Number of Houses Sold Falls Again; Prices Hold : Real estate: The Gulf War and low consumer confidence are cited in the 20% drop in sales of Valley residences in January.

The area’s housing slump continued in January as sales of existing single-family houses dropped 20% from the previous month and plunged 37% from a year earlier, the San Fernando Valley Board of Realtors said Monday.

Low consumer confidence, weakened by concerns about the nation’s economy and the Persian Gulf War, are keeping a lid on local housing sales just as they are around much of the nation. Last week, the California Assn. of Realtors said those factors led to a 17% decline in single-family house sales statewide in 1990 compared with the previous year.

Sales continue to slide, even though the cost of financing a new house has fallen sharply in recent weeks. Interest rates on conventional 30-year, fixed-rate mortgages have dropped to between 9% and 10% following efforts by the Federal Reserve to lower credit costs generally.

“It’s obvious that interest in home buying has taken a back seat to the war in the Persian Gulf,” Steve Owen, president of the Valley’s realty board, said in a statement. “These sales numbers reflect the depth of the public concern, just as it is apparent in virtually every sector of the economy.”

Last month, the Valley realty board said 488 detached single-family houses were sold, down from 609 in December and 770 in January, 1990. Meanwhile, the number of houses listed for sale was flat last month at 8,546.

Despite the sales slowdown, housing prices in the Valley remain firm. Last month, the average resale price of a single-family house rose 2%, to $297,300 from $292,100 in December, and was nearly unchanged from a year earlier, when the average price was $298,300, the board reported.

The record high average resale price for Valley single-family houses was set in November, 1989, when it reached $313,100.

The median price of a house in January was $225,900, meaning half the houses sold for less than that price and half sold for more. That also was up 2% from December’s $221,500, but down 2% from $230,000 a year earlier.

Sales of Valley condominiums, meanwhile, fell 15% last month to 153 from 180 in December, and were down a whopping 50% from the 304 sold a year earlier. The average resale price of a condominium was $149,600, down 0.3% from $150,000 in December and down 4% from $156,200 in January, 1990.

But because interest rates are relatively low and because the supply of houses for sale is relatively high, the real estate industry is hopeful that sales will move upward once the war ends.

And at least one mortgage executive said his business is picking up now that rates have come down. “Our loan production has increased steadily over the last two weeks,” said Ira L. Cohen, senior vice president of ARCS Mortgage, a Calabasas-based unit of the Bank of New York. He added that most of the loans were for new purchases rather than refinancing existing loans.

The Valley realty board, California’s largest, reports housing sales by its members in the area from Agoura to North Hollywood. Its statistics do not include sales of most new residences.

January Valley Home Sales North West: Avg. Price: $267,600 Sales: 23 North Central: Avg. Price: $300,000 Sales: 77 North East: Avg. Price:$173,800 Sales: 81 South West: Avg. Price: $370,000 Sales: 113 South Central: Avg. Price: $306,200 Sales: 60 South East: Avg. Price: $310,400 Sales: 134