Introduction

Have you ever thought about how much it cost to run your PC -- the one you're using to read this article? What does it cost to play games, surf the Internet, or download files? It all costs money -- money that you, your parents, or whoever is in charge of the monthly electricity will have to pay. Those of you in charge of paying this bill will surely be interested in keeping costs down, which is why you might want to pay a little more attention to what sort of hardware you are using in your computer.

Many users -- especially computer enthusiasts -- put together a new PC that can easily handle any task, without much thought for power efficiency. If you intend to use the computer primarily for gaming, buying a high-end processor and graphics card makes sense. Likewise, if you intend to do complex three animations or movie encoding, you'll probably want to have as much processor power as possible. If all you're going to do is watch movies, run Microsoft Office, and surf the Internet, you're not going to put a big load on any of the components. In that case, your PC will typically be idle and waiting for user input, while any high-power components will still go merrily along sucking down extra power.

We recently looked at the topic of power consumption for each component in the PC. Of course the numbers were merely a rough estimate for our specific setup, programs, and tasks, so that article could serve as a baseline for the amount of power your system might require. We also discussed how power requirements affect the type of power supply that you will want to purchase. In this article, we want to focus more specifically on the costs of running a computer (not counting anything like broken components and upgrades). We look at electricity prices in the US and Europe to calculate how much various types of PCs actually cost to run. Perhaps you're one of those people with multiple systems -- one for gaming, one for office work, maybe one or two for the kids, and perhaps a few extras running distributed computing tasks 24/7. We will look at several different workloads to see how much various types of systems actually end up costing on a hourly, daily, and yearly basis.

KWh prices in the U.S and EU

When we started researching prices of electricity (measured in kilowatts hours/kWh) for the different countries, we were surprised by the huge differences in price. In the US prices range from $0.05 to $0.21, according to the Energy Information Administration -- the average price is $0.089 per kWh. European prices are different for each country, so we will just take Germany as an example. Prices there are high relative to the US but about average for Europe. In 2008, Germany has an average of 17 to 22 Cents (€) -- about $0.22 to $0.29 USD! That's anywhere from 1.5 to 6 times as expensive in the old world depending on where you live; obviously, areas where costs are higher will probably be more interested in PC power consumption, but that is a separate issue from what we are looking at today.