By Donella Meadows

–February 6, 1992–

One mature tree on the south side of your house provides as much summer cooling as five midsized air-conditioners.

A single open fireplace damper sends eight percent of your heating bill up the chimney.

The television sets of the United States collectively draw the power equivalent of a Chernobyl-sized nuclear plant when they are turned OFF! They use this power for their instant-on capacity, so we don’t have to wait a minute or two for our screens to warm up.

These facts and many more are contained in a small book called Practical Home Energy Savings. It’s a guide to reducing your energy costs by a lot, while protecting the environment and preventing the next war in the Middle East. It also contains some great nuggets for dinner-party conversations. The U.S. has five percent of the world’s population and uses 23 percent of the world’s energy.

The “efficiency dividend” could be bigger than the “peace dividend.” Poor insulation, inefficient appliances, drafty doors, and other fixable faults cost U.S. consumers over $300 billion per year — more than the military budget.

Superinsulating windows let in more heat than they let out, even on the north side of the house. These windows outperform the best insulated wall, because they both conserve furnace heat and gather solar energy. If everyone in the frostbelt installed them, the nation would save as much oil as we now get from Alaska — which we ought to do, not only to stop more oil spills, but because oil production in Alaska has peaked and is steadily declining.

Beyond listing jazzy facts, Practical Home Energy Savings lists what you can do to save energy, starting with what can make the biggest difference fastest and cheapest. First, it says, stop drafts. The average U.S. house has a total of five square feet of holes through which air leaks. These leaks increase the average heating and cooling bill by 30-40 percent.

Begin, says the book, with the holes a cat could crawl through. It tells you where you are likely to find them and how to eliminate them.

Step two is insulate.

Step three: get efficient about hot water. For example, run your shower full on into a gallon container. If it takes less than 24 seconds to fill, you need a water-efficient showerhead. If your family takes an average number of showers, the low-flow head will pay for itself in smaller hot-water bills within four months and earn you a profit after that.

Step four: Install windows that separate heat from cold, says Practical Home Energy Savings, which tells you where to find them.

Step five: Buy efficient appliances.

Refrigerators, for instance. Between 1950 and 1975 American manufacturers managed to triple the amount of electricity it took to run the average refrigerator — to a peak of 1800 kilowatt-hours per year. In 1976 California turned that trend around by prohibiting the sale of refrigerators requiring more than 1400 kWh per year. Within four years all manufacturers had met that standard. Now federal law requires a maximum refrigerator energy use of 940 kWh per year. The best automatic-defrost model on the market uses 770. The leading-edge eco-refrigerator uses only 240 kWh per year for a full-size unit.

For warming small amounts of food a microwave oven can save a third of the power of a conventional electric stove. But you waste energy twice over if you use the microwave to thaw frozen foods. Plan ahead. Let them thaw in the refrigerator. You’ll not only save heating energy, you’ll also reduce the load on your refrigerator motor.

For the home office: inkjet or dot-matrix printers use only 4 percent and 15 percent as much energy, respectively, as laser printers. Color computer monitors use twice as much energy as black and white ones. It does not make sense in either energy or disk-saving terms to leave a computer on when you’re not using it.

Compact fluorescent lightbulbs — 2-3 times more efficient than regular bulbs — come near the bottom of the home energy-saving list. Lighting is a big energy user in the economy as a whole; it takes 20 percent of all the electricity used in the United States. Some 50 to 90 percent of that energy could be saved without cutting down on illumination. But most lighting is used in the commercial and industrial sectors. Lights account for only 10-13 percent of home electricity consumption.

But compact fluorescent bulbs can save money in the home too, especially where lights are on at least four hours a day. Over its lifetime ONE BULB will save $40 in electric bills and $5-$10 in replacement costs, and it will save the earth a ton of carbon dioxide and 20 pounds of sulfur dioxide from a coal-burning electric plant, or 1 1/4 barrels of oil from an oil-burning plant (enough to run an average car 1000 miles), or half a curie of high-level radioactive waste from a nuclear plant.

Because of the energy savings already practiced by Americans, the nation’s annual energy bill is about $150 billion less than it would have been. If we were as efficient as West Europe and Japan, we could save $200 billion a year more — $800 for every man, woman, and child in the country. And, says this book, it’s possible to do even better than that.

Practical Home Energy Savings, $8 postpaid from Rocky Mountain Institute, 1739 Snowmass Creek Road, Snowmass CO 81654-9199.

Copyright Sustainability Institute 1992