Earth Day is Tuesday, but some are celebrating all week. Of course, every day should be Earth Day, considering all the challenges that our planet is facing, including climate change.

As technology users, there are things we can do to make a dent. Even very little things, when multiplied by millions of people, can have a big impact.

One thing we can do is reduce power consumption. Turn off your PC or make sure it goes into sleep mode when you're not using it. Don't use "screen saver" software that puts a moving image on your screen when it's not in use. You don't need them with modern LCD displays and they waste power. Have the screen simply go blank after a period of inactivity. Windows and Mac OS X have controls to maximize power saving.

When buying a PC, printer, appliances, heating and cooling equipment or just about anything else that uses power, look for Energy Star compliance as a basic minimum. For most homes, a programmable thermostat is an inexpensive and effective investment. The Environmental Protection Agency estimates that programmable thermostats can save about $180 per year in some climates. The EnergyStar.gov website has other recommendations, including sealing insulation leaks and using a space heater rather than heating an entire house. The website can help you find Energy Star certified products.

Beware of passive energy hogs. Those little plugs that charge our cellphones, for example, typically use some power when they're plugged in, even if they're not in use. Unplug them or plug them into a power strip that you can turn off. The Bussmann Chargesmart Universal Mobile Charger shuts off when the device it's charging no longer needs power, according to the company, but at about $20 on Amazon, it's a pretty expensive charger.

If you have a laser or ink jet printer, you can save plastic by recycling your cartridges (some office supply stores will give you a rebate for turning them in). You can also refill most ink jet cartridges, which helps the planet and your budget. There are do-it-yourself kits, but it can get kind of messy. You can have them refilled at Costco and many other stores.

Printers can waste a lot of paper, so don't print if you don't have to. I sometimes email documents to my cellphone or tablet so I can refer to them when I'm out of the house. When you do print, try using draft mode, which uses less ink. When shopping for a printer, look for one that automatically prints on both sides and chose printers that get a lot of pages per cartridge. Sometimes you have to pay a little more for them, but they can more than pay for themselves over time.

Even the font you use can affect energy and ink use. In 2010, the University of Wisconsin at Green Bay switched fonts from Arial to Century Gothic, which uses 30 percent less ink. But it also takes up more space, which can waste paper. The website Ecofont.com sells a $25 font for Windows that, according to the company, saves ink without using more paper. I tried it and noticed that the ink wasn't as dense on the page.

There are plenty of other ways to save energy. LED bulbs are even more energy efficient than compact fluorescent ones and they last longer. They're more expensive, but have come down in price lately, so consider them when replacing bulbs.

Telecommuting is a great way to save energy, as is having Web-based meetings instead of traveling. Google Hangouts, for example, allows you to have free video conferences with up to 10 people.

Reading books on electronic devices is certainly more efficient than buying printed books. You don't necessarily need a dedicated e-reader. There are Kindle apps for most tablets and smartphones. And I don't mind reading books even on a 4- or 5-inch smartphone screen. Having said that, there are still environmental concerns when it comes to online reading. Not only does your device need power, but so do the servers that store and deliver the material, which is why it's important to encourage Internet companies to install more efficient servers and use renewable energy to the extent possible.

And when thinking about buying electronic devices, consider that the manufacturing and recycling of equipment uses energy and resources and can produce waste. You should try to reuse, donate, sell or at least recycle any equipment you're retiring, and you also should think about whether you really need to replace that phone, tablet, printer, PC or other gadget.

Even those free phones you can get from your cellular company every two years are not completely free. Mother nature pays the price.

Contact Larry Magid at larry@larrymagid.com. Listen for his technology chats on KCBS-AM (740) weekdays at 3:50 p.m.