A home-buying frenzy is pushing prices to record levels in a number of metro Phoenix neighborhoods, delivering double-digit increases in many spots and solid gains nearly across the board.

But the sharp run-up, driven by a growing population, first-time and move-up buying, and a surge of investor speculation, has some experts concerned that the market may be overheated.

The median price for a resale house in metro Phoenix has hit one record after another this year and stood at $179,500 in September, up $22,000, or nearly 14 percent, from $157,500 in the same month last year, according to the Arizona Real Estate Center at Arizona State University.

Many Valley neighborhoods racked up substantial gains through August, some of them extending an unbroken five-year streak of appreciation, according to The Arizona Republic's analysis of home-sale data from Marketron.

"The market's current activity is unsustainable," said Jay Butler, director of the Arizona Real Estate Center at Arizona State University.

Other trends driving metro Phoenix housing:

• Soaring prices in other Western cities are helping spark an influx of speculators.

• Pinal County beckons those looking for a deal on a new house.

• North Scottsdale has been a hot spot for price rises. Now, Sun City and Youngtown join the party.

• The West Valley is becoming a top market.

- Glen Creno and the Arizona Republic: October 24, 2004