But while the headline pointed to relief, the policy that followed is already proving far more complicated than advertised – and, in key respects, still unfinished.

A policy that lowers rates – and widens the net

The proclamation, formally published in the Federal Register on June 4, establishes a tiered tariff system: up to 50 percent for raw metals, 25 percent for many derivative products, and a reduced 15 percent rate for a limited group of industrial and residential equipment, including certain HVAC systems.

That same order also pulled new products into the tariff regime, including steel racks and aluminum lithographic plates, both now subject to 25 percent duties, as detailed in the Federal Register publication.

In effect, the administration did two things at once: it lowered tariffs on some downstream equipment while expanding the scope of goods subject to tariffs overall.

Trade analysts say that structure reflects the administration’s broader balancing act – trying to ease costs for politically sensitive sectors like construction and manufacturing while maintaining pressure on imported metals.

Relief tied to origin – and difficult to qualify for

Even for products that qualify for lower rates, the relief is conditional.

Under the new framework, certain equipment imported from partners with U.S. trade agreements can access the 15 percent rate, while a lower 10 percent tariff is available only if at least 85 percent of the steel or aluminum content is produced in the United States, per the Federal Register and BDO.

That threshold – 85 percent by weight – represents a shift from earlier rules but remains a high bar for global manufacturers with complex supply chains.

Complicating matters further, for goods traded under the U.S.-Mexico-Canada Agreement, tariffs may apply only to the “non‑U.S. content” of the product, though the total duty cannot fall below 15 percent, as explained in JD Supra.

For contractors buying finished equipment, the result is not a simple price adjustment but a matrix of outcomes depending on where a system is built, how it is assembled, and what materials it contains.

The rules exist – but the playbook does not

The administration moved quickly to formalize the policy. The proclamation took effect June 8, and U.S. Customs and Border Protection issued initial implementation guidance the following day, laying out tariff classifications and entry procedures.

But key details that determine how the tariffs are actually applied remain unsettled.

Customs officials acknowledged in that guidance that additional instructions would be released for certain tariff categories and classifications.

Trade lawyers and compliance specialists say the most significant unanswered questions center on how to calculate U.S. content, how to classify borderline products under the tariff schedule, and how to treat equipment assembled from parts sourced across multiple countries.

Even in legal advisories, experts note that Customs is expected to issue further guidance on how to assess U.S. content and apply tariffs in practice, particularly in cases involving mixed-origin materials, as discussed in JD Supra.

That uncertainty is not unusual in trade policy, but it is especially consequential here because the tariff rate depends not just on the product itself but on how it is made.

A shift in how tariffs are calculated

At the same time, the administration has altered the underlying method for calculating tariffs on many imports.

Under earlier rules, tariffs on some products were applied only to the value of the metal content. The current framework applies tariffs to the full customs value of the imported product, a change that significantly increases the effective cost for many manufactured goods, as noted in Construction Dive.

For HVAC equipment – where metal is embedded in fully assembled systems – this shift means tariffs can apply to the entire unit, not just its steel or aluminum components.

That change is expected to ripple through supply chains, affecting manufacturers first but eventually showing up in contractor pricing and project bids.

Contractors face complexity, not clarity

For sheet metal contractors, who typically operate several layers removed from import transactions, the policy is already showing up as uncertainty in quotes rather than immediate savings.

Prices on HVAC equipment remain elevated, in part because suppliers must account for multiple overlapping tariffs, including Section 232 duties on metals and Section 301 tariffs on certain components. And even where rates have technically fallen, manufacturers and distributors are pricing against risk – uncertainty over how a product will ultimately be classified or whether it will meet eligibility requirements.

The new system also introduces more variables into procurement decisions. Two units that appear identical may face different tariff treatments depending on origin, sourcing, or certification of material content.

The policy is law. The interpretation is still coming.

The administration has framed the changes as a targeted effort to support domestic manufacturing while easing pressure on industries that rely on imported equipment. The White House said the adjustments would remain in place through 2027 “to spur near-term investments” and strengthen U.S. industry, as summarized in their fact sheet.

But for companies navigating the system, the immediate reality is less about strategy and more about interpretation.

The framework is in place: the proclamation has been published, the tariff rates are set, and the effective date has passed. What remains unresolved is how to apply those rules to real products moving through real supply chains.

Contractors are unlikely to see that clarity overnight. In the meantime, the headline – tariffs on HVAC have been reduced – is already giving way to a more complicated truth.

The rates may be lower. The system is not simpler.