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, 2017 (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. 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 Accounting Standards Update (“ASU”) No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” Topic 606 supersedes the revenue recognition requirements in “Revenue Recognition (Topic 605)” and requires entities to recognize revenue when control of the promised goods or services is transferred to customers at an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. We adopted Topic 606 as of January 1, 2018.

In accordance with Topic 606, we applied the modified retrospective method to those contracts which were not completed as of January 1, 2018. Under the modified retrospective method, the cumulative effect of applying the standard is recognized at the date of initial application. Results for reporting periods beginning after January 1, 2018 are presented under Topic 606, while prior period amounts are not adjusted and continue to be reported in accordance with our historic accounting under Topic 605.

In implementing Topic 606, we were required to recalculate the revenue earned on any work in process at the implementation date and to restate the revenue and cost of services as if Topic 606 had been followed from the inception of the contract. In recalculating costs and revenue under Topic 606 guidelines, we identified no material difference in the account balances. Since a material difference was not found, no retrospective analysis of account balance changes was required.

In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842)”. 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 August 2016, the FASB issued ASU No. 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments”. This standard provides guidance on how certain cash receipts and cash payments are presented and classified in the statement of cash flows and is intended to reduce diversity in practice with respect to these items. The standard is applied using a retrospective transition method and is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. We adopted this standard on January 1, 2018 and the adoption did not have any impact on our consolidated financial statements.

Revenue Recognition

Revenue is recognized when control of the promised goods or services is transferred to our customers, in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. Sales-based taxes are excluded from revenue.

We provide comprehensive mechanical contracting services, which principally includes HVAC, plumbing, piping and controls, as well as off‑site construction, electrical, monitoring and fire protection. We install, maintain, repair and replace products and systems throughout the United States. All of our revenue is recognized over time as we deliver goods and services to our customers. Revenue can be earned based on an agreed upon fixed price or based on actual costs incurred marked up at an agreed upon percentage.

For fixed price agreements, we use the percentage of completion method of accounting under which contract revenue recognizable at any time during the life of a contract is determined by multiplying expected total contract revenue by the percentage of contract costs incurred at any time to total estimated contract costs. More specifically, as part of the negotiation and bidding process to obtain installation contracts, we estimate our contract costs, which include all direct materials, labor and subcontract costs and indirect costs related to contract performance, such as indirect labor, supplies, tools, repairs and depreciation costs. These contract costs are included in our results of operations under the caption “Cost of Services.” Then, as we perform under those contracts, we measure costs incurred, compare them to total estimated costs to complete the contract and recognize a corresponding proportion of contract revenue. Labor costs are considered to be incurred as the work is performed. Subcontractor labor is recognized as the work is performed. Non‑labor project costs consist of purchased equipment, prefabricated materials and other materials. Purchased equipment on our projects is substantially produced to job specifications and is a value-added element to our work. The costs are considered to be incurred when title is transferred to us, which typically is upon delivery to the work site. Prefabricated materials, such as ductwork and piping, are generally performed at our shops and recognized as contract costs when fabricated for the unique specifications of the job. Other materials costs are generally recorded when delivered to the work site. This measurement and comparison process requires updates to the estimate of total costs to complete the contract, and these updates may include subjective assessments and judgments.

We account for a contract when: (i) it has approval and commitment from both parties, (ii) the rights of the parties are identified, (iii) payment terms are identified, (iv) the contract has commercial substance, and (v) collectability of consideration is probable. We consider the start of a project to be when the above criteria have been met and we either have written authorization from the customer to proceed or an executed contract.

Selling, marketing and estimation costs incurred in relation to selling contracts are expensed as incurred. On rare occasions, we may incur significant expense related to selling a contract that we only incurred because we sold that contract. If this occurs, we capitalize that cost and amortize it on a straight-line basis over the expected life of the job. We do not currently have any capitalized selling, marketing, or estimation costs on our Balance Sheet and did not incur any impairment loss in the current year.

We generally do not incur significant incremental costs related to obtaining or fulfilling a contract prior to the start of a project. On rare occasions, when significant pre‑contract costs are incurred, they are capitalized and amortized on a percentage of completion basis over the life of the contract. We do not currently have any capitalized obtaining or fulfillment costs on our Balance Sheet and did not incur any impairment loss on such costs in the current year.

Project contracts typically provide for a schedule of billings or invoices to the customer based on our job to date percentage of completion of specific tasks inherent in the fulfillment of our performance obligation(s). The schedules for such billings usually do not precisely match the schedule on which costs are incurred. As a result, contract revenue recognized in the statement of operations can and usually does differ from amounts that can be billed or invoiced to the customer at any point during the contract. Amounts by which cumulative contract revenue recognized on a contract as of a given date exceed cumulative billings and unbilled receivables to the customer under the contract are reflected as a current asset in our balance sheet under the caption “Costs and estimated earnings in excess of billings” and “Unbilled accounts receivable.” Amounts by which cumulative billings to the customer under a contract as of a given date exceed cumulative contract revenue recognized on the contract are reflected as a current liability in our balance sheet under the caption “Billings in excess of costs and estimated earnings.”

We typically invoice our customers with payment terms of net due in 30 days. It is common in the construction industry for a contract to specify specific more lenient payment terms allowing the customer 45 to 60 days to make their payment. It is also common for the contract in the construction industry to specify that a general contractor is not required to submit payments to a subcontractor until it has received those funds from the owner or funding source. In most instances we receive payment of our invoices between 30 to 90 days of the date of the invoice.

A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account in ASC Topic 606. A contract’s transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied.

To determine the proper revenue recognition method for contracts, we evaluate whether two or more contracts should be combined and accounted for as one performance obligation and whether the combined or single contract should be accounted for as more than one performance obligation. This evaluation requires significant judgment and the decision to combine a group of contracts or separate the combined or single contract into multiple performance obligations could change the amount of revenue and profit recorded in a given period. For most of our contracts, the customer contracts with us to provide a significant service of integrating a complex set of tasks and components into a single project or capability (even if that single project results in the delivery of multiple units). Hence, the entire contract is accounted for as one performance obligation. Less commonly, however, we may promise to provide distinct goods or services within a contract in which case we separate the contract into more than one performance obligation. If a contract is separated into more than one performance obligation, we allocate the total transaction price to each performance obligation in an amount based on the estimated relative standalone selling prices of the promised goods or services underlying each performance obligation. We infrequently sell standard products with observable standalone sales. In cases where we do, the observable standalone sales are used to determine the standalone selling price. More frequently, we sell a customized customer specific solution, and in these cases we typically use the expected cost plus a margin approach to estimate the standalone selling price of each performance obligation.

We recognize revenue over time for all of our services as we perform them, because (i) control continuously transfers to that customer as work progresses, and (ii) we have the right to bill the customer as costs are incurred. The customer typically controls the work in process as evidenced either by contractual termination clauses or by our rights to payment for work performed to date plus a reasonable profit to deliver products or services that do not have an alternative use to the Company.

Because of control transferring over time, revenue is recognized based on the extent of progress towards completion of the performance obligation. The selection of the method to measure progress towards completion requires judgment and is based on the nature of the products or services to be provided. We generally use the cost to cost measure of progress for our contracts as it best depicts the transfer of assets to the customer that occurs as we incur costs on our contracts. Under the cost to cost measure of progress, the extent of progress towards completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation. Revenue, including estimated fees or profits, is recorded proportionally as costs are incurred. Costs to fulfill include labor, materials and subcontractors’ costs, other direct costs and an allocation of indirect costs.

For a small portion of our business where our services are delivered in the form of service maintenance agreements for existing systems to be repaired and maintained, as opposed to constructed, our performance obligation is to maintain the customer’s mechanical system for a specific period of time. Similar to jobs, we recognize revenue over time; however, for service maintenance agreements where the full cost to provide services may not be known, we generally use an output method to recognize revenue, which is based on the amount of time we have provided our services out of the total time we have been contracted to perform those services.

Due to the nature of the work required to be performed on many of our performance obligations, the estimation of total revenue and cost at completion (the process described below in more detail) is complex, subject to many variables and requires significant judgment. The consideration to which we are entitled on our long-term contracts may include both fixed and variable amounts. Variable amounts can either increase or decrease the transaction price. A common example of variable amounts that can either increase or decrease contract value are pending change orders that represent contract modifications for which a change in scope has been authorized or acknowledged by our customer, but the final adjustment to contract price is yet to be negotiated. Other examples of positive variable revenue include amounts awarded upon achievement of certain performance metrics, program milestones or cost of completion date targets and can be based upon customer discretion. Variable amounts can result in a deduction from contract revenue if we fail to meet stated performance requirements, such as being in compliance with the construction schedule.

Contracts are often modified to account for changes in contract specifications and requirements. We consider contract modifications to exist when the modification either creates new or changes the existing enforceable rights and obligations. Most of our contract modifications are for goods or services that are not distinct from the existing performance obligation(s). The effect of a contract modification on the transaction price, and our measure of progress for the performance obligation to which it relates, is recognized as an adjustment to revenue (either as an increase or decrease) on a cumulative catchup basis.

We have a Company-wide policy requiring periodic review of the Estimate at Completion in which management reviews the progress and execution of our performance obligations and estimated remaining obligations. As part of this process, management reviews information including, but not limited to, any outstanding key contract matters, progress towards completion and the related program schedule, identified risks and opportunities and the related changes in estimates of revenue and costs. The risks and opportunities include management's judgment about the ability and cost to achieve the schedule (e.g., the number and type of milestone events), technical requirements (e.g., a newly developed product versus a mature product) and other contract requirements. Management must make assumptions and estimates regarding labor productivity and availability, the complexity of the work to be performed, the availability of materials, the length of time to complete the performance obligation (e.g. to estimate increases in wages and prices for materials and related support cost allocations), execution by our subcontractors, the availability and timing of funding from our customer, and overhead cost rates, among other variables.

Based on this analysis, any adjustments to revenue, cost of services, and the related impact to operating income are recognized as necessary in the quarter they become known. These adjustments may result from positive program performance if we determine we will be successful in mitigating risks surrounding the technical, schedule and cost aspects of those performance obligations or realizing related opportunities and may result in an increase in operating income during the performance of individual performance obligations. Likewise, if we determine we will not be successful in mitigating these risks or realizing related opportunities these adjustments may result in a decrease in operating income. Changes in estimates of revenue, cost of services and the related impact to operating income are recognized quarterly on a cumulative catchup basis, which recognizes in the current period the cumulative effect of the changes on current and prior periods based on a performance obligation's percentage of completion. A significant change in one or more of these estimates could affect the profitability of one or more of our performance obligations. For projects where estimates of total costs to be incurred on a performance obligation exceed total estimates of revenue to be earned, a provision for the entire loss on the performance obligation is recognized in the period the loss is determined.

The Company typically does not incur any returns, refunds, or similar obligations after the completion of the performance obligation since any deficiencies are corrected during the course of the work or are included as a modification to revenue. The Company does offer an industry standard warranty on our work, which is most commonly for a one-year period. The vendors providing the equipment and materials are responsible for any failures in their product unless installed incorrectly. We include an estimated amount to cover estimated warranty expense in our Cost of Services and record a liability on our Balance Sheet to cover our current estimated outstanding warranty obligations.

Prior to implementing ASC 606 on January 1, 2018, our methods for recognizing revenue were very similar to our current method under ASC 606. We used the actual cost as a percent of total expected cost at completion to estimate our percentage complete on fixed price jobs, a mark-up of costs for jobs where revenue was based on time and materials incurred and elapsed time for those service maintenance contracts where the full cost to provide the services cannot be reasonably estimated. Furthermore, our process for allocating transaction price to performance obligations is also substantially similar to prior years where, in most cases, a contract is one performance obligation. In those cases where a contract is determined to have more than one performance obligation, the contract price is allocated to each performance obligation based on its standalone sales price.

In the first six months of 2018, net revenue recognized from our performance obligations satisfied in previous periods was not material.

Disaggregation of Revenue

We disaggregate our revenue from contracts with customers by activity, customer type and contract type, as we believe it best depicts how the nature, amount, timing and uncertainty of our revenue and cash flows are affected by economic factors. Our consolidated 2018 revenue was derived from the following service activities, all of which are in the mechanical services industry, the single industry segment we serve. See details in the following tables (dollars in thousands):


	Three Months Ended June 30,								Six Months Ended June 30,
Revenue by Service Provided	2018				2017				2018				2017
HVAC and Plumbing	$	484,011	90	%	$	422,676	91	%	$	908,028	91	%	$	761,399	90	%
Building Automation Control Systems		26,261	5	%		27,925	6	%		46,306	5	%		50,760	6	%
Other		24,771	5	%		14,810	3	%		45,650	4	%		33,840	4	%
Total	$	535,043	100	%	$	465,411	100	%	$	999,984	100	%	$	845,999	100	%

	Three Months Ended June 30,								Six Months Ended June 30,
Revenue by Type of Customer	2018				2017				2018				2017
Industrial	$	114,077	21	%	$	97,756	21	%	$	214,177	21	%	$	185,370	22	%
Education		109,447	20	%		89,274	19	%		197,650	20	%		150,862	18	%
Office Buildings		79,309	15	%		76,470	16	%		148,429	15	%		128,904	15	%
Healthcare		71,930	13	%		59,322	13	%		135,113	14	%		111,089	13	%
Government		37,285	7	%		35,323	8	%		73,432	7	%		71,559	8	%
Retail, Restaurants and Entertainment		56,204	11	%		54,669	12	%		108,991	11	%		99,894	12	%
Multi-Family and Residential		36,040	7	%		30,260	7	%		69,092	7	%		57,130	7	%
Other		30,751	6	%		22,337	4	%		53,100	5	%		41,191	5	%
Total	$	535,043	100	%	$	465,411	100	%	$	999,984	100	%	$	845,999	100	%

	Three Months Ended June 30,								Six Months Ended June 30,
Revenue by Activity Type	2018				2017				2018				2017
New Construction	$	183,998	34	%	$	178,392	38	%	$	367,435	37	%	$	326,903	39	%
Existing Building Construction		207,775	39	%		146,980	32	%		362,972	36	%		265,246	31	%
Service Projects		51,586	10	%		46,428	10	%		91,761	9	%		89,037	11	%
Service Calls, Maintenance and Monitoring		91,684	17	%		93,611	20	%		177,816	18	%		164,813	19	%
Total	$	535,043	100	%	$	465,411	100	%	$	999,984	100	%	$	845,999	100	%

Accounts Receivables

Accounts Receivable, include amounts billed and billable from work completed in which we have billed or have an unconditional right to bill our customers. The amounts due are stated at their net estimated realizable value. We maintain an allowance for doubtful accounts to provide for the estimated amount of receivables that will not be collected. The allowance is based upon an assessment of customer creditworthiness, historical payment experience, the age of outstanding receivables and collateral to the extent applicable.

Contract Assets and Liabilities

Contract assets include unbilled amounts typically resulting from sales under long term contracts when the cost to cost method of revenue recognition is used and revenue recognized exceeds the amount billed to the customer and right to payment is conditional, subject to completing a milestone, such as a phase of the project. Contract assets are generally classified as current.

Contract liabilities consist of advance payments and billings in excess of revenue recognized. Our contract assets and liabilities are reported in a net position on a contract by contract basis at the end of each reporting period. We classify advance payments and billings in excess of revenue recognized as current. It is very unusual for us to have advanced payments with a term of greater than one year; therefore, our contract assets are usually all current. If we have advanced payments with a term greater than one year, the noncurrent portion of advanced payments would be included in other long-term liabilities in our consolidated balance sheets.

The following table presents the changes in contract assets and contract liabilities (in thousands):


	Six Months Ended
	June 30, 2018
	Contract		Contract
	Assets		Liabilities
Balance at beginning of period	$	30,116	$	106,005
Change due to acquisitions		658		3,126
Change due to conditional versus unconditional		5,454		—
Reclassified to unbilled accounts receivable		(28,980)		—
Change in timing for performance obligation to be satisfied		—		24,831
Balance at June 30, 2018	$	7,248	$	133,962

In the first six months of 2018 and 2017, we recognized revenue of $94.2 million and $83.5 million related to our contract liabilities at January 1, 2018 and January 1, 2017, respectively.

We did not have any impairment losses recognized on our receivables or contract assets in the first six months of 2018 and 2017.

Remaining Performance Obligations

Remaining construction performance obligations represent the remaining transaction price of firm orders for which work has not been performed and excludes unexercised contract options. As of June 30, 2018, the aggregate amount of the transaction price allocated to remaining performance obligations was $1.23 billion. The Company expects to recognize revenue on approximately 85% of the remaining performance obligations over the next 12 months, with the remaining recognized thereafter. Our service maintenance agreements are generally one-year renewable agreements. We have adopted the practical expedient that allows us to not include service maintenance contracts less than one year, therefore we do not report unfulfilled performance obligations for service maintenance agreements.

Income Taxes

We conduct business throughout the United States in virtually all fifty states. Our effective tax rate changes based upon our relative profitability, or lack thereof, in states with varying tax rates and rules. In addition, discrete items, such as tax law changes, judgments and legal structures can impact our effective tax rate. These items can also include the tax treatment for impairment of goodwill and other intangible assets, changes in fair value of acquisition-related assets and liabilities, tax reserves for uncertain tax positions, accounting for losses associated with underperforming operations and noncontrolling interests.

Our provision for income taxes was reduced by $2.8 million in the first quarter of 2018 due to a decrease in unrecognized tax benefits from the filing of a federal income tax automatic accounting method change application.

While we believe we were able to make reasonable estimates of the impact of the Tax Cuts and Jobs Act in our financial statements, the amounts recorded are provisional and the final impact may differ from these estimates due to, among other things, changes in our interpretations and assumptions and additional guidance that may be issued by regulatory authorities.

Other Income

In April 2018, we entered into settlement agreements with British Petroleum (“BP”) related to two claims from one of our subsidiaries regarding the April 2010 BP Deepwater Horizon oil spill. We recorded a gain of $4.0 million in the second quarter of 2018 as a result of these settlements. We do not have any remaining subsidiaries with outstanding claims against BP related to this matter

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.