Window and door cross-border tax: US-made product, CUSMA origin, and USD rebates

Who the importer of record is decides everything downstream

If you buy US-made windows through a Canadian distributor or the manufacturer's Canadian subsidiary, you are a domestic purchaser: the invoice carries HST, the distributor dealt with customs, and your cross-border exposure is limited to whatever tariff cost was passed through in the price. If you buy direct from a US plant and the goods ship to you, you are the importer of record — responsible for classification, origin, duty, the GST at the border, and the records a CBSA verification can ask for up to four years later.

Importers of record must be registered in the CBSA's CARM Client Portal and, since the 2024 changes, post their own financial security for release prior to payment rather than relying on the broker's bond. The import-export program account — the RM extension on your business number — has to exist before the first shipment. A customs broker files the declarations, but the liability is yours. We make sure the accounting side — landed cost by shipment, GST input tax credits, broker disbursements — is set up before the first order rather than reconstructed after.

Classification and CUSMA origin: the paperwork behind duty-free

Windows and doors are classified by frame material, and each heading has its own most-favoured-nation duty rate and its own origin rule under the Canada-United States-Mexico Agreement.

CUSMA preferential treatment is claimed on the declaration, and the claim is only as good as the certification of origin in your file. There is no prescribed form, but it must contain the required data elements, it can be completed by the producer, exporter or importer, and a blanket certification can cover shipments for up to twelve months. Claim the preference without one and a CBSA verification will assess the duty retroactively with interest. Pay duty and later obtain a valid certification, and a refund claim is possible within the statutory window. We keep the certifications with the year-end file, because a missing one is a cost, not a technicality.

Tariffs and surtaxes: what is fixed and what moves

The MFN duty rates and the CUSMA rules are stable. The surtaxes are not. Through 2025 Canada applied countermeasures on lists of US goods that at various points included steel and aluminum products, and the United States applied Section 232 duties on steel and aluminum content that reach some fabricated products. As at the time of writing, whether a given shipment of aluminum-framed or steel-clad product carries an additional surtax depends on the current schedule, the origin of the goods and any remission order in force — and the answer has changed more than once in eighteen months. We check the tariff treatment on each product line before you set a season's pricing, price the exposure into contracts with a materials-adjustment clause where the manufacturer will not hold price, and make sure any surtax paid is captured as landed cost of the specific units so margin per opening stays honest.

The GST side is simpler. As a registrant importing for commercial use you pay the 5% federal part at the border and recover it as an input tax credit, and the Ontario part is neither collected there nor self-assessed. Duty and surtax, by contrast, are part of the cost of the goods and never come back.

USD rebates, co-op funds and the customs value they do not reduce

US manufacturers pay dealer rebates and co-op advertising in US dollars, often by credit on account. In the books they are converted at the rate on the date they became receivable, posted against product cost or the advertising they reimburse, and any difference on settlement is a foreign-exchange gain or loss — the mechanics are in our note on recording USD transactions in Canadian books. One customs point catches dealers by surprise: a rebate received after import does not reduce the value for duty already declared, so a year-end volume rebate does not generate a duty refund even though it lowers your real product cost.

A US manufacturer or programme administrator may ask for a W-8BEN-E before releasing funds. Purchase rebates are not US-source income subject to withholding, but the form is how their accounts-payable system documents that you are a foreign corporation and that no 1099 is required — sign it. Where a US programme charges you a fee for the right to use a brand name, a protected territory or a marketing system rather than for product, that fee can be a royalty for Canadian withholding purposes, with Part XIII tax at the treaty rate withheld and reported on an NR4. Most dealer agreements are product-only; we read the ones that are not.

The occasional US job, kept honest

A Niagara or Windsor dealer will sometimes be asked to install across the river. Under the treaty a Canadian corporation with no permanent establishment in the US owes no US federal income tax on the job, but the position is claimed rather than assumed — a protective Form 1120-F with a treaty disclosure keeps deductions available if the IRS later disagrees — and state contractor registration and state sales tax on installed materials apply regardless of the treaty. For a one-off job those costs usually exceed the margin, and we say so rather than build a US practice around it. For the day-to-day product questions above, our bookkeeping page for dealers shows how landed cost and rebates flow through the ledger, and our cross-border tax services page covers the broader toolkit.

Source: CBSA — CARM: CBSA Assessment and Revenue Management.