Friday, July 31, 2009

Air Conditioning or Windows Down?

A debate rages about (who would guess?) which uses less gas: rolling down your car windows or turning on your air conditioning. However, all 3 tests I could track to their sources showed that running the air conditioner almost always uses more gas than rolling the windows down. For example, Car and Driver did a test on a sedan (they don't say what model, but the photos are of a small sedan) in which running the a/c reduced fuel efficiency by 15% at 35 mph, whereas opening the windows decreased it by only 1.5%. At 75 mph, running the a/c decreased miles per gallon by 6.8% vs. 2% for windows, and results at 55 mph were in between (losses for a/c decrease at higher speeds because the engine is producing more power.)

Consumer Reports findings for a Camry were less dramatic: using a/c at 65 mph decreased the car's fuel efficiency by 1%, whereas rolling windows down at that speed had no measurable effect on fuel economy. A third study by the Society of Automotive Engineers shows that while the results are closer for a sedan, both the sedan and the SUV used more gas with the a/c on than with windows down at speeds of 30, 50, and 68 mph when the temperature was 86F. Bottom line: minimize your use of air conditioning, especially when you're tooling around town. Keep in mind, too, when you ride the bus or train, you can enjoy A/C guilt-free, and bicycling creates its own cooling!

Comment with your thoughts, and stay cool!

Friday, July 24, 2009

Simple Ways to Keep Cool

Here's a few basic things to do to keep cool, reduce your carbon output, and cut down on cooling costs this summer:
  • Open windows when it's cooler outside than inside.
  • Even more important: Shut windows when it's hotter outside than inside. I haven't seen this advice elsewhere, but it can keep your house substantially cooler. Once the temperature outside goes above the indoor temperature, open windows heat your house. Try closing them-it may surprise you how much cooler it stays.
Here's some more tips, courtesy of I've been doing some of these for years, and some of them were new to me:
  • Close drapes and shades when sun is shining in, especially on east and west sides of house. Open them when it's cooler outside than in. (It helps if you're a bit obsessive, like me.)
  • Use ceiling and portable fans rather than air conditioning as much as possible. The breeze can make you feel just as comfortable as lowering the temperature 6 degrees.
  • Plant shade trees to block the sun.
If you must use air conditioning, follow these tips:
  • In dry climates (like Santa Fe), use an evaporative (swamp) cooler rather than a conventional refrigerated air conditioner. Conventional A/C uses 4 times the electricity a swamp cooler uses, according to energy company PNM. Swamp coolers only work in fairly dry climates, though.
  • Keep the thermostat as high as possible, 78 F or above. Each degree you raise it saves 2% on your cooling bill. Your house won't cool down any faster by lowering the setting.
  • Minimize opening and shutting doors, which lets heat in.
  • If it's humid, use a dehumidifier. You'll be comfortable at much higher temperatures.
  • Install room air conditioners where they'll be shaded-- they'll work much better. Seal any gaps on the sides with foam insulation.
  • Close off vents in unoccupied rooms. You'll save 5-10% on your energy bill. Close doors to those rooms if possible.
Comment with your ideas, and stay cool!

Friday, July 17, 2009

Reduce Your Vacation Footprint

Since it's vacation time, here's a comparison of different modes of travel and their carbon footprints by, a non-profit think tank. SUV's with a solo driver produce the most CO2 per passenger per mile, followed by regular cars, airplanes, hybrid cars, cars with 3 riders, buses, and then trains, which produce the least CO2 per passenger mile except for walking or biking.

There's a lot of variability in the amount of fuel airplanes use, so use the World Wildlife Fund Travel Helper to decide what's the best way to get to your particular destination (even though it says Europe, it works for US destinations too). Then you can use a site like the Terrapass Calculator or Travelocity's Go Zero program to make a donation to a program that's reducing emissions. That way, you'll offset the emissions you produce with your travel. You can get to Terrapass and Go Zero at the very bottom of Carbonless Copy's home page. is another site that sells offsets.

Of course, a lot of people are staying home this summer, and that's the most carbon-conserving of all! Let me know how you're reducing your greenhouse gas emissions, and
Stay cool,

Friday, July 3, 2009

Tell Senate to Join House in Passing Climate Change Bill

On June 26, the US House of Representatives passed the historic American Clean Energy and Security Act, also known as Waxman-Markey (see my June 5 and April 10 posts). This is the first bill that a US Federal body has passed to curb greenhouse gases. In comparison, the European Union and its member governments have been committed to and achieving greenhouse gas reductions for about a decade. Let's celebrate the passage of this bill, though flawed, as a critical first step in achieving reductions in global warming!

Even more important, we need to urge the Senate to pass the bill, and we'll have to follow it through conference committee to ensure the strongest measure possible goes to President Obama, who strongly supports it. Click here to sign a petition on Al Gore's website to show Senate leaders you support the American Clean Energy and Security Act. Then post your thoughts and ideas for reducing our carbon footprint in a comment!

Stay cool,