Median apartment rents across the metro area rose 13.4 percent the first quarter, but vacancies also ticked up as more new high-end units came onto the market, according to the Denver Metro Area Apartment Vacancy and Rent Survey.

The median monthly apartment rent across the seven-county metro area rose to $1,158.26 in the first quarter, up from $1,123.81 in the fourth quarter, and $1,021.29 a year earlier, according to the survey, released Tuesday.

The metro-area apartment vacancy rate increased to 4.9 percent in the first quarter, up from 4.7 percent the previous quarter. Developers added 1,560 new units, bringing the metrowide apartment inventory to 307,268.

“That translates to over 15,000 available apartments for those seeking to rent,” said Mark Williams, executive vice president of the Apartment Association of Metro Denver, which sponsored the report.

Vacancy rates varied widely across the metro area, with Jefferson County at 3.2 percent, while Denver County was nearly twice as high at a still-tight 6.3 percent.

The hottest metro apartment markets were north Aurora, which is showing as fully rented; Wheat Ridge, with a 1.6 percent vacancy rate; Longmont, 1.8 percent; north Lakewood, 2.2 percent; and Arvada, 2.3 percent.

Downtown and northwest Denver, where several new higher-rent developments have located, had vacancy rates of 11.1 percent and 11.4 percent, respectively. Other “softer” markets include Broomfield, 9.2 percent vacancy rate, and Littleton, 13 percent.

Newer buildings, those built since 2005, had a 12.9 percent vacancy rate, while some of the oldest and most affordable buildings, those built between 1940 and 1949, had only a 0.7 percent vacancy rate.

Rents in Denver and 13 other large cities were compared in the report, in part to address complaints that Denver is becoming an expensive rental market.

At $1,440 a month, a two-bedroom apartment in Denver rents for less than similar units in San Francisco, Los Angeles, Boston, Washington, Seattle, Miami and Philadelphia.

San Francisco, the most expensive market surveyed, had rents of $2,735 a month for a two-bedroom apartment.

But Denver isn’t land-constrained like most more expensive apartment markets. Rents here have outpaced comparable markets with land availability such as Atlanta, Dallas and Phoenix, where renting a two-bedroom apartment averages $948 a month.

Metro Denver has top national rankings for both apartment-rent increases and home-price appreciation in recent months, and housing costs have outpaced income gains and overall inflation.

Aldo Svaldi: 303-954-1410, asvaldi@denverpost.com or twitter.com/aldosvaldi