NOTE 13. WARRANTIES

Provisions of our sales agreements include product warranties customary to these types of agreements, ranging from 18 months to 24 months following installation for the Thin Films SBU and 5 years to 10 years following installation for the Solar Energy SBU. Customers of our Solar Energy SBU have the option to purchase extended warranties up to 20 years. Our provision for the estimated cost of warranties is recorded when revenue is recognized. Our warranty provision is based on historical experience by product, configuration and geographic region.

Accruals are established for warranty issues that are probable to result in future costs. Changes in accrued product warranties for the three months and nine months ended September 30, 2011 and 2010, including those acquired on May 3, 2010 as part of the PV Powered acquisition, were as follows (in thousands):


	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2011			2010			2011			2010

Balances at beginning of period	$	14,296		$	11,179		$	12,949		$	6,978
Warranty liabilities acquired		—			—			—			1,546
Increases to accruals related to sales during the period		2,498			3,441			7,542			8,089
Warranty expenditures		(2,073	)		(2,558	)		(5,770	)		(4,551	)

Balances at end of period	$	14,721		$	12,062		$	14,721		$	12,062