The Four Seasons Hotel will shut down most of its rooms for a major renovation that will leave the hotel largely out of service for the busy campaign season and next year's presidential inauguration -- and leave it with fewer rooms once the project is done.

The hotel, built in 1978, plans a $20 million renovation of its original 200 rooms, to commence next week. That would keep those rooms out of use until March or April of 2005. A new wing of the hotel, containing 60 rooms and suites, will remain in use through the renovation, as will its restaurant, spa and banquet facilities.

In an unusual move for a hotel renovation, Four Seasons will have fewer rooms when the renovation is completed. Every three existing rooms will be turned into two rooms, increasing a room's typical size from 325 square feet to 525 square feet. General manager Christopher Hunsberger forecasts that rates for standard rooms, now $450 a night, are to rise commensurately. The hotel fetches a $100 premium for rooms of the larger size in the new wing.

A portion of the extra space will be devoted to lavish bathrooms, with more room to move around and custom maple and pear wood cabinetry.

The closing of the Four Seasons rooms presents an opportunity for other high-end Washington hotels to capture some of their regulars, at least for the next nine months. "Having 200 rooms out of inventory, that's a substantial amount that I'm sure will affect the luxury market in the city," said Paul Westbrook, general manager of Washington area Ritz-Carlton hotels.

The timing may be particularly opportune for the Mandarin Oriental, which opened in the spring on the Southwest waterfront and seeks to appeal to the same top-of-the-line market as the Four Seasons and the Ritz, but has a more distant location from the center of Washington. It laid off 40 employees this year during the summer lull in business.

"It should assist us," said David Rothwell, resident manager of the Mandarin. "If they can't stay at the Four Seasons because of the renovation, we'd love to be their second choice and ultimately their first choice."

It may get most hairy during the inauguration, when dignitaries generally arrive in Washington by the thousands. Four Seasons, with just 60 rooms to use during that week, has already sold out to some of its best customers, Hunsberger said.

Even without knowing who will win in November?

"Our customers tend to be coming no matter who wins," he said.

An artist's illustration of a larger room at Four Seasons Hotel. Every three rooms will be turned into two rooms with more space and bigger bathrooms.