UPDATE 1-Lowe's questioned over Connecticut taxes -AG

(Adds company response)

NEW YORK Nov 18 (Reuters) - Connecticut's attorney general is investigating consumer complaints that Lowe's Cos Inc (LOW.N) improperly charged sales tax on certain energy efficiency products that are exempt under state law.

In a letter to the company's chief executive, Attorney General Richard Blumenthal urged Lowe's to make an immediate audit of its tax charges on exempt items and refund consumers who may have been overcharged, according to a statement from Blumenthal on Wednesday.

Under state law, products ranging from thermostats to fluorescent light bulbs that meet the federal Energy Star standard are exempt from the sales and use tax.

Lowe's, the No. 2 home improvement chain, said it was working with the attorney general's office to resolve the issue and plans to refund the customers who were overcharged.

The company, which blamed the incident on a coding error, said it was aware of only two complaints as of Wednesday evening.

"This is an isolated and inadvertent incident," Lowe's spokeswoman Julie Yenichek said by phone.

In 2006, Blumenthal found that Home Depot Inc (HD.N) collected sales tax on exempt energy conservation products. Home Depot acknowledged the error, citing a computer glitch, and agreed to provide refunds to consumers, the attorney general said.