These methods of reducing electricity usage cost nothing to implement.
An obvious way to save money, but many appliances are left on 24 hours a day. Even in standby mode, equipment still uses electricity. Typical examples include:
The main culprit here has to be plug in air fresheners. These consist of a small unit with a moulded plug. Inside is a small electric heater which warms a container of fragrance.
A typical plug-in air freshener uses 4 watts. Not very much, but left on permanently, this will use 35 units of electricity per year. Not to mention the expensive refills, and that houses with these devices tend to have one in each room.
5 of these in a house with electricity at 15p per unit, and your electricity bill has increased by over £25 every year.
Probably the most wasteful electrical appliance ever created, these heat air inside a drum and then blow most of the heated air straight outside through a vent. During this process, a small amount of laundry might become slighly drier.
Dry your washing outside whenever possible. Yes, it rains a lot, but check the weather forecast - if it is going to rain today, do the laundry tomorrow instead.
Most items can be washed at 40C or 30C.
It is useful to sometimes do a 60C wash to remove any resides from the washing machine.
There are no items which will benefit from washing at 90C. Modern washing powders will not work effectively at such high temperatures. Biological washing powder contains enzymes to help break down dirt, and high temperatures will destroy these enzymes.
Wash anything with synthetic fibres at 90C and it will be destroyed.
If you are concerned about bacteria in the wash at 30C, two capfuls of Dettol® liquid in the final rinse will solve the problem.
Remove the large amounts of dust from the back. Heat is removed from inside the fridge and ends up in the black radiator at the back. If the heat cannot leave the radiator, the fridge motor will operate more often and use more electricity.
For similar reasons, fridges and freezers need adequate ventilation. Putting a fridge into a sealed cupboard will just increase the amount of electricity used, and probably shorten the life of the fridge as well.
A number of people have a computer on 24/7, with the main function of it to store files for other computers in the home. Nothing wrong with sharing files, but leaving a computer switched on 24/7 is a huge additional cost.
Even at 100 watts (very low for a PC), this is 876 units of electricity every year. At 15p per unit, this is over £130.
In reality, the costs will be even higher, as many computers use more than 100W, and there is always additional equipment such as modems and routers.
Switching the PC off when not required could easily save half of that, and probably a lot more.
If you are using a home PC to host a website - don't. For one thing, when your power fails, so does your website. Or when your computer overheats, or the modem goes wrong, or a rat chews the phone wire outside, or vandals pour petrol into the street cabinet, or any one of hundreds of other problems occurs.
Second, there are hundreds of companies providing reliable, secure hosting for a lot less per year than the electricity costs for your home PC.