VICTORIANS understood that proper windows start at the floor and stop at the ceiling. Such windows follow the sun's path to lavish its light on big pots of palms and on pleased people.

From the outside, the Robert Edmund Lee house in Georgetown seems to be a vintage Victorian. Its tall skinny windows promise high ceilings and bright rooms. But when you walk through the heavy, solid-wood double front doors, you discover that, like other Victorians, it has a secret inner life, far more dramatic than its formally correct street side would lead you to believe.

The ceiling of the hall, though that's too pallid a word for it, soars two stories up to a glass roof. Tall camellias, blooming red at Christmas, and giant umbrella trees, spreading generous leaves, live in squares of earth, mulched with round river stones. Azaleas in great wood barrels flower for Valentine's Day. The floor is large stone rectangles so there's no worry about water overflowing saucers. To provide that water, there's even a faucet and a hose.

The hall is a true traditional center hall, because it goes through the house to the garden. Its far wall is all glass, framed in black metal, to reveal a garden as spectacular as the house. A sweep of the same stone paving goes to a twenty-by-thirty-foot raised lily pond, the lowest of three terraces carved from a steep hillside. Lilies bloom here until frost and begin again in early spring. In late summer, the vivid tropic varieties are hard to believe.

In the winter, the lily pond sometimes freezes over, but even in the last winter, only six of ninety-eight fish were lost. On one side of the pool, stones cantilever out to provide a waterfall. On the other side, cantilvered stones go up to the middle terrace, and from there to the highest. Once there was a hedge of magnolias but the cold killed all twelve so now there are cedars. Lester Collins planned the garden and William Moeller, who more often builds swimming pools, did the lily pond.

Garden, greenhouse and house were all designed by Hugh Newell Jacobsen almost sixteen years ago. The two-story garden room with glass roof has since been copied time and again by other architects as a way to bring the sun into a row house.

Phyllis Lee didn't really have all that in mind when she first called in Jacobsen. "I just wanted a good-sized dining room and perhaps a green-house, if it could be tucked away unobtrusively. We started with an extra lot as well as the house, which suffered all sorts of changes to its original Victorian self. When Hugh saw it, he stood there for a moment and then came up with the whole scheme."

What Jacobsen did was to design an entire duplicate two-room, two-story house, linked to the old by the glass room, with a bridge at second-floor level. In the new section is a large living room extending from the front building line to the back garden. Upstairs is the same size master bedroom and bath. Both rooms have splendid views of the lily pond, through tall, slender windows. On the street side, more tall windows bring in the south sun to both rooms.

The south front windows are actually Jacobsen-Victorian. The old house's original windows had long been junked up. There was quite a to-do with the Fine Arts Commission about the new tall skinny windows with their unmuntined glass. Finally the Lees had to stick snap-on muntins on their nice windows to get the design approved. But then, Georgetown wan't as familiar with Jacobsenian remodelings then.

In the old house, walls were taken down and passages rerouted to provide a library where the entry hall once was. Oh yes, Mrs. Lee got her pleasant dining room with a view to the garden and space for the elegant Biedermeyer dining chairs. The earlier kitchen with its raised fireplace and door to the garden is much the same as it was, only with a wall of cabinets.

Lee, once a journalist, was, before he retired, head of State Department Congressional Relations, so the terrace often serves dinner for sixty. Mrs. Lee meanwhile complains that the most showy of the lilies go to bed at noon and the others open only at 10 p.m.

the Lees have spent almost half their time in Ireland for the past eight years. But now they've sold the Irish house, and are avoiding foreign entanglements, to give their full fidelity to their Georgetown glasshouse. They've re-covered the living room sofas and will be around to watch the camellia bloom for Christmas and the azaleas for Valentine's Day in their winter garden.