Green or not? Buying energy-efficient PCs

PC vendors are continually bombarding us with their new green credentials. They say our old PCs are energy gluttons and deserve consigning to the scrap heap of history. To save the earth, no less, we need to replace these inefficient white elephants with sparkly new PCs and monitors that use much less power and fewer rare and harmful chemicals.

There are plenty of online calculators that can back up this premise, demonstrating the fast Return On Investment (ROI) of replacing computing's 4x4s with its version of a Toyota Prius. But how much of this is marketing hokum and does it really take into account the carbon emissions through the whole of a PC's lifetime? For instance, a PC consumes more than ten times its own weight in fossil fuels during manufacture -- is this a consideration when people look at the energy efficiency of their new machines? Does the energy plate rating on the back of a PC really reflect the energy it is typically going to use?

To answer these questions and many more, we asked IT industry experts to justify their position. Should we accelerate the replacement cycle of energy-inefficient PCs and monitors, or do the opposite, and lengthen their lifetime?

Jeff Knowlton, SMB Marketing director at Dell UK: Accelerate and replace
When it comes to assessing and optimising energy use, there are a number of reasons why replacing old IT equipment makes more sense than sweating existing assets. For a start, newer technologies are designed to be more energy efficient than older ones. For example, LCD monitors use on average 50 to 70 per cent less energy in on-mode than conventional Cathode Ray Tube (CRT) monitors. At eight working hours a day, the energy saving of choosing an LCD over an equal size CRT could typically be well over 100kWh/year.

Other benefits of newer equipment include space-saving form factors and lower maintenance requirements. What's more, by choosing resale or donation options when it comes to disposal, organisations may even recover some value from old equipment.

Often the main reason a business chooses to hold onto existing infrastructure is hesitation at incurring the cost of new IT purchases and the effort involved in migrating from an old system to a new one. While purchase price can be a sticking point for many budget-conscious businesses, and migration can certainly be challenging, organisations which take a Total Cost of Ownership (TCO) approach to investment may discover that broader benefits such as reduced operating costs, improved performance and lower maintenance costs over the lifecycle of newer products can justify the initial investment.

That said, if replacing systems is not an immediately viable option for budget-conscious businesses, technologies such as virtualisation can extend the life of existing systems by unlocking hidden capacities and enabling some power efficiencies. However, once these advantages have been fully exploited, replacement is likely to be the only way forward.

Kate Craig-Wood, MD of Memset: Sweat the desktops, but replace the servers
Materials, manufacture and distribution of an average PC uses between 750kWh for the most modern 'green' PCs, and 1,300kWh for machines a few years old; and you have to add on about 300kWh for an LCD screen (500kWh for a CRT screen). They use about 100w when powered up and three watts when in hibernate mode. If we assume that the PC is on for eight hours per day, five days per week, and is hibernating overnight, we get 200kWh/year 'on' usage and 20kWh/year 'standby' usage.

So, a three-to-four-year-old PC probably used 1,200kWh to make and uses 220kWh/year to run, whereas a modern super-green PC might use 1,000kWh to make and burn 150kWh/year. Financially, you will save about £7 per year by switching to a green PC. Therefore it makes neither financial nor environmental sense to swap out old PCs before about six years.

The same sums applied to servers on 24/7 are quite different though. An average £1,000 rack-mount server bought three-to-four years ago probably cost about 1,500kWh to make and uses 120w at moderate load, which yearly is 1,050kWh -- or at least 1,500kWh when data-centre cooling is taken into account. The latest equivalent 'green' servers use as little as 80w, so swapping to energy-efficient servers will save 400kWh/year in electricity and get you two-to-four times more performance.

With good use of virtualisation to consolidate existing applications onto a smaller number of machines, it makes clear environmental and economic sense to replace servers after two-to-three years. As for the old servers and PCs, why not donate them to Africa via Computer Aid International, where our 'outdated' hardware is much needed and will be put to good and efficient use (only on when needed)?

What we think
There's definitely a case for replacing CRTs with LCDs. Costs have fallen dramatically and they also consume much less power. As for the boxes, we are firmly in the camp of sweating the assets. The principle driver for upgrading hardware is usually software, so it's pretty obvious -- by saving money not upgrading software you save money not having to upgrade hardware. Software that was fit-for-purpose in 2005 should still be fit-for-purpose. If you do upgrade software, often adding some more RAM will do the trick.

Hardware does fail though, particularly if you buy from budget PC brands that don't always source the most resilient components. If you do experience failure it's most likely to be the hard drive, power supply or maybe the CPU fan. All of these are relatively inexpensive to replace -- certainly much cheaper than that throwing the whole box away and starting again.

If you must upgrade -- and we can't persuade you otherwise -- then don't chuck the old PCs and monitors into bulk waste. Ensure that the WEEE directive is adhered to and give them to a charity or someone who could make use of them. Computer Aid International refurbs machines for Africa, or look for local recycling organisations. Defunct kit can at least be broken up carefully, preventing toxic chemicals from leaking into the groundwater.

What do you think? Are environmental responsibility and financial probity working together for once? Would you accelerate and replace or keep patching up the old box for another couple of years?