When we talk about solutions to our energy problems a lot of us use the words 'efficiency' and 'conservation' interchangeably.  But let's take a closer look at how collapsing these two distinct words can be dangerous. 

Efficiency is a word created by engineers to quantify machine performance.  Efficiency is the ratio of useable energy developed by a machine compared to the amount of energy fed to that machine to achieve the desired result.  Example: if we feed 100 units of energy to a machine which uses it to produce 40 units of useable energy (or product), the machine's efficiency is 40%.

The benifits of an efficient machine only really come to light when a machine is turned on for long periods of time.  The longer it stays 'on' the more we 'save' in terms of energy and money compared to less efficient machines which are turned 'on' for the same length of time but produce less results.  So, as long as we're getting a high efficiency rating we can use it as much as we want right?  Say I buy a Hybrid car.  It's an efficient machine and the more I drive it the more I 'save' so no one would ever question just how much I drive my car.  But who's more environmentally responsible? Me and my Hybrid driving 90000 Km/year or someone with a less efficient car who consciously only drives 20000 Km/year?  Well, we can't be sure until we crunch the numbers but I think the point is clear.  Buying an energy efficient machine does not give us liscence to use it frivolously. 

Both efficiency and conservation are important, and to really make a dent in our energy demands we need to utilise both.  Unfortunately, high efficiency technologies are still an expensive option that we can't all afford.  Thankfully though, conservation is as free as it is priceless.  We all need to start exercising our conservation more, regardless of whether or not we can afford high efficiency machines.

So Turn off unused lights (even if you use compact fluorescents), don't drive needlessly (even if your driving a Hybrid), only run full washer loads (even if you just bought an energy efficient, side-loading washing machine).