
  • If you have more space than you need, consider moving to a smaller property.

 

Reducing water heating costs

  • Hot water can, quite literally, act as heat down the drain.
  • Use low temperature settings in washing machines and use full loads where possible. One full load burns less energy than two half loads.
  • We invest large quantities of energy to bring water to the boil so, unless your kitchen is already got too hot, don't be too hasty in throwing pan warmed water down the sink. Heated water that is thrown out will only have a limited effect in turning your under-sink pipework into a radiator and a significant proportion of the heat will be wasted.
  • Try straining foods so as to allow the heated water to flow into another pans such as a pan that needs cleaning. Leave the filled pans on an unheated parts of your hob and cover them to prevent heat loss through evaporation.
  • Fill up your kettle or pan with just the amount that you need.
  • Use electric kettles or gas heated pans to warm water. Electric kettles are convenient and, if clear of limescale, heat water with great efficiency. Gas though is cheaper than electricity. If you wanted the water for a saucepan anyway or if your kitchen could do with the "wasted heat" of gas cookery then gas will have the advantage. The big problem with the hob though is it takes longer . . . . and you can forget about it. The only thing that's clear is that, given current costs, both options have well over twice the efficiency of heating water on an electric hob. (Calculations by William Steer)
  • Lightweight kettles are efficient water heating machines but, in hard water areas, may need a little care. Limescale will add additional mass to your kettle which will need to be heated each time its switched on. Worse the limescale also acts as an insulator between the thermally conductive element and the thermally convective water with the result that the element will be forced to far higher temperatures to do its job. Limescale balls have the disadvantage in that they also absorb your expensive, electricity generated heat. Limescale can be treated with acetic acid (as found in vinegar) or citric acid (as found in lemons) or with typically similar substances (used in commercial descaling products). Just remember to rinse the kettle out properly before your next brew.
  • Similar principles are reported to apply to washing machines and dishwashers and to other machines such as coffee makers in which water is heated.
  • Showers have a clear potential to use less water than baths dependent on the rate and duration of water flow used in the shower and on the content of water used in the bath. A normal shower may use 7 litres per minute, a power shower may use 12 litres per minute and filling a bath may require 80 litres (source: Waterwise). Your own comparisons may be easily made, for instance by temporarily plugging your shower.
  • Consider adjusting your water thermostat so that the temperature of the hot water alone will be comfortable for a bath or shower. In times of the year when you don't need heating, heat lost from your water pipes and hot water tank would be wasted. You may occasionally need to turn up the heat, for instance when getting ready for a long bath. By the time the bath has cooled down, water in your tank may have gained the heat necessary to warm it back up.
  • If you use a tank based heating system you can also save money in the summer by switching the system off between times when more highly heated water is needed.

 

Reducing cooking related costs

  • Turn off ovens, stoves etc. shortly before the end of required cooking times. An earlier build up of heat can then be used to finish the cooking process.
  • Give some thought to the heat output of your winter cooking. In some circumstances the heat generated from the cooking may be distributed around the house without the distribution of unwanted smells and this may allow you to turn the thermostat turned down while prepping your food.
  • Your cooker is probably built with about four hob burners, an oven and perhaps a grill as well. Unless your house can make good use of the heat, try not to use them all at once and take good advantage of foods that require less cooking through the summer months.
  • Use pans of a suitable size for your cooker rings and use smaller rings when possible to prevent heat loss.
  • Consider using pressure cookers, one pot cookery multi level steamers which use less energy.
  • Use a lid on pans where possible, so the contents heat up faster and require less energy.
  • Better still, if your crockery can take it, use dinner plates and serving dishes as the lids of veg pans.
  • As far as carbon efficiency is concerned, unless your electricity supply comes from a provider that specialises in only producing renewable energy, gas powered cookery will facilitate a lower carbon footprint than electric. (Most electricity companies do little more than to fulfil their renewables obligation and then produce the majority of their electricity through the inefficient burning of fossil fuels).
  • Microwaves are best used for cooking non dried types of food.
  • They also have reasonable ability in heating foods that contain liquid water or other non-frozen substances, such as fats, that contain dipole molecules. Microwaves work by jiggling the dipole materials. This explains why microwaves are not so relatively good at defrosting deeply frozen foods and why, once defrosting begins, some content may get relatively hot while other content remains firmly frozen.
  • If you really have to use a microwave to warm up rigid objects such as crockery (obviously not recommended) then give them a light coating of water first. The water will absorb the microwaves much more readily than the china.
  • When boiling water, once you've brought it up to boiling point, Reducing the heat on the stove to a moderate boil or even to simmering. A high boil will do little more than shake your ingredients around some more while simultaneously filling your house with steam. Cooking on gas will add even more humidity to your house while removing a proportion of the oxygen. The hydrogen in the gas reacts with oxygen to form h2o.

 

Reducing lighting costs

  • Take advantage of sunlight and leave lights off during the day. If possible, adjust your daily routine to align your waking hours with sunlit hours.
  • LED lights have the advantages of excellent efficiency, extremely long service and, as a final far distant consideration, easy disposal. Their only down side is that, at present, they have a relatively high cost (both monetarily and in the energy required in their production) and yet long term use will make them a good investment.
  • Compact fluorescent lights last 8-15 times longer than standard light bulbs while using 20 to 33 percent of the power and yet they contain mercury and phosphorus which brings complications to their disposal. Note: most CFLs and other fluorescent bulbs are not designed for use with a dimmer.
  • Try to limit the extent to which you put lights in forms of shade. In cases where "light shades" are needed choose those that merely diffuse light and have less potential to gather dust.
  • Dust light shades and light bulbs occasionally (with the power off) to increase light levels.
  • Give yourself just enough light. Choose light fixtures that fit an appropriate number of bulbs and choose bulbs with an appropriate level of wattage. If necessary remove some of the bulbs in existing fixtures

 

Reducing dish washing costs

  • Modern dishwashers use less energy and water than washing up by hand. Dishwashers manufactured since 1994 may typically use seven to ten gallons of water per cycle, while older machines use eight to fifteen gallons. The water may now be heated in the dishwasher itself so as to avoid loss of heat in transit and they may only as much water as they need. Older, less-efficient machines may best be saved for large events when they may be most needed.

 

Reducing refrigeration costs

  • Fridges, freezers and fridge-freezers share one thing in common. They run 365 days a year, 24 hours a day consuming electricity whenever their thermostats demand. The disposal of unwanted fridges can also be an expensive hassle and, as such, it's worth paying attention to the electricity consumption, longevity, serviceability and installation plan of fridges when you buy.
  • If you have to have a fridge installed in a built-in unit make sure that ample ventilation can still get to its radiator.
  • Placing fridges and freezers in cool rooms (and out of close contact with heat generating appliances such as an oven, boiler dishwasher and some washing machines) will help them work efficiently. If the fridge is going in a room built with just one thickness of brickwork (a garage or shed for example) try to place the fridge with its back to a wall that won't be overly affected by the summertime sun.
  • In total fridges and freezers generate more heat than they extract - so, when Chrismas has been and gone and depending on your later needs for refrigeration, consider giving a second appliance a summer break. If you can do without that summertime cool box then you will be simultaneously freed from its summertime radiator.
  • Don't leave fridge doors open and avoid putting hot or warm food straight in to fridges and freezers.
  • Leave your freezer sufficiently stocked so that less cold air will fall out when opened but not so packed that it will take long prolonged periods with the door open to squeeze items in.
  • If you will need to regularly access your frozen items (and if you have the space) consider getting a chest freezer. The door on the top makes it difficult for cold air to fall out when its opened.
  • Do try to use your fridge as a place to let frozen foods gradually defrost. The absorption of heat through the thawing process will save your fridge from a lot of effort.
  • In other situations, when you need to defrost foods more quickly, try to do it in ways that won't unnecessarily reduce the heat of your living space. Use an unheated garage if available or a bowl of water. A garage maybe half way to being outside and moderate quantities of water that are chilled through the thawing process can easily flow down your sink and out of your life. As long as the final temperature of the water is lower than the temperature of water coming in, a personal energy saving will have been made.
  • Try to defrost freezers when they have accumulated 4-6 mm thickness of ice.
  • If ice tends to develop by the door of the fridge check potential blockages to fridge closure and the door seals. Exchanging door seals can be expensive but it will be cheaper than exchanging a fridge.

 

Reducing cooling costs

  • In the same way in which your winter heating bills may be cut by 10% by turning your thermostat down by just 1°C, a similar cut can be made to air-con cooling costs by setting the thermostat to a slightly higher target temperature.
  • It may also be considerate to people who come in from comparatively highly heated environments outside and into an air conditioned space not to set air conditioning thermostats to too low a level. Thermostats should not be set at low levels just for the sake of it or to make it clear to the world that an air conditioning facility has been provided. Air conditioning may be best used to ease discomfort and not to cause it.
  • And even if you have air conditioning keep doing the kinds of things you would do to keep cool if you didn't. Choose foods that don't need cooking. As long as they wont pose a fire risk, grow plants in and around your home. Photosynthetic process has the endearing quality of turning potentially heat generating light into sugar. The plants can suck out the heat while perhaps providing shade and they may even produce food while at it.
  • Portable air-conditioners typically work by enabling the evaporation of water. A similar effect can be achieved by filling sinks with a little water and hanging damp sheets on airers.

 

Reducing drying and ventilation costs

  • The evaporation of water requires a considerable input of heat. The evaporation of a single cubic centimetre of water will require an energy equivalent to a 1.74°C temperature drop in a whole cubic metre of air. With this in mind we can consider that a 4.5 kg load of spun laundry will typically contain about 1.5 litres (or 1,500 cm3) of water and realise that a lot of energy would be absorbed in drying this load.
    Tumbler dryers reclaim this absorbed heat through their concurrent use of condensers and yet, weather permitting, it's still generally best to let laundry dry outside. Tumbler dryers may act as an expensive way of providing heat for your house and, as such, they are best kept for rainy days when nature can't dry your clothes for free.
  • The BBC have both five day and more detailed 24 hour weather forecasts for Lewes with inset forecast videos while the Met Office offers various five day weather maps for the South East that separately cover " target="_blank">weather and temperature. Localised forecasts are currently provided for Newhaven, Brighton, Uckfield and Gatwick.
  • When drying your clothes indoors, use a clothes rail instead of a radiator as this stops the heat from reaching the rest of the room.
  • Bathrooms are a major source of household humidity and yet heat recovery ventilation systems offer an initially expensive but potentially efficiently elegant solution to the problem. Mechanically sound products may achieve 84% heat recovery. Exhaust air flows out through a setup of thin air channels so as to allow the heat of the outgoing air to be gradually absorbed by the incoming air. (Similar units are also claimed to be usable in kitchens but this might require the fairly regular cleaning of their relatively small filters).
  • Wiping down a shower unit will allow your bathroom to dry more quickly both increasing the lifespan of your tiling and saving energy. A small to medium sized window cleaning squeegee can be used to efficiently remove most of the water.
  • A relatively efficient way of airing large areas of your house (relevant for properties that have been well protected against draughts and which have a lack of air brick ventilation) is to briefly open windows and doors prior to going out. The extra ventilation would still allow the temperature of the house to get closer to outside temperatures and yet it will still be cheaper than airing the house at times while trying to sustain its regular levels of warmth.

 

Reducing other electricity costs

  • Don't use standby. Appliances such as TVs, videos, music systems, computers and microwaves are best turned off when not in use both for security and to prevent the waste of the electricity that would otherwise continue to be used. Device chargers will typically need to be unplugged to stop power consumption once the device is charged.
  • Switch off lights when leaving rooms.
  • Consider the energy savings that can be made by LCD TVs and computer monitors as one factor to influence the timing of future upgrades.

 
© Lewes Electrical 01/09/11

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