My electricity supplier sent me a review document. In it they flagged a number of changes that could reduce my energy usage. Of these changes only one claimed to payback within 20 years. That change was to install compact fluorescent bulbs.

This article explains the benefits;

http://en.wikipedia.org/wiki/Compact_fluorescent_lamp

My electricity supplier thinks it will cost 100 GBP to switch my house to compact fluorescent bulbs, Wikipedia thinks £1.46 ($2.75) per bulb, the current shop price is £0.98 ($1.80) for an 11W bulb (to replace a 60W).

Wikipedia reckons $0.10 per KW hour, my electricity provider bills closer to $0.25. As a result the payback time is around 150 hours (not 500 hours). At three hours use a day that is a mere 7 weeks. At that price it is worth retiring the old bulbs (you can always use them in any lights with a dimmer switch, as the cheap compact fluorescent bulbs aren't suitable for dimmer switches). Also worth checking the form factor, as some of our light fitting don't have room for the cheapest of the compact fluorescents, but I'll look around next time I'm in B&Q.

I'm not naive enough to think changing lightbulbs will stop global warming. However it is a change backed by peoples own short term financial interests, where as many of the changes we are likely to have to make in the future may have much less immediate paybacks, and may rely much more on International co-ordination, and we know how easy that is to achieve.

Switching energy suppliers in the UK is now also dead easy, so perhaps I should have started this with "My former electricity supplier...".

http://www.uswitch.com/