Jun. 27--Some people reading this column are dreading going outside today -- and for good reason. The high temperature is expected to hover around 100 degrees, and even the morning weather promises to be insufferable.

If you've got air conditioning in your home, there's no reason to go anywhere. But, while you're staying indoors, today might be a good day to make several baby-step improvements in your home's energy efficiency. They'll keep your house cooler, and they'll shave a few bucks off your peak-season electricity bill.

The tips below -- culled from Ameren, Consumer Reports and the federal government -- offer quick, easy and free ways to make your home comfortable and a little bit more energy efficient during the oppressive summer heat. But don't kid yourself into thinking that any of this advice will do much to counter the bad effects of ancient appliances, poor insulation and rickety exterior doors and windows.

When it's about 100, every bit helps.

BOOST WINDOW UNIT EFFICIENCY

If you use window units, they are probably overdue for some TLC. Consumer Reports suggests washing the filters gently in warm, soapy water once every month. You should also vacuum any debris from around the coils for maximum efficiency. (If you have central air, experts suggest leaving most maintenance tasks to a professional.)

Depending on where those window units are located, you could get a lot more bang for your air-conditioning buck. According to the U.S. Department of Energy, window units installed on shady parts of a house run up to 10 percent more efficiently.

While a hot summer day is no time to move air-conditioning units, Ameren suggests using a trellis or other shade-creating device to cool off window units located in direct sunlight. Just make sure not to block the air flow.

LOWER THE AC WHEN YOU'RE OUT

Unless you keep pets indoors, you're wasting money by running air conditioning in an empty house. Instead, pull the blinds tightly closed -- making sure that the slats are turned to reflect up and out -- and set your central air to 85 degrees or so. Shut window units off.

You might think it'll take hours to cool down the house when you get home, but most AC systems will chill the place down within a half hour or so. If that's still too long, install a programmable thermostat to get the process started before you get home. If you use window units, hook them up to a heavy-duty timer designed for that purpose. (Don't use the ones designed for switch-on lamps; they won't work on air-conditioning units.)

MAKE LESS HEAT

Just about everything that runs on electricity generates heat.