Angie Zarrillo moved into her first house this year, a fixer-upper built in 1923 in Independence, Mo., with hardwood floors and a breakfast nook. So far, the handiest tool for renovations hasn't come from a kitchen drawer or the garage, but inside her purse.

Zarrillo uses mobile applications -- commonly called apps -- on her smartphone to select paint colors, discover ways to rework flea market furniture and learn quick fixes to common household challenges.

"I type in a problem and find an answer," said Zarrillo, a high school family and consumer science teacher. "For example, 'How do you clean paintbrushes?'" Solution from the app: a simple mix of water and dish soap with a picture of Dawn detergent.

Maxwell Gillingham-Ryan, founder of the blog Apartment Therapy, says home-related apps have changed since they were new to the scene three or so years ago.

"They've always had a fun factor, and the promise was good, but now they deliver on it," he said. For example, using your phone as a level to hang pictures or to do woodworking has moved beyond gimmick to functional. "The iHandy Carpenter app is really like a pocket Swiss Army knife of measuring tools."

Tablets up the ante

The other innovation that has affected home-related apps is the tablet computer, introduced two years ago with the iPad. The screen is larger than a phone's, yet the computer is lightweight enough to be easily portable, better for looking at floor plans and color palettes on the go. Nearly one of every five adults in the U.S. now has a tablet, according to the Pew Internet and American Life Project.

The increasing popularity of tablet computers has coincided with the rise of home-design photo library sites and their apps. Zarrillo's favorite is Pinterest, which lets users "pin" images from the Web onto virtual bulletin boards.

Pinterest has grown from about 1 million users a year ago to about 23 million this past July, according to Earlier this month, Pinterest opened its online service to the general public, ending years in which users who signed up had to wait to be admitted by the company. Also last month, Pinterest introduced an app for Android-based smartphones and the iPad (the company launched an iPhone app in March 2011).

Pinterest comprises a smattering of categories, including recipes and memorable quotes -- think online scrapbook. Interior designer Laura McCroskey of Kansas City, Mo., prefers the app Houzz because it's professional-looking and focuses solely on home design. Houzz includes a library of more than 625,000 images submitted by architects and designers that users can browse by style (Asian, contemporary, eclectic, Mediterranean, modern, traditional and tropical) and by room -- everything from basements to wine cellars. Users can create idea books for remodeling or building their dream home.

"It's a great communications tool for me and my clients," McCroskey said. "It also has examples of products, so instead of me lugging huge catalogs and wallpaper books around, this makes it more efficient."

Houzz users also can search by city. Some of McCroskey's clients have found her through Houzz, where rooms she has designed have been added to users' photo libraries. A little boy's nursery she designed has been added to 9,720 idea books.

McCroskey also uses DecorPad, focused solely on home design and with room-by-room searching capabilities like Houzz, but in a fun layout similar to Pinterest.

There's room for opportunity in home-related apps because more people are buying smartphones. Consider the stats of 2012: Nearly half (46 percent) of American adults are smartphone users, according to Pew research.

Gillingham-Ryan says apps that allow you to control things at home while you're at work is a category open for innovation.

"For years we've heard that we'll all be able to preheat the oven and so on through apps," Gillingham-Ryan said. "It seems like that's been slow to come."