June electric bills will be $5 to $10 more per 1,000 kilowatt hours (kwh) than last month because of the switch to the more expensive summer rate schedules. Anyone using air conditioning on a regular basis will pay more than that.

The higher prices for the Washington area's hottest months are intended to encourage conservation and hold down customer power use. Ultimately, that can help consumers--and minimize their monthly electric bills--by reducing company operating expenses and expansion needs.

But the immediate effect is that the public pays a higher price for power.

Actual bills vary widely, based on where a home is and how much electricity is used and whether the supplier is Potomac Electric Power Co. or Virginia Electric and Power Co.

In general, however, here is what the average consumer can expect to find on the next statement:

* District residential customers using an average of 1,000 kwh a month will pay $75.13 in June, excluding fuel adjustments and local taxes, compared with $65.29 last month.

The charge for summer power jumps when customer use exceeds 400 kwh during the month, increasing from 7.163 cents per kwh in winter to 8.804 cents per kwh in summer--a difference that adds $9.84 to the bill for 1,000 kwh.

A breakdown of the $75.13 summer bill looks like this: $2.25 for customer charge and first 30 kwh; $20.06 for 370 kwh; and $52.82 (rather than $42.98) for the remaining 600 kwh. Fuel adjustment fees can vary from month to month in the District; last month, D.C. customers received a credit of $1.87 per 1,000 kilowatt hours used.

* Maryland residential customers using an average of 1,000 kwh a month will pay $72.43 in June, excluding local taxes, compared with $67.47 last month.

The summer price increases when customer use exceeds 750 kwh during the month. During winter, Pepco charges 4.728 cents for the first 750 kwh used by a residential customer each month and drops the price to 2.744 cents per kwh for the remaining power used. But in summer the kwh price of 4.728 cents never changes. A breakdown of the $72.43 summer bill includes: $3 customer charge, $47.28 for 1,000 kwh (rather than the winter price of $42.32), and $22.15 for the fuel charge.

* Virginia residential customers of Pepco using an average of 1,000 kwh a month will pay $76.71 in June, excluding local taxes, compared with $66.87 last month.

The summer price increases when customer use exceeds 200 kwh during the month. In winter, Pepco charges 4.712 cents per kwh for the first 200 kwh used by a residential customer each month and then drops the price to 3.482 cents per kwh. But in summer the kwh price remains the same. A breakdown of the $76.71 summer bill includes: $4.80 for the customer charge, $47.11 for the 1,000 kwh (rather than $37.27 in winter) and $24.80 for the fuel adjustment charge.

Virginia residential customers of Vepco using an average of 1,000 kwh a month will pay $74.48 in June, excluding local taxes, compared with $69.84 last month.

The summer price increases when customer use exceeds 800 kwh during the month. Throughout the year, Vepco charges 6.734 cents per kwh for the first 800 kwh used by the customer each month. But in winter the company's price drops to 5.236 cents per kwh after the first 800 kwh; in summer, the Vepco price goes up to 7.553 cents per kwh after the first 800 kwh. A breakdown of the $74.48 summer bill includes: $5.50 customer charge and $68.98 for the 1,000 kwh (rather than the winter charge of $64.34).

Pepco started applying the higher summer rates to customer accounts on May 22, according to company representative Nancy Moses. Customers whose meters were read since then would receive June bills based on the summer rate schedule, she said. The summer schedule will be used until Oct. 24, she said.

Vepco summer rates went into effect with meters read June 1 and will remain until Sept. 30, spokesman Dennis Hedsepeth said.