For decades, the term "deferred maintenance" in commercial real estate meant something tangible: a deteriorating roof, cracked pavement, outdated HVAC equipment waiting on a capital plan. Appraisers knew how to account for it. They could see it, quantify it, and adjust accordingly. That clarity is disappearing.
A new category of risk is now embedded in aging commercial buildings, one that cannot be seen during a standard site walkthrough. It lives inside mechanical rooms, in the firmware of HVAC systems, and in the absence of integrated data infrastructure. Buildings that lack IoT-enabled mechanicals, MERV 13-compliant filtration systems, or digital operational continuity are no longer simply dated. They are on a path toward functional obsolescence and, in many jurisdictions, toward regulatory non-compliance.
The Regulatory Shift Already Underway
2026 marks an inflection point in building performance regulation. California's updated Title 24 energy standards, effective Jan. 1, 2026, expand requirements for electrification, mechanical system efficiency, and indoor air quality. New York City's 2025 Energy Conservation Code took effect March 30, 2026, applying updated ASHRAE 90.1 standards to new and substantially altered commercial buildings. Nationally, research from JLL indicates that over 40 U.S. cities will have active building performance standards in place by 2026, covering the majority of large commercial buildings nationwide.
The penalties for non-compliance are material. In Washington, D.C., the Building Energy Performance Standards program carries maximum exposure of $10 per square foot of gross floor area, meaning a 100,000-square-foot building faces up to $1,000,000 in fines. Boston's BERDO 2.0 imposes fines of $1,000 per day for buildings over 35,000 square feet that fail to meet emissions limits. New York City's Local Law 97 charges $268 per metric ton of CO2 over the annual allowance. These are not theoretical costs. They are direct charges against net operating income.
What Traditional Appraisal Methods Are Missing
Commercial valuation is fundamentally tied to net operating income and risk. When regulatory penalties compress NOI and when the cost of insurance for mechanically undocumented buildings rises, capitalization rates expand and values fall. This is the logic behind what analysts have begun calling the "brown discount": a measurable reduction in value applied to buildings lagging on energy performance, mechanical transparency, or code alignment.
The problem for appraisers is that the inputs driving this discount are largely invisible. A building's compliance posture, its mechanical service history, the presence or absence of IoT infrastructure, its energy use intensity relative to local benchmarking thresholds: none of these appear on a standard walkthrough. They require data that, in most cases, does not exist in a structured or transferable form.
This creates a significant liability exposure for appraisers. If a valuation fails to account for a building's pending non-compliance costs or its stranded asset risk, the resulting opinion of value may overstate the property's worth in ways that affect lending decisions and, ultimately, the appraiser's professional standing.
The Comparable Sales Problem
Sound appraisal practice requires adjustments based on comparable properties. But comparables are increasingly insufficient when the most material differences between assets are not physical conditions but operational ones. A building with full mechanical documentation, IoT-integrated systems, and a verified compliance history represents a fundamentally different risk profile than a structurally similar building without those attributes, even if they share the same vintage, square footage, and submarket.
The appraisal community needs a framework for capturing and verifying this layer of building data. Concepts like persistent digital infrastructure records, sometimes referred to as a building's "mechanical passport," are emerging as a way to give appraisers verifiable, structured data about a building's operational history that survives ownership transfers. When that history exists, the appraiser has the evidentiary basis to justify value adjustments to lenders and AMC underwriters. When it does not, the appraiser is left estimating a risk they cannot fully see.
Redefining Functional Obsolescence for a New Era
The Uniform Standards of Professional Appraisal Practice define functional obsolescence as a loss in value resulting from deficiencies or superadequacies in the structure itself. Historically, this meant outdated floor plates, insufficient ceiling heights, or inefficient layouts. Today, it must also account for a building's digital and mechanical readiness.
A building without MERV 13 filtration in a post-pandemic leasing market is functionally deficient relative to tenant expectations. A building without IoT-integrated mechanical systems is functionally deficient relative to the operational requirements of institutional tenants and the monitoring mandates of building performance standards. A building without a verifiable energy use history is functionally deficient relative to the data demands of today's underwriters.
These are not upgrades. They are now baseline requirements for competitive positioning, insurability, and access to capital. Appraisers who fail to reflect this in their methodology risk producing valuations that overstate what the market will actually pay for an asset that cannot meet the operational standards of its time.
A Practical Path Forward
Appraisers operating in this environment should consider expanding their due diligence checklists to include energy benchmarking data, mechanical service and upgrade histories, active or pending code compliance status, and the presence of digital infrastructure capable of meeting current monitoring requirements. Where that data is available, it informs more defensible adjustments. Where it is absent, that absence itself is a valuation signal.
The gap between well-capitalized, digitally integrated Class A assets and aging commercial stock is widening. That gap has financial consequences that are now measurable and traceable through regulatory filings, energy disclosures, and insurance underwriting criteria. Appraisers who develop the tools and frameworks to quantify these differences will deliver more accurate, more defensible valuations and will be better positioned as the industry catches up to a new definition of what a functional, financeable building actually looks like.
