Q Our home is 20 years old, and we need to replace the original roof. Internet research has turned up a claim that a metal roof can reduce energy costs by up to 15 percent. Does this hold true in Minnesota?

A Yes and no. Metal roofs can reduce energy costs from 10 to 50 percent, according to Xcel Energy's Erin Mathe. But the benefits are reduced in Minnesota because we don't use nearly as much air conditioning.

"Homes and buildings located in hot and sunny climates will realize the greatest energy and cost savings," Mathe said. "So, people living in Southern geographic areas that use more air conditioning will see greater reductions in their energy bills than people living elsewhere in the country."

But that 15 percent threshold is certainly achievable here, even without a metal roof.

Brushing a reflective coating onto a shingled roof can reduce peak cooling demand by 10 to 15 percent, Mathe said, enabling homeowners to purchase smaller, less expensive heating, ventilating and air-conditioning systems.

"Uncoated shingled roofs typically absorb around 80 percent of the sunlight that hits them, heating your home in the summer and driving up your air-conditioning bill," she said. "A coated roof, however, can reflect about 80 percent of heat."

While metal roofs also reflect most sunlight and thus keep a house cooler, the total energy savings depend on insulation levels, the slope of the roof and how well the roof is cleaned and maintained, Mathe said.

The most efficient approach, according to Mathe: metal or single-ply membrane roofing, and roof-coating products. The least efficient: 15-year non-recycled shingles.

For more information on roof savings, see www.roofcalc.com.

BILL WARD

Q I've heard that Minneapolis prohibits the use of retractable dog leashes. Is this true? Can dog owners get fined for using them?

A Neither the city of Minneapolis nor the Minneapolis Park and Recreation Board has any ban on retractable dog leashes, so you can feel free to use yours without being fined. If you do choose to use a retractable leash at one of the parks operated by the board, however, you must keep it within 8 feet.

"Certainly, we're not out there looking for people with 9-foot leashes, but our trails are so congested that it's somewhat self-policed by the number of park users we have," said Dawn Sommers, public information manager for the Park and Recreation Board. "People are typically pretty respectful of the fact that a lot of people are on our trails."

Ben Jones

Send your questions to Fixit in care of the Star Tribune, 425 Portland Av., Minneapolis, MN 55488, or call 612-673-7032, or e-mail fixit@startribune.com. Sorry, Fixit cannot supply individual replies. Fixit appears Sunday on Page B3.