Uncertainty in home values means a greater demand for rental units

Investors become acclimated to ups and downs in the real estate market, but homeowners have good reason to expect continual increases in the value of their house. That's the way it's been for decades, right?

Well, in some areas of the country, that picture is changing - dramatically.

If you were relocated early this year from Louisville, Ky., to New York City, for example, you would have lost substantial ground in your home-investment status. During the first quarter of 1984, the median-priced house in Louisville sold for $47,900, an 8 percent drop in value in just one year.

In the New York area, by contrast, the first-quarter median house price was $ 100,500, an increase of 21 percent during the same one-year period.

That's an extreme, but actual, comparison of house-price trends now taking place in the United States. It depicts the diverse nature of house values in varying regions of the country.

According to a report issued by the National Association of Realtors (NAR), Louisville has the lowest median house price and experienced the greatest one-year drop in house prices. On the other hand, houses in metropolitan New York showed the largest one-year increase in value.

If you and your family had moved from Louisville to Santa Ana, Calif., instead of New York, your housing situation could have been much more serious. You would be moving from a $47,900 median-price area to a $133,500 median-price locale.

The lesson to be learned is this: House prices and trends vary greatly in different parts of the country. When you read about national averages, it doesn't necessarily apply directly to your community. At the same time, the national averages are interesting and significant when considered in the right perspective.

The national median price of resale houses during the first quarter of this year was $71,800, the NAR report states. That's a 5 percent increase over the median-house price one year earlier.

Such figures also can vary substantially from survey to survey. Another survey at the same time by Better Homes and Gardens Real Estate Service, a national franchise organization of 450 member realtor firms, showed an average resale house price of $84,013.

Fluctuating house values is one factor contributing to the decline in the proportion of households owning their residences. A few years ago, a family's house was obviously the best possible investment. It seemed that values would always be on the upswing. Now that certainty no longer exists.

The proportion of households owning their homes peaked at 67 percent a couple of years ago. Now it's about 65 percent. By the turn of the century some observers predict that the figure will be down to 59 percent.

One factor bringing that percentage down, according to housing analysts, is the uncertain nature of house-value trends. Buying a house is still a choice investment form for most families, but it doesn't offer the secure ''profit potential'' that was the case only a few years ago.

One problem created by these trends is a shortage of rental units in some areas. Increasing interest rates on construction loans and community rent-control restrictions are discouraging builder-developers from starting new multi-unit rental developments in many locations.

The increasing demand for rental housing, however, is expected to stimulate the planning and construction of such developments during the next few years. The rental market is heating up, and more than one-third of the nation's households already reside under a rented roof.