The Montgomery County consumer affairs office released yesterday a list of 32 local heating and air-conditioning firms recommended by area residents who said the firms had done good work for them.

The county had worked with the Federal Trade Commission to develop a questionnaire mailed out to 7,500 homeowners in May. A total of 1,250 people responded.

"The idea was to let consumers know which businesses have served them well rather than just say which companies have complaints against them," said Barbara B. Gregg, director of the Montgomery County consumer agency.

"We have good people working for us and we like to think we know what we are doing," said Dennis Hoffacker, owner of the Gaithersburg Air Conditioning & Heating Inc., the firm with the most recommendations. Twenty-five homeowners responding to the survey said that Hoffacker's firm had worked for them and all 25 said they would recommend the company to anyone needing installation or maintenance work done on their heating or cooling units.

The list compiled by the consumer office shows the 32 firms named by five or more consumers. It also shows how many individuals using a firm also recommend it. In addition, the agency has a list of 14 firms that were named and recommended by fewer than five consumers.

Both lists are available at some libraries or by sending a self-addressed, stamped envelope to Heating, Office of Consumer Affairs, 611 Rockville Pike, Rockville, 20852.

FTC attorney Mallory Duncan said officials there are watching to see if the project helps consumers. "We are going to ask consumers to get back to us and tell us if this works," he said.

The $4,000 survey was launched early this year "to see if providing positive information about firms is an effective alternative to traditional law enforcement," the FTC said.

Both federal and local officials said that the list is intended as an additional tool, rather than a replacement, for consumers making decisions about heating and cooling work for their homes. It was not meant to imply that firms omitted from the survey did poor work.

"What we have done up until now is share our complaint records," Gregg said. "We urge people to continue to use this information. And we urge them to shop around, to get estimates, to get contracts in writing.

"But now, in addition to that, we will give people the names of firms that other Montgomery County residents have done business with and will recommend, in the heating and air-conditioning area.

A list of firms named by five or more of the persons who responded to the Montgomery County survey follows:

Gaithersburg Air Conditioning & Heating Inc., Derwood, recommended by 25 of 25 who responded by naming this firm; Academy Heating & Air Conditioning Service, Rockville, recommended by 22 of 23; Davis & Davis Air Conditioning & Heating Co., 21 of 23; B & B Refrigeration & Air Conditioning Service Co., 17 of 24; David B. Fielder, Bethesda, 16 of 16; Aitken Co., Rockville, 14 of 15; Climate Trane Corp., 14 of 19; Metro Fuels Co., Bethesda, 14 of 15; Sears, Roebuck & Co., 12 of 14; Bethesda Refrigeration Service Inc., 11 of 12; Home Air Conditioning Co., Silver Spring, 10 of 12; Parker Heating & Air Conditioning Inc., Rockville, 8 of 11; Washington Gas Co., 8 of 8; Alma Heating & Air Conditioning Service, College Park, 6 of 8.

Also, Andre's Refrigeration Service, Rockville, 6 of 6; Armstrong Oil Co., Laytonsville, 6 of 8; Griffith-Consumers Co., Cheverly, 6 of 7; Wachter & Norwood Inc., Gaithersburg, 6 of 7; Combustioneer, Rockville, 5 of 5; Litchfield Inc., Rockville, 5 of 6; Miller, Rod, Inc., Silver Spring, 5 of 5; Mindte Inc., Rockville, 5 of 5; Montgomery Ward, 5 of 7; Thomas W. Perry Inc., 5 of 9; A-B & A Heating & Air Conditioning Inc., 4 of 5; F. S. Campbell, Bethesda, 4 of 5; General Heating Engineering Co. Inc., Capitol Heights, 4 of 5; Minnick's Inc., Laurel, 4 of 11; Polar Air Conditioning Inc., Rockville, 4 of 5; Robinson's Air Conditioning and Heating Co., Rockville, 4 of 5; Sickler Service, Takoma Park, 4 of 6, and George F. Warner & Co., Bethesda, 4 of 5.