Ameresco, Inc. Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Changes in the allowance for credit losses was as follows:


	Year Ended December 31,
	2020		2019		2018
Allowance for credit loss, beginning of period	$	2,260	$	2,765	$	3,315
Charges to (recoveries of) costs and expenses, net	282		(216)		610
Account write-offs and other	(276)		(289)		(1,160)
Allowance for credit loss, end of period	$	2,266	$	2,260	$	2,765

Depreciation and amortization of property and equipment are computed on a straight-line basis over the following estimated useful lives:


Asset Classification						Estimated Useful Life
Furniture and office equipment						Five years
Computer equipment and software costs						Three to five years
Leasehold improvements						Lesser of term of lease or five years
Automobiles						Five years
Land						Unlimited

Property and equipment, net consisted of the following:


	December 31,
	2020		2019
Furniture and office equipment	$	2,905	$	6,108
Computer equipment and software costs	14,531		27,380
Leasehold improvements	2,373		4,062
Automobiles	1,268		1,995
Land	3,041		2,991
Property and equipment, gross	24,118		42,536
Less: accumulated depreciation	(15,136)		(32,432)
Property and equipment, net	$	8,982	$	10,104

The following table sets forth our depreciation expense on property and equipment:


	Year Ended December 31,
Location	2020		2019		2018
Selling, general & administrative expenses	$	3,317	$	2,987	$	2,167