Lowe's Cos missed quarterly profit and sales estimates as benefits from the homebuyer tax credit and cash for appliances programs waned, and the retailer warned of uncertain demand.

The second-largest home improvement chain after Home Depot also forecast current-quarter profit of 28 cents to 32 cents a share, while analysts were expecting 31 cents.

Sales at Lowe's and Home Depot had benefited immensely in the first quarter, which ended in April. Many who put off renovations during the recession upgraded appliances to take advantage of a federal stimulus for energy-efficient goods, while others tried to take advantage of the first-time homebuyer tax credit.

Net income at Lowe's rose to $832 million, or 58 cents a share, in the second quarter ended July 30 from $759 million, or 51 cents a share, a year earlier.

Analysts on average were expecting 59 cents a share, according to Thomson Reuters I/B/E/S.

Sales rose 3.8 percent to $14.36 billion, but missed the average estimate of $14.52 billion.

Lowe's said it expected a sales increase of 3 percent to 5 percent in the third quarter.

Shares of Lowe's were up 1.1 percent at $19.81 in trading before the market opened.

(Reporting by Dhanya Skariachan; Editing by Lisa Von Ahn)