A weekend house fire that killed seven people in McLean will do little to bolster legislative attempts to require smoke detectors in Virginia houses and apartments, area lawmakers said yesterday.

"This is not the first fire that's ever killed people," Del. Elise B. Heinz (D-Arlington/Alexandria) said of the deaths, which local fire officials said might have been prevented by detection devices. "The odds are against it making any difference (in Richmond)."

The blaze, which broke out early Saturday morning, killed five adults and two children sleeping inside a rented house at 2014 Great Falls St. One man survived.

A bill sponsored by Heinz in the General Assembly's 1980 session that would have allowed the Alexandria City Council to require detectors in some multiunit rental properties was defeated three times. That, Heinz said yesterday, indicates the problems such legislation faces in a state that is reluctant to place restrictions on businessmen.

"There's a feeling in Virginia that government gangs up on businessmen and makes them spend money on knee-jerk protection for people," Heinz said. "They don't want to violate the sanctity of private property."

Even if the legislation had passed, she asked, it would have done nothing to prevent loss of life in private, single-family dwellings. Others said the McLean fire pointed up the need for stronger legislation to be enacted on a statewide level.

"If you have that kind of disaster in a single-family house, just think of what you could have in an apartment dwelling," said state Sen. Wiley F. Mitchell (R-Alexandria).

Three years ago, the Virginia legislature decisively defeated a measure proposed by then-Del. Richard L. Saslaw (D-Fairfax) that would have required smoke detectors in all homes. Although neither the Saslaw bill nor Heinz's proposal offered stiff penalties for violators, some Northern Virginia legislators say the bills were defeated because of the implied economic threat they posed to the state's apartment owners and developers.

Under current Virginia law, smoke detectors are required only in residences built since the state's building code was enacted in 1974.

By constrast, Montgomery County requires that the devices be installed in all residences regardless of the age of the building. A similar measure will go into effect in the District of Columbia in 1981.

Fairfax County Supervisor Marie B. Travesky (R-Springfield) said yesterday she plans to introduce a county resolution today calling on insurance companies to require holders of fire insurance policies to install smoke detectors.

"We've just got to make people realize that this is a life-saving device," said Travesky, adding that she had equipped her own home with detectors after an acquaintance had been killed ina risidential fire.