BIG FURNITURE

''WE'VE got to use the airspace these days,'' says David C. Ogren, president of the Singer Furniture Company. He isn't speaking of the space over buildings, but the space above furniture.

He is trying to explain why so many pieces of furniture are now getting taller, wider, and bigger. They simply have to do more, store more, and perform better, he emphasizes, speaking at a recent Southern Furniture Market.

''People look at furniture today,'' Mr. Ogren continues, ''and ask what all it will do for them. They don't settle for looks. They want lots of built-in convenience. They want pieces that will fit equally well in many rooms of the house and move easily on to the next one.''

The furniture required to serve a multitude of purposes comes in many new heights, sizes, and names. Suddenly we have dressing chests, chest/-dressers, tall dressers (42 inches high), oversize cabinets, and wardrobe armoires with drawers, trays, removable hanging rods, and adjustable shelves.

''Armoires, chests, and entire walls of correlated units are being designed to pack as many purposes as possible into individual pieces,'' says Renee Martin Smith, an interior designer with Drexel Heritage. ''The primary need in smaller rooms is to make the best possible use of wall spaces and to help people organize and control their belongings.''

Leslie Flippo, vice-president of Hickory Furniture Company, comments: ''Bedrooms are obviously getting smaller, but people love king-size and queen-size beds, which take up a lot of square footage. So where do they store their possessions? I think we'll be seeing more armoires in bedrooms, even two armoires - his and her versions.''

''Also,'' he continues, ''because it is now standard to have television, stereo, or VCRs in the bedroom, we must provide storage space for electronics as well as for clothing. Again, this fact argues for the reentrance of big wardrobes or armoires into the bedroom. Where better to conceal the high-tech stuff?''

Arcadia, a new furniture group created by Bernhardt Industries especially for apartments and condominiums, includes an adaptable door chest with removable shelf and partitions, plus knock-out plugs to facilitate installation of TV or sound equipment.

Robert M. Clark, president of Boyd, a Long Beach, Calif., company, brought his new oiled-oak Foxrun collection to the Southern market. ''Our approach to design,'' he explains, ''is to meet the needs of today's casual life style and to offer lots of function. The big, roomy campaign chest in this group has hanging space and optional shelves on the left side and seven deep drawers on the right side.''

In the same vein is Conant Ball Company's master chest in solid oak. Shelves and drawers offer plenty of storage space.