Today's tip is part of our Fiscal Fitness '09 series. Every weekday this month, you'll get help getting fiscally fit as we work toward our goal of saving $2,000 to invest in 3 stocks!

For centuries, parents have scolded their offspring about needless exposure to the elements. The most common admonishment: "Close that door! I'm not paying to heat the whole neighborhood!"

That advice never ceases to be relevant, particularly given the rising cost of utilities. According to the Energy Information Administration, about 42% of the average household's utility costs are devoted to heating/cooling. (The remaining breakdown is 14% on heating water, 36% on lighting/appliances, and 9% on refrigeration.)

Before you clear the backyard to install a windmill, try a little elbow grease. Big savings -- financially and atmospherically -- can be had by giving your home's biggest energy hogs (heating and cooling systems and major appliances) a little TLC. To butcher a cliche, an ounce of prevention is worth a pound of sweat.

Plug the leaks and cut your bill by one third
You can improve your home's efficiency by a whopping 30% simply by stopping your house or apartment from leaking money -- literally. Small air leaks contribute to more than one-third of heating and cooling costs. (For resources to help you do it see our rundown below under "More ways to save...") Plug the holes (e.g. replace weatherstripping, caulk holes around pipes, making sure ducts are leak-free) and brag to your dad that you're finally not paying to heat or cool the whole neighborhood.

Once you've plugged the leaks, a few easy chores will help your home run more efficiently:

  • Replace filters regularly: Simply changing the filter on your HVAC and cleaning the coil can improve your unit's original efficiency by anywhere from 5% to 20% each year. Regular checkups both improve efficiency, but also prolong the life of your appliances. (Remember Savings Rule No. 1: Don't spend it in the first place if you don't have to.)
  • Weather-proof. For a cost of approximately $50 on weatherizing supplies (window-sealing kits, sealing tape for doors and windows, and expanding foam), you can save $100 to $150 off your heating bill for just one winter season.
  • Use a water heater blanket. For an outlay of $20, you can significantly reduce the amount of heat loss from your water heater, earning back the money in energy savings in just a year. Consider insulating your pipes for increased savings.

For even more tips, see "Save 50% on Your Utility Bills."

Karma/cash in the bank
Vacuuming the coils on the back of the fridge and slipping Junior a few extra bucks to change the HVAC's filter make a bigger difference than you might think. If every household improved the energy-efficiency of our appliances by 10% to 30%, the reduced demand for electricity would be on par with shutting down 25 large power plants, according to the American Council for an Energy-Efficient Economy.

As for the cash-money bottom line, though an imperfect comparison, we'll use the amount the average household spends on utilities per year -- $1,500 -- and, if divided equally over 12 months, we're talking a savings of $12.50 to $37.50 a month. Our calculators can't measure the karmic payoff of a weekend of service to Mother Nature's cause, but we're sure it's pretty substantial.

More ways to save ...

  • Do a DIY home energy audit: Go to http://hes.lbl.gov/ and get an upgrade report that calculates your savings as well your return on investment and payback time in key areas (heating, cooling, water heating, appliances, and lighting). See what products earn the energy star seal of approval at energystar.gov. Find out if your state offers energy savings incentives at dsireusa.org and get the latest on Federal credits at energytaxincentives.org. If you need a hand, call your utility company and schedule an energy audit. Many perform these thorough inspections for free or a small fee (or offer rebates if you hire an outside company), and will identify trouble spots and make remedy recommendations.

  • Don't ignore appliances. Badly maintained appliances can cost more than you'd think. But while Sears (NASDAQ:SHLD) and Best Buy (NYSE:BBY) stock Energy-Star-compliant appliances from companies like General Electric (NYSE:GE) and Whirlpool (NYSE:WHR), simply making sure your existing appliances are in tip-top shape can save a bundle.

  • Maintain, maintain, maintain. Routine maintenance to your home's major systems (plumbing, heating and air conditioning, and gutters/roof) can help you avoid costly repairs down the road. Download a seasonal home maintenance checklist and get busy.

  • Get help. Anytime you want it, help is available. Stores like Home Depot (NYSE:HD) and Lowe's (NYSE:LOW) are happy to help you figure out what products could help your energy efficiency.

  • Insulate your attic. Upgrading your attic insulation from three inches to 12 inches can save you up to 20% off your heating bill and 10% off your cooling bill, estimates the American Council for an Energy-Efficient Economy. Insulation maker Owens-Corning (NYSE:OC) provides some useful resources on exactly what to do.

Read the latest from Fiscal Fitness '09: 1 Month, 2 Grand, 3 Stocks to get our other money-saving tips. You can also keep up with our tips through our daily Foolwatch email. Share your frugal insights and experiences through our Fiscal Fitness '09 discussion board, or leave a comment below.