1. Add insulation. An estimated 80 percent of older homes are underinsulated. Properly insulating and sealing your home can cut your heating and cooling bills by 10 percent.

2. Plant a deciduous shade tree on the west and southwest sides of a house to save energy.

3. Open blinds and shades on cold days. Solar heat gain can raise interior temperature significantly. But close them at night to minimize heat loss.

4. Put your PC to sleep. Save $75 or more by using the system standby or hibernating feature.

5. Plug electronics into a power strip so that you can turn them all off at once.

6. Install a high-efficiency showerhead. It will reduce hot water use by up to 50 percent.

7. Upgrade to a low-flow toilet and save 4,000 gallons per year.

8. Control outdoor lights with sensors or timers so that fixtures stay off during the day.

9. String LED lights this holiday season. They last longer. Tests have shown that they can save up to $11 per season.

10. Weatherstrip old windows and doors. It's the surest way to close the gaps around openings, reducing heating and cooling costs by 15 to 30 percent.

11. Lower the temperature a degree or two before guests arrive. A house full of people generates a lot of body heat.

12. Move the thermostat to an inside wall away from windows and doors so that drafts don't cause the heating system to cycle on unnecessarily.

13. Zone heat smartly. A portable heater in a room saves money only if you're willing to keep the rest of the house chilly. Wood-burning fireplaces can suck more heat from your home than they put back in.

14. Dust off the slow cooker. You'll use a lot less energy than cooking a meal across several burners and in the oven.

15. Skip pre-rinsing dishes. Tests have found it's unnecessary, and you'll save up to 6,500 gallons of water per year.

16. Clean the coils behind or underneath your refrigerator with a tapered appliance brush to keep it running efficiently.

17. Keep car tires properly inflated. In Consumer Reports' tests of a Toyota Camry, fuel efficiency dropped by 1.3 mpg when the tires were deflated by 10 psi.

18. See if your utility company offers rebates to customers who replace old appliances with energy-efficient models. Some states hold periodic "tax holidays" for purchases of energy-efficient appliances.

19. Opt for the cold-water wash cycle and save about $60 a year.

20. Don't overload the dryer. Clothes will take longer to dry, and they'll come out wrinkled. When the weather is warm, line dry.

21. Insulate and seal cracks and gaps in your ducts. That can help reduce energy costs by 30 percent.

22. Clean or replace furnace filters monthly during the heating season. Clogged filters force the blower to work longer, raising your electric bills.

23. Lower water-heater temperature to 120 degrees from 130 and insulate hot-water pipes to knock up to 5 percent off your energy bills.

24. Drain a bucket's worth of water from your water heater a few times a year to remove sediment, which can decrease efficiency.

25. Call a professional energy auditor. They use a blower door or infrared photography to pinpoint where your home is leaking energy. Some utilities provide free audits. You can also find certified professionals on the Web site of the Residential Energy Services Network or RESNET at www.resnet.us, which lists four in Pittsburgh and several others in southwestern Pennsylvania.