Moving into a new house can be traumatic if everything doesn't work just right, so it's not surprising that the National Endowment for the Humanities had a few complaints about its new office space at 12th Street and Pennsylvania Avenue NW.

In the entrance door to a men's room on the third floor, a one-way window was installed backwards--people outside could see into the rest room but people on the inside could see only what appeared to be a mirror.

In various parts of the majestic, refurbished old Post Office building, indoor temperatures in April plummeted to near freezing as uncharacteristically chilly spring winds swept through the city.

The self-contained modular system furniture--a center of controversy for years--proved that the self-contained lighting systems were as inadequate as their critics contended. Endowment officials are already calculating how much they'll have to spend on supplemental lighting.

The problems in the building were so extensive that the Endowment's public affairs staff this month chose to devote two pages in its in-house newsletter, Insight, to the topic. In that article, administrative officials levied a barrage of complaints against the General Services Administration, which owns and operates the building.

For example, Bob Stock, an Endowment administrative services officer, told Insight the heating problems were significant.

"We do not have a systematic process at this point by which the GSA field office can address this problem," said Stock, who happens to be a former GSA building manager. He is quoted as saying: "No one has called me from GSA, for example, to ask if the building is comfortable. I think that such a call could reasonably have been expected within the first six days of a move into a facility such as this; a building that they are, in part, responsible for."

Stock refused to be interviewed and his boss, director of administration Victor Loughnan, said the response to the tone of the article is being blown "way out of proportion." He would not say, however, that either he or Stock was misquoted.

"These problems would be a concern down the road much more so than they are now if they persist," said Marion Blakey, the Endowment's director of public affairs, and the supervisor of the "Insight" newsletter. "We feel we accurately depicted the situation."

Blakey said the lighting problems in the office are obvious. "I'm in a dark office now and I could use another light," she said. In a systems furniture set-up, you can't add a floor or table lamp, since all the lighting systems are attached to the furniture or are massive free-standing kiosks.

"I'm sorry they feel that way," said James G. Whitlock, GSA's regional public buildings commissioner. "We are bending over backwards to put this building in shape and we think we've done an excellent job."

In 1972, the federal government decided that federal buildings that were predominantly used by the U.S. Post Office should be given--free of charge--to the then-new, quasi-governmental U.S. Postal Service. Now, with congressional approval, the federal taxpayer is buying back one of those buildings, in Pittsburgh, for a pretty penny: more than $23 million.

Negotiations are now hung up because the $23.5 million appraisal drawn up by GSA in 1981 is several million dollars short of the USPS appraisal drawn up a year later. The deal is supposed to be worked out within a month.

For the past 49 years, the building has housed federal agencies, the U.S. courts and the postal service in the downtown area. After buying the building, GSA will spend about $9.7 million to renovate the 220,000 square feet of useable office space. Dale Gottschalk, GSA's repair and alterations chief, said that most of the 888 federal employes housed in 19 leased locations throughout the area will be consolidated by fiscal 1986--the exceptions will be small offices that have to be out in the community, like Social Security storefronts.

Blake Construction Co. has submitted the low bid on the joint Smithsonian Institution-GSA project to build an underground museum behind the "Castle." Blake's bid was $39.38 million for the Quadrangle project, which underbid a North Carolina company by more than $3.5 million.