LET THE SUN SHINE IN! In summer or snow a solar greenhouse brings light and warmth to a home

WHEN Hurricane Gloria came barreling up the East Coast on a direct course for New England a year ago, Norman Flanders hastily boarded up the gaping hole he'd cut in the side of his house and waited, wondering if the planned remodeling would turn into wholesale reconstruction. He needn't have worried; the boards held firm and the setback was only temporary. Little more than a week later, the solarium he had long wanted was in place and complete.

By adding (under somewhat dramatic circumstances) an attached greenhouse to their dining room, Norm and Eleanor Flanders converted it into a sun room that has had an equally dramatic impact on their life style. The room, they say, draws exclamations from first-time visitors as soon as they walk in.

``Eating isn't just eating anymore,'' says Mrs. Flanders, ``it's a dining experience.''

She talks, too, of being out in the falling snow ``without being in it,'' of being ``in the rain without getting wet,'' and most of all, of ``being bathed in the warm, warm sun'' when icicles hang from the eves.

Like vast numbers of Americans, who last year spent some $62 billion remodeling their homes, Mr. and Mrs. Flanders decided that improving their present home made far more sense than moving or building new; like increasing numbers, too, they opted for a solar addition to their home, rather than just adding a conventional room. Industry sources say that 100,000 new solariums, ranging in price from $5,000 to $20,000, were added to private homes in 1985.

These sun rooms are also popping up on restaurants, banks, hotels, and office buildings.

``It [the sun room] is still a unique feature,'' says Bill Purdie of New Hampshire Glass, the company that erected the Flanders's sun room. ``But the way it's going it will become standard equipment.''

Why the growing popularity of sun rooms?

According to Diane Boas, editor of the 1986 edition of Greenhouses for Living, public interest was sparked by the energy crisis of the 1970s. People began attaching conventional lean-to greenhouses -- a far cry from the modern sun room -- onto the south-facing sides of their homes to tap the sun's heat and pump ``free'' Btus into the house.

They worked well, Ms. Boas points out, but soon engineers designed even more efficient heat-trapping and heat-holding devices.

Later, architects and interior designers contributed their expertise and turned greenhouses from mere solar collectors into attractive living areas.

Today, with home heating costs down, the accent is on living space.

``We're selling the feel of the outdoors and bringing it in,'' says Chris Esposito, who 10 years ago founded Four Season's Greenhouses, and has since turned it into the largest of the nation's more than 50 sun room manufacturing companies.

Jack Chellis, a Portland, Maine dealer for the Gardenway laminated-beam sun room, says: ``We sell an enhanced life style. The sun room can be any room you want it to be -- the dining room, the living room, the family room, the exercise room, even the bathroom if you're sure of your privacy.''

Restaurants were the first commercial enterprises to capitalize on man's love of the sun in this way.

``The battle lines have been drawn'' was the way the Chicago Tribune described the haste with which restaurants in the region were adding sun spaces and atriums in a campaign of one-upmanship last year.

In Burlington, Vt., the addition of a sun space to a former coffee shop converted it into one of the more popular restaurants in the region.

Tables in the atrium ``are the first to fill up,'' say the staff of Chutes Eatery. The trend is similar around the country, according to Ms. Boas. Whether you stop along the highway for a quick burger at a fast-food chain or choose an elegant evening out, ``you now have many opportunities to enjoy a culinary experience in a sun space,'' she says.

If restaurants took their cue orignally from residential sun spaces, they in turn are sparking continued homeowner interest. Many people ``get the feel and the sense of a sun space after a restaurant in the region adds one,'' Boas notes.

When considering a sun room addition, Jack Chellis suggests people start by asking themselves a lot of questions: What's the room for? Is it primarily a space heater, a living space, or both? Who will use it and how often? Will it be a winter-only room or one that's used year round? Will it be used primarily in the morning or afternoon?

``It's no use wanting a sun room for a breakfast nook and then placing it where there is no sun in the morning and the sun streams in all afternnon,'' Mr. Chellis says. Most important, will you be able to place the greenhouse on the sunny (south) side of the house?

If the side with the view is on the north, ``that's still OK,'' he says, as long as you realize that ``you will have to heat it, it will never heat you.''

Once you have the answers to these questions, go to dealers in your area and give them the information.

``Better still,'' says Chellis, ``don't say a word. Let the dealer ask the questions. If he asks many probing ones, you've probably got one who knows what he's doing.''

Another option for would-be sun room owners is to get a copy of the 1986 directory from Greenhouses for Living ($9.50 plus postage), 350 Fifth Ave, New York, NY 10001. The directory was started by a group of architects who realized that there was a need for basic information on this rapidly expanding industry. It is the only resource of its kind in the United States.