The administrator of a Montgomery County nursing and retirement home says his organization may have to abandon a proposed expansion because of delays in getting government approval of a solar energy heating plan.

The Carter administration is placing emphasis on the future use of solar energy as an alternative power source and has called for the installation of solar energy devices in 2.5 million homes by 1985.

But the Farmers Home Administration, an Agriculture Department agency which makes low-interest loans for construction rural areas, has been reluctant to approve such a system for Friends House in Sandy Spring - and for other applicants - because it feels that solar energy is still in the experimental stage.

Robert Mills, executive director of the five-year-old, Quaker-run home, said he has been trying for five months to convince the farm agency that the system is feasible. Now, he says, inflation in building costs during that period may put a halt to the home's plans for a 50-bed expansion.

Last week, FmHA told Friends House that, under nursing home construction regulations of the Department of Health, Education and Welfare, the solar heating unit would have to be an auxiliary to a standard heating system.

HEW requirements call for a system consisting of a primary furnace capable of furnishing 100 per cent of the nursing home's heating needs and a back-up furnace capable of suppling 70 per cent of the heating needs if the first systme fails.

The solar unit cannot replace either of these furnace, HEW engineers had told the project's architect, McNeill Baker, of Edmunds and Hyde in Baltimore. But last Monday HEW softened that stand, telling Baker that under certain circumstances, a waiver could be granted.

The solar system Friends House proposed would provide about 50 per cent of the nursing home's heating needs, and would be augmented by an oil furnace capable of providing 100 per cent of the heating needs. But this dual system doesn't qualify for the waiver, Baker was told. Friends House will still have to install a second oil furnace at an additional cost of $10,000, he said.

This extra expense may raise the costs beyond what Friends House can afford, Mills said.

The Friends Home solar plan calls for rooftop panels of corrugated steel covered with glass. Air heated here would be blown into the ventilating system to heat the building.

The home's administration was counting on the solar system as way of cutting its energy costs, according to Mills. "With Medicaid and Medicare, the income is not high, so we have to keep (operating) costs down," he said.

Initial cost estimates for the expansion were $1.2 million, including $62,000 for the solar heating system. Friends House had hoped to begin construction last February.

Since then, projected costs have gone up by $300,000, with steel prices alone rising $20,000 in the last four weeks, the home spokesman said.

he Quaker organization has been granted $625,000 toward the expansion by the Maryland Comprehensive Planning Agency, which approved the use of its funds for solar heating system.

The planning agency had asked FmHa for a $500,000 loan.

But Mills said the agency's chief of community programs for Maryland, John Balsam, told him FmHa could not participate in the project because it proposed to use a solar energy system.

"If you're going to use our money," Mills said he was told, "take the solar out (of the plans)."

When Mills appealed to Sen. Charles Mathias (R-Md.), Mathias commented that it was "an obvious example of the right hand not knowing what the left hand is doing . . . or at least what it's supposed to be doing."

At Mathias' urging, the farm agency reconsidered the proposal and told the nursing home the solar system could be built - but said the money would have to be obtained from a government agency that specializes in "experimental projects," such as the Energy Research and Development Administration.

The home's architect says that when the Friends Home offered to try to raise the money through the church, the farm agency replied that if the home could tap the Quakers for funds for a solar heating system, it probably had access to too much money to qualify for a federal loan.

Mathias said he was "really shocked there is such reluctance on the part of government agencies to take the minimal risks that are involved" in such a project.

At a meeting in Mathias' office in early June, attended by officials of FmHA, Mills the architects, and the engineers, FmHA agreed to permit the use of their funds for the solar heating system if the architects and engineers could show the plan was cost-effective.

Baker said he told FmHA the solar system would "pay for itself in less than 20 years . . . but they wanted verification."

Mills said he thinks one reason for FmHA's reluctance to make their loan is a fear of setting a precedent.

The Senate Rural Development Subcommittee has requested testimony from the Agriculture Department about its energy programs and policies at hearings later this month.