Every year, thousands of Arizona residents email Rosie Romero's website or call his radio show with questions about everything from how to prevent fires in their chimneys to what to do about the tree roots invading their sewer systems. One of his goals is to provide answers that suit the specific lifestyle wherever someone lives in Arizona.

QUESTION: I have a 20-year-old pitched roof with three-tab asphalt shingles on it, and I'd like to put a white coating on it to reflect the sun. Is that possible?

ANSWER: They do sell reflective coatings that can be used to paint on top of asphalt shingles. However, using that type of coating for old shingles is not always recommended by manufacturers. Your roof may be getting close to the end of its useful life anyway. You might be better off replacing it completely with what are called "cool" asphalt shingles manufactured with specially coated granules that will provide better solar reflectance.

Q: When I close the air conditioning register in our master bedroom, the register rattles like crazy when the air comes on. I'm closing it actually in order to get the other bedrooms in the house to cool off more.

A: We don't recommend closing off air conditioning vents in one room that seems cooler than others. When you do that, you can create extra pressure on your HVAC system. It can actually cause air to leak through the ducts in your attic, wasting energy and money.

If you are having trouble with hot spots in your house, you should have an air conditioning professional look at your whole system and see if some repairs can be made in the ducts.

You might also want to invest in better quality registers. Buy an OBD or opposing-blade damper for each room. They'll cost a little more - about $12 to $15 - but they won't rattle, and you can use them to modulate airflow better. Close all of them slightly so they are about 60 percent open; try that for a couple of days to see if the system works better.

Q: I have been replacing older appliances throughout my house but have not yet replaced my 11- year-old water heater. However, I've noticed that my water doesn't seem to be as hot as it used to be. Is there some kind of routine maintenance I can do that could improve its performance, or does it have to be replaced also?

A: Unfortunately, there is no kind of regular maintenance that you can do on a water heater every 11 years. At this point, you don't want to touch it; you don't want to try to flush it out. Chances are that it's on its last legs and will probably only last a year or two more. Over the years, all the sediment that runs through your water lines has been building up at the bottom of that tank, particularly if you don't have a water softener. If you drain out the water, that sediment will remain in the bottom of the water heater, and when the gas burner comes on, it will cook into one big chunk.

When the day arrives that you do replace the water heater, however, that's when you should start maintaining it by flushing it out regularly to remove the sediment. Have the company that installs the water heater put a good, solid-brass ballcock valve on the front so that you can easily flush the water out when you want to.

Q: I have a preformed, poured concrete fountain in my yard that keeps developing calcium stains due to the water that runs through the fountain. I would like to paint the fountain white to cover the stains, but what paint could I use that will stick to the concrete?

A: It's unlikely that you can find a paint that will cover the fountain and stay on it. Concrete of this type is a very porous product, something like a hard sponge. As the fountain runs, the concrete will always keep getting wet behind the paint and the paint will peel off. You might have to replace the concrete fountain with a plaster structure in order to deal with the calcium buildup problem.

For more do-it-yourself tips, go to rosieonthehouse.com. An Arizona homebuilding and remodeling industry expert for 25 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) and -FM (97.1) in Tucson and KGVY-AM (1080) and -FM (100.7) in Green Valley. Call 1-888-767-4348.