But across much of California and the Northeast, prices are now high enough that the costs of owning a home – property taxes, repairs, fees to real-estate agents and mortgage interest – may outweigh the financial benefits, including the tax break.

It is the latest change in a yo-yo pattern over the past decade. From 2004 to 2006, the math overwhelmingly favored renting rather than buying across most of the country, even as many Americans mistakenly decided that home prices could never fall. From 2009 to 2011, buying was an extraordinary deal in most of the country. Even the markets that have experienced huge price increases are far from the clear-cut bubble conditions of the mid-2000s, but they’re inching closer with every bidding war.

Since the start of 2011, prices have risen 33 percent in the San Francisco area, 30 percent in Miami, 24 percent in Los Angeles — and even more in some of the most desirable neighborhoods within those areas.

In the San Francisco Bay Area, home of the sharpest recent price increases, the sale price of a home is about 20 times what it would cost to rent a home of the same size for a year. That ratio, based on an analysis of data from Zillow, is the same as in 2003, when the San Francisco real estate market had yet to become an out-of-control bubble but was well on its way there.

When low mortgage rates are taken into account, buying a home in San Francisco looks somewhat more attractive — but with a 10 percent down payment and prevailing interest rates, buying a home is 6 percent more expensive than renting a place of the same size, the same premium for buying as there was during the dot-com boom in 1999. Just two years ago, buying in the San Francisco area was 24 percent cheaper than renting an equivalent place.

The potentially overvalued markets are the result of three forces. They are taking place in local economies that suffered only minimally during the recession that began in 2008 and have experienced strong job growth since then.

They are fueled further by the low-interest rate policies that are aimed at bolstering the overall national economy but don’t discriminate based on geography. Even as San Francisco’s housing market is at risk of overheating, buyers there get the same ultralow mortgage rates engineered by the Federal Reserve as home buyers in depressed Detroit or Cleveland do.