If you want to redo your roof, get bids from companies on file with the Arizona Registrar of Contractors.

Each year, thousands of Arizonans email or call our radio show with questions about everything from preventing fires in their chimneys to getting rid of tree roots invading their sewer system. Our goal is to provide answers that suit the specific lifestyle wherever someone lives in Arizona.

QUESTION: Sales teams for roofing contractors are traveling around our neighborhood and are aggressive about trying to get people to sign contracts for reroofing. Sometimes they even put signs on the lawn to advertise their companies and climb up on your roof to inspect it without asking for permission first. How should we handle this?

ANSWER: Don’t even open the door when those roofers ring your bell and never sign contracts with home improvement contractors or companies that come uninvited onto your property. If you’re interested in redoing your roof, you want to have inspections done by reputable companies that are on file with the Arizona Registrar of Contractors. Any contractor you hire needs to be licensed, bonded and insured. You want to get references from a contractor’s past clients, too. It’s also good to get bids from three contractors.

Q: Can I put a portable evaporative cooler in my attic? I’m thinking it would fill the attic with cool, moist air and that might help cool the rest of the house.

A: It could be very costly to do that. An evaporative cooler could cost as much as $2,000. Then you’d also spend lots of money running it as well. It would be many, many years before that cooler would pay for itself in terms of cutting your energy bills for air conditioning. One additional problem is that you’d need to have a window or windows open in the attic when you run the cooler.

Q: I live in a 3,900-square-foot house and have two air conditioners and five air return vents. Currently, I’m buying filters for the air intake vents that cost $25 each, and I change them every month. Is that expense really necessary?

A: One-inch paper pleated filters would be fine to use in the air intake vents in your house, provided that your air ducts have been properly cleaned and sealed. You only want to buy expensive filters if you have a problem with allergies and need to filter out small particles from the air. A cheaper filter will work fine.

Q: I have a 1,250 square foot, 2-bedroom house, and my Arizona Public Service bill seems pretty high during the summer for a smaller home.

A: The most important thing to remember: Try not to consume any electric power in your house during the on-peak hours for rates, which start at 3 in the afternoon on weekdays and last until 8 p.m. for Arizona Public Service customers and until 7 p.m. for Tucson Electric Power customers. Pre-cool your house as cold as you can stand it earlier in the day, and then turn off or decrease the setting on your air conditioning at 3 p.m. If you do that, you’ll do a lot better on your bill.

Q: I had a lot of excess water running out of the outdoor condensation tube for my air conditioner. The coils were also frosted and covered with dust. The repair man took care of all that, but he also replaced the capacitor on my 9-year-old air conditioner. Was that new capacitor really necessary on such a new unit?

A: It does sound like that repair man did a really good job on your AC. It’s possible that a new capacitor was needed because capacitors don’t last very long. A capacitor is something like a car battery. It’s the device that sends an electrical jumpstart to your AC system. Capacitors deteriorate gradually and can burst when they wear out.

For more do-it-yourself tips, go to rosieonthehouse.com An Arizona home building and remodeling industry expert for 29 years, Rosie Romero is the host of the syndicated Saturday morning Rosie on the House radio program, heard locally from 8-11 a.m. on KNST-AM (790) in Tucson and from 9-11 a.m. on KGVY-AM (1080) and -FM (100.7) in Green Valley. Call 888-767-4348 with your radio questions.