Strong demand for apartments in the Houston area pushed average rents over the $1,000 mark for the first time, a new report showed.

The average rent climbed 6.3 percent year-over-year in the third quarter, to $1,007 per month, commercial real estate firm Marcus & Millichap said.

The apartment market should remain hot as concerns about the economy keep some potential home buyers on the sidelines, the report said.

Apartments in the Downtown/Montrose/River Oaks submarket fetched the highest rents, rising 3.9 percent year-over-year to $2,010 per month in the third quarter. Rents went up most in the Spring/Tomball area, rising 15.5 percent to $1,056 per month.

Vacancy in the quarter fell to 5.2 percent in the third quarter as 14,800 more units were leased year-over-year.

Markets with the lowest vacancy were Friendswood/Pearland and Gulfton/Westbury at 3.4 percent. Spring/Tomball, where number of apartments grew by 20 percent, has the highest vacancy at 7.3 percent.

In the last four quarters, 14,400 units were completed across the Houston area.

Nearly half of the apartment units under construction that are expected to be completed this year will be finished in the fourth quarter, according to Marcus & Millichap. That is projected to push vacancy to 6 percent.

Even with the higher vacancy, average rents are projected to end the year 4.6 percent higher at $1,005. That's on top of last year's 5.8 percent rise.

Apartment Data Services, a Houston-based firm that tracks the local apartment market, showed similar findings.

Rent levels at Class A properties have flattened as more complexes have opened and properties are paying more in concessions, Bruce McClenny, president of Apartment Data Services, said in a recent email. Other classes are still able to raise rents, pushing up the average.