Potomac Electric Power Co. is drawing up plans to offer a home insulation program to its customers in metropolitan Washington, company chairman W. Reid Thompson revealed yesterday.

The Pepco "weatherization" service, similar to the national program endorsed Wednesday night by President Carter in his energy message to Congress, would permit consumers to pay for the insulation in installments with monthly electric bills.

Washington Gas Light Co., another area utility firm, already offers an insulation program which has attracted about 3,300 homeowners to date, spokesman Charles Krautler said.

In his energy message, Carter proposed a tax credit for homeowners of 25 per cent for the first $800 invested in conservation by insulation and 11 per cent of the next $1,400.Or, he said, homeowners should be given the option of a weatherization program that all utilities would be required to offer.

However, one Washington businessman expressed some concern yesterday about the involvement of utilities in contracting with outside firms to insulate their customers' homes.

John W. Hechinger, president of the $80-million-a-year do-it-yourself hardware chain of 17 stores that bears his name, said there should be no preference given to insulation by utilities.

If consumers are given the option of having a contractor do insulation, with long-term financing supplied by the utilities, "there would be a tendency to let the contractor do it," and that could hurt his business, Hechinger stated.

Current revolving charge accounts of the Hechinger Co. would not permit long-term installment payments, but the retail firm is studying the establishment of new home modernization loan programs, possibly with a delayed start for the initial payment.

Pepco's Thompson and other local utility executives, meanwhile, had objections of their own about the Carter plan.

"Generally, it is salutary that a President of the United States has finally made a significant, serious statement on the necessity for a unified and comprehensive national energy policy," Thompson said in an interview.

But he expressed strong disappointment with what he described as "a lack of stress with getting on with (development of) nuclear power. . . it must be done." Thompson said he disagreed totally with Carter's earlier decision to halt the development of fast breeder reactors and reprocessing of nuclear fuel. "Coal can't get the job done alone," the Pepco chief executive added.

Thompson also called on the goverment to use some of the funds it collects from energy taxation for more extensive research and development of energy resources and as aid to the utility industry in financing the construction of new plants and conversion of oil-or gas-fired generating stations for use of coal - estimated at $50 billion for completion by 1985.

"That's an almost impossible task. . . it seems virtually impossible" to convert all such plants, he stated.

Pepco, meanwhile, reported a slightings totaled $16.6 million (35 cents a increase in first-quarter profits. Earnshare) in the January-March period compared with $15.5 million (33 cents) a year earlier as revenues climbed to $145 million from $123 million. Directors declared a regular dividend of 32 cents a share, payable June 30 to owners of record May 27.