Power saving light bulbs: How much can you actually save

I know I like to bang on about power saving light bulbs, but it's for some very good reasons. For a start they can save you a fair amount of money, as this post will eventually point out. Secondly because you're using less electricity, you're therefore doing that little bit extra to help the environment.

While I have my concerns about the environment, most of my motivation for such things as energy saving and recycling are driven by the fact that in some way they are likely to be able to save me money or help make me self sufficient. It seems strange in some ways that nearly all the things you can do to make yourself self sufficient also seem to have some positive impact on the environment.

Self sufficiency will be another article later, so back to the light bulbs.

Lets see roughly how much money you could save a year if you changed to power saving light bulbs. After looking around the Internet it turns out that on average in the UK we use lighting in the home for around 1600 hours. This works out at about 4.5 hours a day. Now most homes will have a single room lit with either one or two bulbs for this amount of time along with several other lights on in other rooms as people more round the house.

For our example I'll do the calculations based on a living room with a single bulb lighting it for 4.5 hours a day 365 days a year. The first set of calculations will be based on a 60 watt non power saving light bulb, while the second example will be based on an 11 watt power saving bulb that gives out the equivalent amount of light as the 60 watt.

A 60 watt bulb uses 0.06kw/h of electricity for every hour it is on. So in this case in a year it will typically use 96kw/h. Now as we all know electricity prices have been rising lately so I'll take a rough average price for a kw/h of electricity at current prices, which is about 13 pence. So to run the light bulb for a year would cost £12.48

A 11 watt power saving bulb uses 0.011kw/h of electricity for every hour it is on. In a year it would use 17.6kw/h. Using the same electricity price of 13 pence per kw/h the power saving light bulb would cost £2.29 to run.

So initially we can say that in a year we would save roughly £10.19 or about 82%. However obviously we also have to take into account the bulb it self. A normal bulb would probably have to be replaced at least twice in a year period working on average bulb lifetimes, where as the power saving bulb would still only be around a third of the way into its life time. If we say that the power saving light bulb cost around £5 (I'm being conservative here, the last two bulbs I bought cost about £2 each) and the normal bulb costs around 60 pence a bulb then we still end up with a saving of roughly £6.40 a year.

Doesn't really sound much until you think that most house holds will have 2-3 bulbs running all at the same time. Also when you take into account that most people use 100 watt bulbs the savings really start to stack up.

If you replaced three 100 watt bulbs with three 11 watt power saving bulbs, that even though they provide the equivalent light of a 60 watt are still sufficient for the job. Over a typical year you could save approximately £40.50 which takes into account buying the power saving bulbs in the first place. It may not seem a lot until you think that in the average two bedroom house in the UK most people are paying £20 - £25 a month on electricity. Changing to power saving light bulbs could effectively get you two months worth of free electricity.

Obviously these are just worked examples and can't be exactly accurate, but even if you take a certain degree of inaccuracy into account it's still plain to see that simply changing to power saving light bulbs could save you a lot of money.