The ENERGY STAR programme primarily deals with energy consumption of office equipment during product life. This automatically raises the question of how important the direct energy consumption during product life would be in regard to other environmental aspects.
In the last decade several environmental case studies of PCs and monitors have been carried out. Few if any are up-to-date and comprehensive. Nonetheless, some indicative answers can be found.
Most studies, from the 1998 Ecolabel study to the ongoing 2003 study by the TU Berlin/Frauenhofer IZM (source: c't 2003/21, pp. 153), report that -for an office PC- primary energy consumption during use is more than 3 to 4 times higher than the primary energy needed for manufacturing and materials production, whilst the energy costs/credits of waste disposal and recycling are negligible (<15% of production energy). Mind you, this is the result for a typical office PC, used 8 hours per day (incl. Standby) over 260 days. But even for a modestly and efficiently used average home PC, the total energy consumed during its 6 year life (EU average) is more than double the energy used for its production.
A laptop is typically 50 to 80% more energy efficient than a desktop, but it is also much lighter (1.1 to 2 kg compared to >8 kg for a desktop). Therefore, here also, the energy consumption during its product-life is expected to be the dominant factor.
The average product-life of a PC in the European Community is about 6 years (c't 2003/21, pp. 149). There is a small market of second-hand PCs, where the average age of the models on offer is almost 3 years. Because new CPUs tend to consume more energy than old CPUs (compare a 486-processor PC of 60W with a Pentium-4 PC of 120 W in on mode) it is generally advisable from the environmental point of view to extend product life as long as possible, as long as you don't use them as servers (see Home Networks).
Regarding the 'other environmental aspects' besides energy, there are some developments linked to current legislation: The phase-out of certain flame-retardants, the introduction of lead-free solders, etc.. Also there are ongoing discussions on PVC in cables, mercury in display-lamps, electromagnetic radiation, noise, etc.. It is difficult to measure the impact of these issues against the energy and CO2 issue. But what can be said is that these 'other environmental aspects' are usually outside the sphere of influence of the buyers/consumers. In as much as the debates are conclusive, the result is normally dealt with in mandatory legislation (WEEE, RoHS, etc.). What can also be said is that the PC is currently not seen as a product where these 'other environmental aspects' are predominant: The recent Ecolabel discussion paper on computer equipment identifies energy consumption during use -together with noise- as the prime area for improvement.
Ecoprofiles for imaging equipment are totally different. Not only is this equipment idle for relatively much longer periods which is why low standby use and power management are relatively more important than with computer equipment but also the energy needed to produce paper and toner are much more important than the energy used by the equipment. For single-sided printing/copying on a midrange office copier the "toner power" is 3 times higher than the electricity used by the machine. The "paper power" is 50 times higher!
For this reason duplexing, i.e. double-sided printing/copying, is the best energy saving option. After that, the use of recycled paper is another option. Taking a look at the toner consumption of your machine is a third alternative and finally the standby-power and the power management of your PC are other means. The electricity in 'on' mode is relatively less important, unless we are talking about professional, high-volume copiers/printers. More information on the energy use of equipment can be found in Aebischer et al.