Housing experts differ on some of the details, but there seems to be general agreement that 1981 won't be an outstanding year for either buyers or builders.

In keeping with the theory that it's smart to know what to expect, here are some of the opinions:

Sanford R. Goodkin Research Corp., a real estate and financial advisory service based in Del Mar, Calif.: Shortages of both land and money will be the major problems of the housing industry this year.

"Land still goes through its over-regulation, with very few local governments admitting what that costs," said Goodkin, chairman of the firm. "Federal policies will be come more rational in regards to environmental protection and land use, but it is the local people who create the long zoning waits and downzoning."

He said financing of homes is going through a revolution instead of an evolution. "The financial institutions have conditioned us to the reality that money is expensive, so to borrow it you have to give a piece of the action, equity or just pay a lot for it. The lenders have been seeking the highs within which their monies can still be viable.

"It appears that this is perceived as somewhere between 12 and 13 percent, which they [lenders] hope is accepted as 'cheap.' It isn't, regardless of tax shelters, Goodkin said."

Herman J. Smith of Fort Worth, Tex., president-elect of the National Association of Home Builders: Mortgage interest rates will remain in the 12 to 14 percent range and "put a serious drag on new home sales." Smith recommended creation of a tax-exempt or tax-deferred savings plan for housing to provide mortgage funds at a lower rate than is now available.

Michael Sumichrast, chief economist of the NAHB: "President-elect Ronald Reagan is not likely to give housing a higher priority than it had under the man he defeated on Nov. 4. In fact, housing may be less a priority under Reagan. However, what is likely to develop is a climate that will be more accommodating to long-term stability of interest rates."

Kenneth Thygerson, chief economist for the U.S. League of Savings Associations: "Conventional mortgage rates should be in the 12 1/2 to 14 percent range in 1981, with higher rates during the earliest part of 1981."