GST/QST invoicing for HVAC-R and HVAC contractors in Quebec

In Quebec, invoicing as a refrigeration tech, AC tech, or HVAC contractor involves two taxes: the GST (5%) administered by the Canada Revenue Agency and the QST (9.975%) administered by Revenu Québec. Here's what you need to know.

Do you need to register for GST and QST?

Registration is required once your gross revenue over the last 4 consecutive quarters exceeds $30,000. Below that threshold, you're considered a "small supplier" and registration is voluntary.

Voluntary registration: pros

• You can recover GST/QST paid on business purchases (tools, refrigerant, vehicle, software)
• More professional image with business customers
• Mandatory once you hit $30,000 anyway, may as well start early

Voluntary registration: cons

• You must file quarterly or annual returns
• Your invoices become more expensive for retail customers (who can't recover the taxes)

Required information on a GST/QST invoice

A compliant invoice must include:

• Your name or business name and contact information
• Your GST and QST numbers (format: 123456789 RT0001 for GST, 1234567890 TQ0001 for QST)
• Customer name and address (mandatory if > $150)
• Invoice date
• Sequential invoice number
• Clear description of goods or services
• Line items: subtotal, GST (5%), QST (9.975%), total

Calculating QST correctly

Heads up: QST is calculated on the pre-GST subtotal, not on the already-taxed subtotal. This is a common error.

Example for a $500 service call:

• Subtotal: $500.00
• GST (5%): $25.00
• QST (9.975%): $49.88 (on $500, not on $525)
• Total: $574.88

Filing frequency

• Under $1.5M in sales: annual or quarterly filing (your choice)
• $1.5M to $6M: quarterly required
• Over $6M: monthly required

QuickBooks and accounting export

In Quebec, the vast majority of HVAC contractors use QuickBooks for accounting. The ideal setup is field service software that generates a QuickBooks-compatible CSV export so you don't have to re-enter everything.

Automating GST/QST invoicing

Quality trade-specific software for Quebec should:

• Automatically calculate GST and QST on every invoice
• Include your GST/QST numbers in the header
• Generate compliant PDFs with all required information
• Export a QuickBooks-compatible CSV for accounting
• Manage automatic sequential invoice numbering

That's exactly what FrigoTechPro does — built for Quebec, not translated from American software. Try it free for 14 days.