Potential home buyers, who have been frustrated by fast-rising mortgage rates twice in the past year and then teased by a short-lived decline in early summer, are approaching autumn with perplexity.

Their decisions to buy a house, town house or condominium apartment must take cognizance of mortgage rates that make monthly payments higher while balancing that deterrent against the prospects of continuing inflation. In the 1970s, that pattern resulted in both new and existing houses more than doubling in marketable value in less than 10 years.

Skepticism about the future deters some home owners from thinking about a larger or more expensive dwelling on which financing costs will be higher. They also know that sellers today are faced with extra cost (in terms of high mortgage discount points) that must be paid to obtain either FHA or VA financing for buyers who want to go that financing route. And conventional mortgage rates are now over 13 percent again.

Any prospective home buyer or current home owner considers a house an investment that will both appreciate in value and also provide tax deductions for mortgage interest and taxes. Those tax factors are major incentives for both modestly and exceptionally affluent persons to own expensive houses.

Now home builders are unable to enjoy a recent rebound in construction after a debilitating six-month hiatus. "That light we thought we saw at the end of the tunnel in June may not have been sky after all but another high-interest rate train rolling our way," commented California Merrill Butler, president of the nation's organized home builders.

Unusually high mortgage financing costs tend to turn away discretionary home buyers and sellers. Another round of tight-expensive credit for home buying and home building could deflate a housing upturn that seemed ready to occur this fall. Meanwhile, some builders of new dwellings still have below market financing rates for prospective purchasers.