1. Illinois-specific invoice requirements
- Sales tax line: 6.25% state rate. Most services rendered in Illinois are exempt from sales tax — but materials, parts, and tangible goods are not. Services largely exempt; combined rates up to ~11% in Chicago.
- Late-fee cap: Illinois statute 815 ILCS 205/4 (Interest Act) caps interest on unpaid invoices at 1.5% per month. Spell out the rate in writing on every invoice and in your contract — courts won't enforce undisclosed fees.
- Written contract required: Illinois requires a signed agreement for any job over $1,000. Reference the contract number on the invoice.
- Right-to-cancel notice: Customers in Illinois get 72-hour cancellation rights on certain home-services contracts. Disclose this in your terms.
2. HVAC Technician line items + standard terms
Every hvac technician invoice in Illinois should itemize work clearly. Standard hvac technicians use Net 7 terms with a 25% deposit required upfront.
- Diagnostic fee — billed by flat (~$89 default).
- Labor — billed by hour (~$115 default).
- Refrigerant / parts — billed by itemized.
- Service agreement credit — billed by discount.
3. HVAC Technician licensing in Illinois
EPA Section 608 certification required for refrigerant work. State HVAC licenses common.
4. Send and follow up
Send the invoice the same day work completes. Use software that records open events and offers a one-click online payment so you don't need to chase a check by mail. Illinois customers expect digital payment options today — accepting card and ACH typically reduces days-to-paid by 30–50%.
Average invoice
$540
State
IL
Net terms
7 days
Deposit
25%
Illinois metro guides
Metro-specific guides include the combined sales-tax rate and local pricing benchmarks.