Some residents of I Street NW say George Washington University's need for a new eight-story medical building will overshadow something very important to them: their living room windows.

"Our concern is that sunlight into the units that face west will be blocked entirely if this building is built," said James T. Draude, head of the residents association of The President condominium. "It's too high, and it's too big."

The university last month unveiled plans to erect the building at 22nd and I streets NW, said Charles E. Diehl, GWU vice president and treasurer. The 156,000-square-foot structure would be an addition to the neighboring H. B. Burns Building at 2150 Pennsylvania Ave. and would house the George Washington University Health Maintanence Organization, now in a rented building at 25th and M streets NW.

Diehl said a five-year lease for the M Street building will expire in December 1986 and the building's owners want the HMO to vacate.

"We have been planning a new building actively for over a year," he said. "We have a need for new HMO space and a need to expand the Burns Building to provide adequate teaching and research space for our students and faculty."

The university has applied to the District's Board of Zoning Appeals for a special exception permit for the new building, said Diehl. He said all schools located in residential areas in the District need special exceptions for construction.

However, the District already has approved a master plan that the University submitted in the early 1960s and updates periodically. Diehl said George Washington's approved master plan indicates the university always has planned to construct a building on the I Street site, which is now a parking lot.

"We are not doing anything that we haven't said for years that we were going to do," Diehl said.

Residents of The President, the only residential building in the neighborhood not owned by the university, say they are not opposed to every building proposal -- just this one. They say it will be 40 feet higher than their eight-story building and will block the views and sunshine.

This week the board of directors of the 75-unit condominium voted to hire a lawyer to pursue ways they can legally stop the construction, and residents are planning to attend a Board of Zoning Appeals hearing on the new building scheduled for late February.

Diehl said GW is "looking into laws that prohibit new buildings from blocking the light of existing buildings." However, District officials said the city does not have "sunshine laws," as they are called.

Diehl said the university has taken pains to design a building that will be as unobtrusive as possible. He said GW has the legal right to build up to the existing condominium, blocking out its windows entirely, but decided instead to push the building back from the property line to save the view.

"We've tried to accommodate our neighbors as much as possible," Diehl said. "We can't not build the building. . . . We would not be building if we did not need it."