For the first time in its 62-year history, the Phillips Collection is planning to close. Director Laughlin Phillips yesterday confirmed rumors that the museum hopes to shut down for six months, starting in June, for renovations. The project is contingent on working out "financing details," he said.

The closing will be bad news for Washington art lovers. "But anything that makes the collection safer is good news in the long run," said Phillips. "It's a project that can no longer be put off."

The planned $2 million renovation is phase one of a $3.5 million two-part scheme to bring the Phillips' aging plant up to date, and involves only the red brick Georgian Revival house built as the Phillips family residence in 1897. In 1921, Duncan and Marjorie Phillips opened the building to the public as the first museum of modern art in America.

Except for the addition of a third floor to the music room wing for office space, the renovations will be interior in this first phase. The project was designed by the architectural firm of Arthur Cotton Moore Associates. It will include installation of climate control and security systems, complete rewiring, an area for lectures and seminars and a modest tearoom and catering facility in the basement.

"It is absolutely mandatory that we get this work done as soon as possible," said Phillips. "The wiring is a Rube Goldberg kind of situation, with exposed wires and some buried in the walls, and it worries us. We don't want to take any chances. Also, we use window air conditioners and steam heat radiators, and humidity can drop abruptly. The lack of proper climate control all these years has taken its toll on our paintings."

Said architect Arthur Cotton Moore: "The changes will be nearly invisible, so that the Phillips can continue to offer a unique way of seeing art in a residential setting, in contrast to other museums in Washington and everywhere. We've gone to a great deal of trouble to make them invisible."

According to the plan, the museum would close on June 14 to allow packing of 75 major paintings--including Renoir's "Luncheon of the Boating Party"--and 18 drawings headed for a two-city tour of Japan. Plans are also underway to exhibit "important" paintings at Garfinckel's downtown department store and in smaller shows at George Washington University and the University of the District of Columbia.

"It's still iffy," said Phillips, "and discussions have centered on how to provide museum-level security in the store. But I'm confident it can be done." The Phillips show in Tokyo also will be shown in a department store setting, a standard procedure in Japan. "Most of our best paintings will be on view somewhere, including loans to other American museums," said Phillips.

He said there will be no staff reduction during the closing, and that the museum guards will be used to supplement security for the satellite shows.

The closing comes following a number of efforts to find at least $5 million in funding, including:

The rental to five American museums of 75 masterpieces from the collection, which raised $750,000 in fees and catalogue royalties.

Offering to name galleries, a conservation laboratory, offices, storerooms, and concerts in its Sunday-afternoon series of chamber-music presentations after donors. A gallery naming, Phillips said, would require a donation of at least $200,000.

Offering the use of the Phillips for social events to corporations in exchange for contributions.

The upcoming $200,000 rental of paintings for the Japanese tour, which is sponsored by a Japanese newspaper.

Phillips said that neither the closing nor the means of raising the $1 million still needed for phase one have been formally approved by the museum's board of trustees.

"There are all sorts of options for borrowing money. One alternative we're exploring is a tax-exempt revenue bond, and we've had preliminary talks with District officials about it. The Chicago Art Institute, the Boston Museum of Fine Arts and George Washington University have done it, but it's a relatively new form of funding for museums.

"There is a kind of master plan at work here, but there are some unresolved problems," said Phillips. "One of them is the fact that when the original $5 million fund drive was launched two years ago, it was thought that $2 million would cover the cost of renovations both to the old and newer buildings. Phase two of our building program--involving changes in the newer 1959 building--had to be postponed because we realized the renovation of the old building would be more complicated than expected. Instead of just installing climate control and conveniences--like an elevator--it turned out that to conform to the fire code, we have to tear up every wall in the place to install new wiring, which increased the expense considerably.

"We had thought the $2 million would cover all the renovations. It turns out that renovations in the old building will cost that much alone, by the time we replace this very old furniture and get some new rugs on the floor."

This will be the fifth major change to the Georgian Revival house, which was built by the firm of Hornblower & Marshall in 1897 for the Phillips family. In 1907, a T-shaped, one-story wing was added to serve as a music room--still the setting for popular Sunday afternoon concerts. In 1920, when the private collection was about to open to the public, a large gallery was built above it, designed by McKim, Mead & White. Moore's plan adds a third layer to that addition.

In 1959, a limestone building designed by George Rowe was opened as the new wing of the original building, to which it is attached by a steel and glass bridge. Phase two of the Phillips master plan calls for extensive changes to both the interior and exterior of this building, and will cost an additional $1.5 million, also not yet funded. The second phase would replace the sculpture garden with a small wing, which would house a conservation lab and provide urgently needed storage space. Many works are now stored in closets and bathrooms.