Where does the talk stop and the action start when it comes to our costly energy crisis? One place is Manchester, N.H., where the General Services Administration is operating a new $8.7 million, "energy efficient" office building.

GSA, landlord for some 10,000 federal buildings, is using the Norris Cotton Building in Manchester as a laboratory to test energy conservation technology, and considers it the first in a new generation of energy-conserving buildings.

At the very least, it is the first federal building built from the ground up with energy efficiency in mind. And it will be the first to be throughly monitored for its energy comsumption by the National Bureau of Standards. It is hoped that the results of the monitoring, funded by the Energy Research and Development Administration, will aid architects and engineers in the future design of energy-efficient public buildings.

The building was conceived as any energy conservation pilot project in 1972. GSA assembled a team of experienced architects, engineers and consultants who used a sophisticated computer program developed at NBS to study more than three dozen design options.

From the computer studies it was estimated that the building could be use at lease one-third less energy than conventional structures of comparable size.

While they made no real break-throughs, the designers drew on dozens of energy-conserving features that were already available commerically but had not been tested as a complete package.

One of the building's most striking features is its nearly cubical shape. This minimizes exterior surfaces areas, the greatest sources of heat loss for a building - especially in a northern city such as Manchester. The window areas are aldo smaller than those of conventional buildings and are limited to the east, west, and southern exposures. Windows are also closer to the ceiling, taking full advantage of natural daylight. In addition, they are double-glazed and designed to limit air leakage and heat transfer.

The north wall is windowless and elevators, storage closets, and bathrooms have been placed there, acting as additional insulation for the rest of the building and protecting it against the large heat loss normally found on a northern facade.

The building's shell also has a heavier wall construction to minimize the effects of outdoor temperature and other changes in the weather.

Madeleine Jacobs is a public information specialist at the National Bureau of Standards and co-author of an energy conservation booklet for homeowners, "Making the Most of Your Energy Dollars in Home Heating and Cooling."