Is Comfort Systems USA, Inc. overvalued or undervalued?

As of 24 October 2025, the valuation grade for Comfort Systems USA, Inc. moved from attractive to fair, indicating a shift in its perceived value. The company appears to be overvalued based on its current metrics, with a P/E ratio of 31, a Price to Book Value of 11.59, and an EV to EBITDA of 21.24. In comparison to peers, Comfort Systems is considered expensive, with EMCOR Group, Inc. showing a more favorable P/E of 29.12 and EV to EBITDA of 19.49, while AECOM is also deemed very expensive with a P/E of 22.09.
Despite its strong performance, with a year-to-date return of 131.49% compared to the S&P 500's 15.47%, the high valuation ratios suggest that the stock may not be a bargain at its current price. The company's PEG ratio of 0.45 indicates potential growth, but the overall valuation metrics and peer comparisons suggest caution for investors considering entry at this level.