A proposal to convert President Carter's home insulation program from being voluntary to mandatory in 1985 has been drafted by House Democrats who believe they have the votes to write it into the omnibus energy bill.

The House Commerce subcommittee handling most nontax parts of the President's energy package intends to vote on the insulation plan today.Before beginning 2 1/2 weeks of voting on issues including natural gas price regulation, subcommittee Democrats had breakfast with Carter and came away saying he hoped they could strengthen his bill without endorsing specific changes.

The administration has said that if voluntary home insulation encouraged by tax credits did not achieve the goal of insulating 90 per cent of the nation's residences by 1985 it would ask that the insulation be required by law.

A new draft of the home insulation section put together by Subcommittee Chairman John D. Dingell (D-Mich.), some other Democrats and staff, which makes several substantive changes in the adminsitration's proposal, was put before the subcommittee as it began its markup sessions yesterday.

It includes a provision that after Jan. 1, 1985 no federally insured lending institution could make a housing loan for purchase of a residence that did not meet insulation standards to be set. This would cover virtually all sources of mortgage money and cover the sale of old and new houses.

As sent to Congress by the President, the insulation section simply required that local utility companies advise customers on the benefits of insulation, offer to make or arrange insulation loans that could be repaid as part of monthly utility bills and either install insulation or give customer a list of local contractors who could. The proposal to give a tax credit of up to $410 to encourage home insulation is before the Ways and Means Committee.

Tdraft that the subcommittee will be working from today would, in addition to making insulation mandatory in eight years:

Forbid utilities from installing insulation in homes.

Extend coverage to condominiums, cooperatives and apartments, adding 22 million units to the 40 million single-family homes covered by the bill.

Require that federal energy officials consult with the Federal Trade Commission to set standards to prevent anti-competitive practices in the insulation business.

Rep. Andrew Maguire (D.N.J.) said he will offer an amendment to make the insulation program mandatory three years earlier in 1982.

Dingell's subcommittee feels in a time bind because of the House Democratic leadership's hope to push the bill through the House before the August recess. After three weeks of hearings, Dingell now has scheduled 12 days of voting in subcommittee and then approval by the parent Commerce Committee by July 13. He said he had asked the leadership for more time but was turned down.

The new insulation section was printed Wednesday night and first seen by committee Republicans at 10:15 a.m. yesterday. They tried to adjourn until today to have time to read the 19-page draft but lost, 11 to 7. Then the subcommittee adjourned for the day before lunch without taking any important votes in order to take part in House debate on the bill to create a department of energy.