I was in a sandwich shop the other day and noticed a sticker on the door bragging that the chain had replaced one incandescent bulb in each of their 20,000-plus stores with a compact fluorescent bulb (CFL). Good for them, they are now green!

Next step? They should replace two and offer customers a coupon for doing the same.

You see, being green is not about making one change; it should be about invoking change for the better.

Solar, wind, carbon offsets — all large scale changes and all a bit confusing. Change a light bulb, conserve water, recycle paper, aluminum or plastic, and turn your a/c up one degree or your heat down one degree —all very easy to do. Small scale? Not when you consider there are four million people living in the Houston area.

These simple steps we made at home are saving us money every month:

1. We changed our incandescent bulbs to CFLs. CFLs are much improved and the price has come down dramatically. One CFL bulb can last three to five years; we would pay twice that replacing each incandescent once or twice a year.

2. Thermostat up in the summer, thermostat down in the winter.

3. We turn off the TV and cable box at night or when we are not going to be home.

4. We switched to an energy provider with wind and hydroelectric energy choices. This took 10 minutes to do and our electric costs came down right away.

5. No more plastic water bottles. Did I mention 1.5 million barrels of oil are used in the United States alone to make those plastic water bottles? And more than 20 billion plastic bottles end up in landfills or incinerators every year.

Two more quick thoughts:

• No more plastic bags at the grocery store. Fabric, cloth, reusable bags all work fine. America uses 90 billion plastic bags a year. Most end up in landfills and incinerators. Rwanda, Germany, Belgium, Botswana, Sweden, South Africa and Uganda have banned them, China has restrictions on their use, and a few cities in the United States are following suit.
• Styrofoam containers and cups. Really? You still use them? Toxic chemicals can leach out of them when heated and they do not break down in the environment for hundreds of years. Styrofoam cups and take-out containers are convenient but unnecessary with so many other products on the market. Normally take home restaurant leftovers? Bring a small plastic container from home.

Peter Riger is director of conservation and science at the Houston Zoo.