Monday, February 16, 2009

Wot What Watt

one of those meter gadget thingiesRuscombe Green posts on Household electricity monitors. Some local authorities have bought a stash of these and hire them out to residents just like library books. They have two parts. A base which is connected to the out wires of your electricity meter and a remote which shows the amount of electricity being used. So, you wander around the house switching things on and off and you can tell which appliances are the guzzlers. But why do you need a gadget? What is the fascination of modern society with gadgets? What did we do before we had gadgets? I’ll tell you. We looked at the rating plate on the appliance of science.

Electricity is charged by the unit. One unit = a Kilowatt hour. So, if you switch on a 1 Kilowatt hot plate and leave it on for an hour you will have used one unit. If you switch on ten 100 Watt light bulbs and leave them on for an hour you will have used one unit.

If you are reading this you must be using a computer, so can we assume that you can also handle a simple spreadsheet? Yes, I thought you could. Here’s what you do. You go round the house and make a list of all the electrical items and take a note of their rating – that’s the wattage. 100 Watts = 0.1 Kilowatts. Don’t forget the shed, there will probably be power tools or a lawn mower in there. Don’t forget the kitchen cupboards where there may be a rarely used food mixer lurking. If you don’t want to pull out the washing machine to find the rating plate the wattage is usually recorded in the user handbook.


Now, for each appliance you need to estimate how much it is used over the course of a year. So, if it takes approximately 30 minutes to cut the grass and you cut the grass on average 12 times a year you will get 6 hours. Plug this into your spreadsheet. And then multiply the usage in hours by the wattage in Kilowatts. You now know how much electricity that appliance uses. Add them all up and, if your usage estimates are reasonably accurate you should come to a yearly total that is within a few percentage points of your actual annual usage.


Now you can look at each budget line and see where all the electricity is going and where you can make savings, and trade offs according to your own lifestyle and priorities. You may well have leccy guzzlers but if you don’t use them much it may not be worth replacing them with more energy efficient models. On the other hand if you have lots of low wattage items that are used a lot, you may well consider taking some action. You may even find examples like the 100 watt lightbulb you leave on in the porch uses more electricity during the course of a year than your 5 Kilowatt oven simply because you prefer to use a wok and only use the oven when the kids have got the time to visit for dinner. This is what your gadget won’t tell you and it really is the important bit. So much for gadgets.

When I did this some years back I discovered that around 20% of my electricity usage was on incandescent lighting. I changed to energy saver bulbs and that figure is now down to about 9%. I have made other changes too. Flat screen monitors and TVs for example are much more energy efficient than their Cathode Ray Tube predecessors. Don’t forget now, when you are in the shop look for the rating plate.


Sermon over!
May the Energy Gods be with you.

1 comment:

  1. Hello Barkingside 21 - the debate on the use of energy monitors comes at a good time!

    I'm currently co-ordinating a Scrutiny Committee Working Group which is looking at household emissions - and the Council's role in reducing them. The Working Group has considered various good practice - including the loan through libraries of the energy monitors.

    Before the Working Group reports to the Environment and Highways Scrutiny Committee, and thereafter Cabinet, I have been asked to undertake a short trial with the use of a couple of monitors to assess whether people find these easy to use, to consider their potential effect in raising awareness, and if the loan of monitors through libraries would generally a worthwhile project to support.

    The monitors are currently on order - would anyone from Barkingside 21 care to trial one for a week or so, in order to assist research?! (you never know - you could save some money on reduced energy bills as well!)

    Many thanks

    Paul Umfreville
    Scrutiny Research and Development Co-ordinator
    London Borough of Redbridge
    paul.umfreville@redbridge.gov.uk

    ReplyDelete