Q I have a house in Phoenix. During the summer when no one is living there, is it better to leave the air conditioning set at 85 degrees, or should I turn it off completely? The daytime temperature can reach 110 degrees, but I'd like to save on electricity.

A Commonly, it's best to leave the air conditioning on in Arizona homes. They are very different from Minnesota homes in materials and systems, and the climate conditions are almost the opposite. But you may be able to turn it off, if you do so carefully.

Take these extra steps to protect yourself and your home:

• Many household items are vulnerable to extreme heat and the results can be surprising: Candles may melt into puddles of wax; aerosol cans may burst, spreading contents over a wide area. Go room by room to identify any items that would be damaged by heat and store them in an air-conditioned space while you're gone. Check labels carefully.

• Appliances such as refrigerators and freezers would be stressed operating in high temperatures. Empty and clean them before unplugging, and fix doors in an open position.

• Household grain-based foodstuffs such as flour may spoil over an extended period and attract insects. Dispose of them or store them elsewhere.

• Shut off water and drain the water system within your home, including the water heater. If a small leak were to occur, it would feed the growth of mold.

• Water will easily evaporate from traps serving sinks, baths and toilets, permitting the entry of sewer gases as well as insects and other pests. Use an RV antifreeze in plumbing traps to prevent that from happening.

• Dryer vents, usually close to ground level, may become entry points for pests. Clean the vent of accumulated lint, then use steel wool to plug the vent. (Place a "WARNING" reminder to remove the blockage before using the dryer.)

• Tuck steel wool under the edge of siding around the bottom of your home to keep rodents from entering.

• Gasoline stored in hot conditions will aggressively evaporate from cans and motor fuel tanks. When gasoline evaporates, it leaves a heavy varnish-like deposit on surfaces. Decant gas from tanks, run the motor until tanks are dry or give the fuel to someone else.

• Gutters can accumulate debris, get plugged up and hold water that permits plant growth or attracts birds and other animals and potential damage. Hire someone to clean them or install covers.

• Arizona has reptiles, requiring more precautions. Information on reptiles, rodents and other pests may be best gained through your Arizona University Cooperative Extension Service (http: //cals.arizona.edu/extension).

• Check with local utilities for recommendations on shutting up a home over the summer.

• Just as an unshoveled drive and sidewalk indicate absence over a Minnesota winter, an accumulation of plastic bags, advertiser newspapers, etc., also indicates a vacant home. Lights on a timer can feign occupancy. Have a neighbor check your home periodically to pick up papers and deter theft. Notify your local police of your absence and planned return dates.

• Many developer-built communities of single-family homes in Arizona have services provided by homeowner associations. If your home is in one of these communities, check to see if a "snowbird" service is available.

• Don't forget to make a list of all the actions you've taken so that when you return, you can reverse the process.

Phil Smith, Minnesota Office of Energy Security

Send your questions to Fixit in care of the Star Tribune, 425 Portland Av. S., Minneapolis, MN 55488, or call 612-673-7032, or e-mail fixit@startribune.com. Past columns are available at www.startribune.com/fixit. Sorry, Fixit cannot supply individual replies.