Aug 8 (Reuters) - Utility firm NRG Energy ( NRG ) posted

a near 148% jump in second-quarter profit on Thursday, helped by

lower costs and resilient demand for power during peak summer

months.

NRG also said it entered into an agreement to sell its

Airton HVAC business for $500 million. The company did not

disclose details of the deal, which is expected to close by the

end of the year.

Shares of the company were up 1.5% before the bell.

Demand for natural gas to power cooling appliances increased

during the April-June quarter, as customers cranked up their air

conditioners and refrigerators to deal with the record-breaking

hot temperatures.

The company's operating expenses fell nearly 10% to $5.25

billion, while revenue rose to $6.66 billion in the quarter

ended June 30, from $6.35 billion last year.

The company said its core profit came in at $935 million,

boosted primarily by margin growth from power and natural gas

and improvement in customer counts.

Analysts were expecting NRG to report a core profit of

$891.9 million for the second quarter, according to LSEG data.

The Houston, Texas-based firm said its net income jumped to

$721 million, or $3.37 per share, in the second quarter from

$291 million, or $1.25 per share, a year earlier.