Summary of Significant Accounting Policies	6 Months Ended
Jun. 30, 2016
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation These interim statements should be read in conjunction with the historical Consolidated Financial Statements and related notes of Comfort Systems included in the Annual Report on Form 10-K as filed with the Securities and Exchange Commission (“SEC”) for the year ended December 31, 2015 (the “Form 10-K”). The accompanying unaudited consolidated financial statements were prepared using generally accepted accounting principles for interim financial information and the instructions to Form 10-Q and applicable rules of Regulation S-X of the SEC. Accordingly, these financial statements do not include all the footnotes required by generally accepted accounting principles for complete financial statements and should be read in conjunction with the Form 10-K. We believe all adjustments necessary for a fair presentation of these interim statements have been included and are of a normal and recurring nature. Certain amounts in prior periods may have been reclassified to conform to the current year presentation. The effects of the reclassifications were not material to the unaudited consolidated financial statements. The results of operations for interim periods are not necessarily indicative of the results for the full fiscal year. Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles requires the use of estimates and assumptions by management in determining the reported amounts of assets and liabilities, revenue and expenses and disclosures regarding contingent assets and liabilities. Actual results could differ from those estimates. The most significant estimates used in our financial statements affect revenue and cost recognition for construction contracts, the allowance for doubtful accounts, self-insurance accruals, deferred tax assets, warranty accruals, fair value accounting for acquisitions and the quantification of fair value for reporting units in connection with our goodwill impairment testing. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 provides a framework that replaces the existing revenue recognition guidance. The guidance can be applied on a full retrospective or modified retrospective basis whereby the entity records a cumulative effect of initially applying this update at the date of initial application. We currently plan to use the modified retrospective basis on the adoption date. It is effective for annual periods beginning after December 15, 2017, including interim periods within that reporting period. We are currently evaluating the potential impact of this authoritative guidance on our consolidated financial statements. In July 2015, the FASB issued ASU No. 2015-11, “Simplifying the Measurement of Inventory”, which requires that inventory within the scope of the guidance be measured at the lower of cost and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less reasonable predictable costs of completion, disposal and transportation. Inventory measured using last-in, first-out (LIFO) and the retail inventory method (RIM) are not impacted by the new guidance. Entities should apply the new guidance prospectively with earlier application permitted as of the beginning of an interim or annual reporting period. It is effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. We are currently evaluating the potential impact of this authoritative guidance on our consolidated financial statements. In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-02, “Leases (Topic 842)” (“ASU 2016-02”). The standard requires lessees to recognize assets and liabilities for most leases. ASU 2016-02 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018. Early adoption is permitted. ASU 2016-02’s transition provisions are applied using a modified retrospective approach at the beginning of the earliest comparative period presented in the financial statements. Full retrospective application is prohibited. We are currently evaluating the potential impact of this authoritative guidance on our consolidated financial statements. In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (‘‘ASU’’) No. 2016-09, ‘‘Compensation—Stock Compensation (Topic 718)’’ (‘‘ASU 2016-09’’). The standard changes certain aspects of accounting for share-based payments to employees. Specifically, the new guidance requires excess tax benefits and tax deficiencies to be recognized in the income statement instead of additional paid-in capital when the awards vest or are settled. Additionally, cash flows related to excess tax benefits will be presented as an operating activity rather than a financing activity. ASU 2016-09 also allows an employer to repurchase more of an employee’s shares than it previously could for tax withholding purposes without triggering liability accounting and to make a policy election to account for forfeitures as they occur. ASU 2016-09 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2016. Early adoption is permitted, but all of the guidance must be adopted in the same period. We elected to early adopt ASU 2016-09 in the second quarter of 2016 which requires us to reflect any adjustments as of January 1, 2016. The primary impact of adoption was the recognition of $0.1 million of excess tax benefits in our provision for income taxes rather than additional paid-in capital. We have elected to account for forfeitures as they occur to determine the amount of compensation cost to be recognized. The impact of this change in accounting policy was less than $0.1 million and was recorded as a cumulative effect adjustment to retained earnings for the increase to stock compensation expense. Amendments to the accounting for minimum statutory withholding tax requirements had no impact to retained earnings as of January 1, 2016. We elected to apply the presentation requirements for cash flows related to excess tax benefits prospectively which resulted in an increase to net cash provided by operations and a decrease to net cash provided by financing of $0.1 million for the three months ended March 31, 2016. The presentation requirements for cash flows related to employee taxes paid for withheld shares had no impact to our consolidated cash flow statement as such cash flows have historically been presented as a financing activity. Financial Instruments Our financial instruments consist of cash and cash equivalents, accounts receivable, other receivables, accounts payable, life insurance policies, notes to former owners, capital leases and a revolving credit facility. We believe that the carrying values of these instruments on the accompanying balance sheets approximate their fair values. Segment Disclosure Our activities are within the mechanical services industry, which is the single industry segment we serve. Each operating unit represents an operating segment and these segments have been aggregated, as the operating units meet all of the aggregation criteria.

2. Summary of Significant Accounting Policies

Basis of Presentation

These interim statements should be read in conjunction with the historical Consolidated Financial Statements and related notes of Comfort Systems included in the Annual Report on Form 10-K as filed with the Securities and Exchange Commission (“SEC”) for the year ended December 31, 2015 (the “Form 10-K”).

The accompanying unaudited consolidated financial statements were prepared using generally accepted accounting principles for interim financial information and the instructions to Form 10-Q and applicable rules of Regulation S-X of the SEC. Accordingly, these financial statements do not include all the footnotes required by generally accepted accounting principles for complete financial statements and should be read in conjunction with the Form 10-K. We believe all adjustments necessary for a fair presentation of these interim statements have been included and are of a normal and recurring nature. Certain amounts in prior periods may have been reclassified to conform to the current year presentation. The effects of the reclassifications were not material to the unaudited consolidated financial statements. The results of operations for interim periods are not necessarily indicative of the results for the full fiscal year.

Use of Estimates

The preparation of financial statements in conformity with generally accepted accounting principles requires the use of estimates and assumptions by management in determining the reported amounts of assets and liabilities, revenue and expenses and disclosures regarding contingent assets and liabilities. Actual results could differ from those estimates. The most significant estimates used in our financial statements affect revenue and cost recognition for construction contracts, the allowance for doubtful accounts, self-insurance accruals, deferred tax assets, warranty accruals, fair value accounting for acquisitions and the quantification of fair value for reporting units in connection with our goodwill impairment testing.

Recent Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 provides a framework that replaces the existing revenue recognition guidance. The guidance can be applied on a full retrospective or modified retrospective basis whereby the entity records a cumulative effect of initially applying this update at the date of initial application. We currently plan to use the modified retrospective basis on the adoption date. It is effective for annual periods beginning after December 15, 2017, including interim periods within that reporting period. We are currently evaluating the potential impact of this authoritative guidance on our consolidated financial statements.

In July 2015, the FASB issued ASU No. 2015-11, “Simplifying the Measurement of Inventory”, which requires that inventory within the scope of the guidance be measured at the lower of cost and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less reasonable predictable costs of completion, disposal and transportation. Inventory measured using last-in, first-out (LIFO) and the retail inventory method (RIM) are not impacted by the new guidance. Entities should apply the new guidance prospectively with earlier application permitted as of the beginning of an interim or annual reporting period. It is effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. We are currently evaluating the potential impact of this authoritative guidance on our consolidated financial statements.

In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-02, “Leases (Topic 842)” (“ASU 2016-02”). The standard requires lessees to recognize assets and liabilities for most leases. ASU 2016-02 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018. Early adoption is permitted. ASU 2016-02’s transition provisions are applied using a modified retrospective approach at the beginning of the earliest comparative period presented in the financial statements. Full retrospective application is prohibited. We are currently evaluating the potential impact of this authoritative guidance on our consolidated financial statements.

In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (‘‘ASU’’) No. 2016-09, ‘‘Compensation—Stock Compensation (Topic 718)’’ (‘‘ASU 2016-09’’). The standard changes certain aspects of accounting for share-based payments to employees. Specifically, the new guidance requires excess tax benefits and tax deficiencies to be recognized in the income statement instead of additional paid-in capital when the awards vest or are settled. Additionally, cash flows related to excess tax benefits will be presented as an operating activity rather than a financing activity. ASU 2016-09 also allows an employer to repurchase more of an employee’s shares than it previously could for tax withholding purposes without triggering liability accounting and to make a policy election to account for forfeitures as they occur. ASU 2016-09 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2016. Early adoption is permitted, but all of the guidance must be adopted in the same period.

We elected to early adopt ASU 2016-09 in the second quarter of 2016 which requires us to reflect any adjustments as of January 1, 2016. The primary impact of adoption was the recognition of $0.1 million of excess tax benefits in our provision for income taxes rather than additional paid-in capital. We have elected to account for forfeitures as they occur to determine the amount of compensation cost to be recognized. The impact of this change in accounting policy was less than $0.1 million and was recorded as a cumulative effect adjustment to retained earnings for the increase to stock compensation expense. Amendments to the accounting for minimum statutory withholding tax requirements had no impact to retained earnings as of January 1, 2016.

We elected to apply the presentation requirements for cash flows related to excess tax benefits prospectively which resulted in an increase to net cash provided by operations and a decrease to net cash provided by financing of $0.1 million for the three months ended March 31, 2016. The presentation requirements for cash flows related to employee taxes paid for withheld shares had no impact to our consolidated cash flow statement as such cash flows have historically been presented as a financing activity.

Financial Instruments

Our financial instruments consist of cash and cash equivalents, accounts receivable, other receivables, accounts payable, life insurance policies, notes to former owners, capital leases and a revolving credit facility. We believe that the carrying values of these instruments on the accompanying balance sheets approximate their fair values.

Segment Disclosure

Our activities are within the mechanical services industry, which is the single industry segment we serve. Each operating unit represents an operating segment and these segments have been aggregated, as the operating units meet all of the aggregation criteria.