Watching someone's grandmother drive the speed limit in the right-hand lane in front of you can be a true test of patience when you're running late. You should know, however, that Grandma is getting excellent fuel economy. Aggressive driving — speeding, rapid acceleration, hard braking — wastes gas and can lower your MPG by up to 1/3.
Always wash full loads of clothes. Washing two half-loads of clothes uses twice as much energy (and water) as washing one full load of clothes.
With very few exceptions, you can always get your clothes clean in cold water. About 90% of the energy cost in washing clothes is in heating the water for hot-water loads. Here's a real tip, though: always use laundry detergent formulated for cold water to get your clothes really clean.
Use low-flow shower heads in your showers! Not only will this save you money on your water bill, but you will also use less hot water, which saves you money on your gas bill.
For some reason I don't quite understand, we managed to use 32 therms of natural gas last month. The heat was off, of course; June in Atlanta gets hot! How hot, you ask? Well, there were 444 cooling degree days last month, which is a way to measure how hot or cold it has been.
The number of degree days for any day, week, month, or year is found by calculating by averaging the low and high temperatures for that period of time and then comparing that average to a base value of 65°F. For example, if the average for a day is 55°, then there is a 10° difference between 55° and 65° and that day has 10 heating degree days (HDD). On the other hand, if the weather has been warmer, and the average temperature is 75°F, then that day has 10 cooling degree days (CDD). The number of degree days for a period of time is calculated by adding up all of the degree days for each day during that time.
This is an excellent way to evaluate what part of your energy usage comes from heating or cooling your home. Of course, HDD and CDD are location-specific; all of my values are for Atlanta, GA and come from the National Weather Service.
Our cost for electricity is up one-and-a-half cents per kilowatt-hour, but this is normal when summer starts. And our water usage is down about 25% since I adjusted the sprinklers last month to water three days a week instead of four. Otherwise, it was a fairly normal utility bill.
June 2007 Data
Electricity, in kWh
Cost / Unit
Gas, in Therms
Cost / Unit
Water, in CCF
Cost / Unit
Don't use the extra rinse cycle many newer washing machines offer to get extra soap out of the clothes. If you have this problem, don't rinse the clothes again — use less soap!
Apply sun-control or other reflective films on south-facing windows to reduce solar gain. Have you ever noticed just how nice the sun feels in the winter when it comes streaming in that south-facing window in your house? My cats curled up in the sun whenever they could because it was nice and warm. That same warm sun comes streaming in during the summer as well, and is costing you a fortune with your air conditioning.